Patient Expectations and Satisfaction in Pediatric Orthopedics.

PURPOSE OF REVIEW: The purpose of the current review is to analyze the current literature regarding the tools available to evaluate patient expectations and satisfaction. There have been an increasing number of tools that have been developed and validated for various orthopedic procedures. Despite the growing number of tools, there are a limited number of tools available for pediatric patients. RECENT FINDINGS: Several tools have been developed in orthopedics to evaluate patient expectations. However, there are no tools that have been validated in the pediatric population. In addition, pediatric patient expectations should be collected in conjunction with parent/caregiver expectations. Although not specifically validated for pediatric patients, there are several tools available that may pertain to pediatric patients including the HSS ACL Expectations Survey, HSS Shoulder Expectations Survey, HSS Knee Surgery Expectations Survey, HSS Foot and Ankle Surgery Expectation Survey, Sunnybrook Surgery Expectations Survey, Musculoskeletal Outcomes Data Evaluation and Management System (MODEMS) Instruments, Quick DASH, and DASH. In terms of patient satisfaction, there are even fewer tools available. Several tools have been developed to evaluate patient satisfaction and five additional tools within orthopedics. Of these tools, there are two that have been validated for pediatric patients: The Swedish Parents Satisfaction Questionnaire and the Scoliosis Research Society-22. There are a growing number of tools to evaluate patient's expectations and satisfaction in the orthopedic literature. Given most of these tools pertain to adult patients, there is a need for further development of tools specifically validated for pediatric patients and their parents/caregivers. Through the measurement of expectations and satisfaction, medical professionals can hope to improve satisfaction and outcomes.

Rates and Factors Associated With Hardware Removal in Physeal Ankle Fractures: Analysis of the Pediatric Health Information System.

Background: Ankle fractures are among the most common physeal fractures in children. When surgical management is warranted, subsequent hardware removal remains controversial. This study was designed to determine rates of hardware removal in patients with physeal ankle fractures and identify risk factors for removal. Procedure data was utilized to compare rates of subsequent ankle procedures in patients with hardware removed and hardware retained. Methods: We conducted a retrospective cohort study utilizing data from the Pediatric Health Information System (PHIS) for the years 2015 through 2021. We longitudinally followed patients treated for distal tibia physeal fractures to determine the rates of hardware removal and subsequent ankle procedures. Patients with open fractures or polytrauma were excluded. We used univariate, multivariate, and descriptive statistics to characterize the rates of hardware removal, identify factors associated with removal, and assess the rates of subsequent procedures. Results: This study included 1008 patients who underwent surgical management of a physeal ankle fracture. The mean age at index surgery was 12.6 years with an SD of 2.2 years, and 60% of patients identified as male. Two hundred forty-two patients (24%) had their hardware removed at an average time of 276 days (range, 21-1435 days) following index surgery. Patients with Salter Harris III (SH-III) or Salter Harris IV (SH-IV) fractures had hardware removed more often than patients with Salter-Harris II (SH-II) fractures (28.9% vs 11.7%, P < .01). Four-year rates of subsequent ankle procedures are similar between patients with hardware removed and hardware retained. Conclusion: The rate of hardware removal in children with physeal ankle fractures is higher than previously reported. Patients of younger age, higher income, and with fractures involving the epiphysis (SH-III and SH-IV) are more likely to undergo hardware removal. Level of Evidence: Level III, retrospective study.

Diagnosis and Management of Spondylolysis and Spondylolisthesis in Children.

¼: Spondylolysis is defined as a defect of the pars interarticularis, and spondylolisthesis is defined as a slippage of a vertebra relative to the immediately caudal vertebra. ¼: Most cases of spondylolysis and low-grade spondylolisthesis can be treated nonoperatively. Depending on a patient's age, nonoperative treatment may include a thoracolumbosacral orthosis (TLSO), physical therapy, and activity modification. Bracing and physical therapy have been found to be more effective than activity modification alone. ¼: Patients with dysplastic spondylolisthesis are at higher risk for progression and should be monitored with serial radiographs every 6 to 9 months. ¼: Operative management is recommended for symptomatic patients with failure of at least 6 months of nonoperative management or patients with high-grade spondylolisthesis. ¼: Surgical techniques include pars defect repair, reduction, and fusion, which may include posterior-only, anterior-only, or circumferential fusion.

Rate of utilization of physical therapy after common pediatric elbow fractures.

Supracondylar, medial epicondyle and lateral condyle fractures are the three most common elbow fractures in pediatric patients. There is a paucity of literature discussing the utilization of physical therapy following these injuries. The purpose of the current study was to determine the rate of utilization of physical therapy after these injuries as well as determine factors that may affect the need for physical therapy after common elbow fractures in pediatric patients. We retrospectively chart reviewed all pediatric elbow fractures that were managed at a major pediatric health system from 2013 to 2020. This study included patients under the age of 18 years and utilized International Classification of Diseases (ICD)-9, ICD-10 and Current Procedural Terminology codes to identify patients. Descriptive statistics, chi-square test and multivariate analyses were performed to compare differences between groups. This study included 2037 patients. Overall, 90 patients (4.4%) received a physical therapy referral at an average time of 90.1 (± 54.6) days between discharge and referral. The rate of physical therapy was 2.7% after nonoperative and 6.3% after operative treatment (P < 0.01). Overall, patients that sustained medial epicondyle fractures were prescribed physical therapy at a higher rate (19.8%) than supracondylar (1.4%) or lateral condyle fractures (5.0%) (P < 0.01). For each fracture type, physical therapy utilization was higher among those treated operatively versus those treated nonoperatively (P < 0.01). Physical therapy is more commonly prescribed for patients with medial epicondyle fractures and patients that received operative management. Additional research is needed to determine clinical indications and efficacy of physical therapy after common elbow fractures in pediatric patients.

Diagnosis and Management of Unstable Slipped Capital Femoral Epiphysis: A Critical Analysis Review.

¼: An unstable slipped capital femoral epiphysis (SCFE) is characterized by the inability to walk and is associated with a high risk of osteonecrosis. ¼: An unstable SCFE is less common than a stable SCFE; however, the demographics are similar in both groups of patients with SCFE. ¼: The diagnosis of an unstable SCFE is characterized by a history of antecedent pain and the inability to walk on examination, and it is confirmed by radiographic assessment. ¼: Management of an unstable SCFE includes closed reduction, open reduction, and capital realignment, which have all been noted to have lower rates of osteonecrosis than reported in historic reports. ¼: All management approaches have certain advantages and disadvantages, and comparative studies are needed to guide clinical decision-making.

Opioid Prescriptions After Pediatric Orthopedic Surgery: Analyzing Rates of Unfilled Prescriptions.

BACKGROUND: The prevalence of nonmedical use of prescription opioids among American teenagers is staggering. Reducing the quantity of postoperative opioid prescriptions can help address this epidemic by decreasing the availability of opioids. As the fourth most common opioid prescribers, orthopaedic surgeons are primed to lead efforts to reverse this crisis. The purpose of this study was to determine patient factors associated with filling opioid prescriptions after pediatric orthopaedic surgery and to recommend potential methods to limit excess opioid prescriptions. METHODS: This retrospective cohort study included 1413 patients who were prescribed opioids upon discharge after an orthopaedic surgical procedure at a single urban children's hospital from 2017 to 2018. The state's Prescription Drug Monitoring Program was used to determine which patients filled their opioid prescriptions. Comparisons of demographic, clinical, and surgical factors were made between patients that filled their opioid prescription upon discharge and those that did not. Statistical analysis included λ2, Mann-Whitney U, and binary logistic regression for significant factors from bivariate analysis. RESULTS: Nine percent (n=127) of patients did not fill their opioid prescriptions after discharge. Those who filled and did not fill prescriptions were similar in terms of sex, ethnicity, race, insurance type, and age at surgery (P>0.05). Patients who did not fill their opioid prescriptions received significantly fewer opioids during their postoperative hospital course (5.3 vs. 7.7 mg oxycodone, P=0.01). Not receiving oral oxycodone during postoperative hospitalization (odds ratio=2.16, 95% confidence interval: 1.49-3.14) and undergoing upper extremity surgery (odds ratio=2.00, 95% confidence interval: 1.37-2.91) were independently associated with not filling opioid prescriptions after surgery in the multivariate analysis. CONCLUSIONS: This study identified a subset of pediatric orthopaedic surgery patients who were prescribed opioids upon discharge but did not fill those prescriptions. Factors that increased the likelihood that patients did not fill their prescriptions upon discharge included fewer postoperative hospital course opioids, no oral oxycodone, and surgery on the upper extremity. Future studies must be performed to help decrease the number of opioids prescribed unnecessarily. LEVEL OF EVIDENCE: Level III-prognostic cohort study.

Soft Landing technique as a possible prevention strategy for proximal junctional failure following adult spinal deformity surgery.

BACKGROUND: This cross sectional study describes a "Soft Landing" strategy utilizing hooks for minimizing proximal junctional kyphosis (PJK) and proximal junctional failure (PJF). The technique creates a gradual transition from a rigid segmental construct to unilateral hooks at the upper instrumented level and preservation of the soft tissue attachments on the contralateral side of the hooks. Authors devise a novel classification system for better grading of PJK severity. METHODS: Thirty-nine consecutive adult spinal deformity (ASD) patients at a single institution received the "Soft Landing" technique. The proximal junctional angle was measured preoperatively and at last follow-up using standing 36-inch spinal radiographs. Changes in proximal junctional angle and rates of PJK and PJF were measured and used to create a novel classification system for evaluating and categorizing ASD patients postoperatively. RESULTS: The mean age of the cohort was 61.4 years, and 90% of patients were women. Average follow up was 2.2 years. The mean change in proximal junctional angle was 8° (SD 7.4°) with the majority of patients (53%) experiencing less than 10° and only 1 patients with proximal junctional angle over 20°. Four patients (10%) needed additional surgery for proximal extension of the uppermost instrumented vertebra (UIV) secondary to PJF. CONCLUSIONS: Soft Landing technique is a possibly effective treatment strategy to prevent PJK and PJF following ASD that requires further evaluation. The described classification system provides management framework for better grading of PJK. The "Soft Landing" technique warrants further comparison to other techniques currently used to prevent both PJK and failure.

Refilling Opioid Prescriptions After Pediatric Orthopaedic Surgery: An Analysis of Incidence and Risk Factors.

BACKGROUND: Understanding which pediatric patients seek opioid refills is crucial as prescription opioid use in childhood is associated with an increased risk of future opioid misuse. Orthopaedic surgeons are optimally positioned to lead the charge in addressing the opioid epidemic. The aim of this study was to describe the incidence of and risk factors associated with requiring opioid refills after pediatric orthopaedic surgery in children. METHODS: This retrospective case-control study included 1413 patients aged 0 to 18 years that underwent orthopaedic surgery at a single tertiary care children's hospital and were prescribed opioids at discharge. Using the state Prescription Drug Monitoring Program (PDMP) database, we determined which patients filled additional opioid prescriptions within 6 months following an orthopaedic procedure. Comparisons were made between patients that sought additional opioids and those that did not use bivariate analysis and binomial logistic regression. RESULTS: In total, 31 (2.2%) patients sought additional opioid prescriptions a median 41 days postoperatively (range, 2 to 184). Nearly half of these patients obtained refills from providers outside of our institution, suggesting that previous reports using hospital records may underestimate its prevalence. Factors associated with requiring opioid refills included receiving hydromorphone [odds ratio (OR)=3.04, P=0.04] or methadone (OR=38.14, P<0.01) while inpatient, surgery on the axial skeleton (OR=5.42, P=0.01) or lower extremity (OR=2.49, P=0.04), and nonfracture surgery (OR=3.27, P=0.01). Patients who obtained additional opioids received significantly more opioids during their inpatient recovery (32.9 vs. 11.1 morphine equivalents, P<0.01). CONCLUSIONS: Approximately 2% of children and families obtain additional opioids within 6 months of orthopaedic surgery. The volume of opioids during inpatient hospitalization may predict the need for opioid prescription refills after discharge. Clinicians should maximize efforts to achieve pain control with multimodal analgesia and opioid alternatives, and use caution when administering high-dose opioids during postoperative hospitalization. LEVEL OF EVIDENCE: Level III-prognostic.

Outcomes After Surgical Fixation of Posterior Sternoclavicular Physeal Fractures and Dislocations in Children.

BACKGROUND: Acute sternoclavicular fractures and dislocations (SCFDs) are a rare but important injury in pediatric patients. SCFDs are either true dislocations, or more commonly, physeal fractures in children. The reduction is advised given the proximity to surrounding vascular structures, and some authors advocate for routine fixation given rates of redisplacement after closed reduction. The purpose of the current study was to provide validated long-term functional outcome data following open reduction and surgical fixation of pediatric SCFDs, as well as provide injury and demographic information. METHODS: This is a retrospective observational study with a subset of patients reporting functional outcomes. Patients under the age of 18 that had surgically managed acute posterior SCFD from 1990 to 2018 were included. A retrospective chart review was performed to obtain demographic, clinical, and surgical details. Patients with a minimum of 6-month follow-up were contacted to assess outcomes. Functional outcomes of interest included QuickDash, Visual Analog Scale pain rating, Single Assessment Numeric Evaluation of shoulder function, and PROMIS Upper Extremity questionnaire. Statistical analysis included descriptive statistics. RESULTS: A total of 37 patients that sustained an acute posterior SCFD during the study period were included. The average age at the time of injury was 15.2±2.1 years and 89% were male. Patient-reported outcomes were obtained for 14 patients with a mean follow-up of 4.5 years. The mean QuickDash score was 5.1/100 with 0 being normal, and the mean Visual Analog Scale pain rating was 0.7/10. The mean Single Assessment Numeric Evaluation score was 96% with 100% being completely normal. The mean PROMIS score was 55 with 50 being the mean of the relevant reference population. Approximately 29% (4/14 patients) stated that their injury negatively affected their ability to participate in sports. CONCLUSIONS: There is a paucity of literature on functional outcomes after surgical management of pediatric acute posterior SCFD. Functional outcomes after surgery were satisfactory in this cohort with most patients being able to perform major activities of daily living. Additional future studies with larger cohorts and comparative groups are needed to better understand outcomes in this population. LEVEL OF EVIDENCE: Level IV.

Change in rates of primary atlantoaxial spinal fusion surgeries in the United States (1993-2015).

OBJECTIVE: The objective of this study was to investigate revision burden and associated demographic and economic data for atlantoaxial (AA) fusion procedures in the US. METHODS: Patient data from the National Inpatient Sample (NIS) database for primary AA fusion were obtained from 1993 to 2015, and for revision AA fusion from 2006 to 2014 using ICD-9 procedure codes. Data from 2006 to 2014 were used in comparisons between primary and revision surgeries. National procedure rates, hospital costs/charges, length of stay (LOS), routine discharge, and mortality rates were investigated. RESULTS: Between 1993 and 2014, 52,011 patients underwent primary AA fusion. Over this period, there was a 111% increase in annual number of primary surgeries performed. An estimated 1372 patients underwent revision AA fusion between 2006 and 2014, and over this time period there was a 6% decrease in the number of revisions performed annually. The 65-84 year-old age group increased as a proportion of primary AA fusions in the US from 35.9% of all AA fusions in 1997 to 44.2% in 2015, an increase of 23%. The mean hospital cost for primary AA surgery increased 32% between 2006 and 2015, while the mean cost for revision AA surgery increased by 35% between 2006 and 2014. Between 2006 and 2014, the mean hospital charge for primary AA surgery increased by 67%; the mean charge for revision surgery over that same period increased by 57%. Between 2006 and 2014, the mean age for primary AA fusions was 60 years, while the mean age for revision AA fusions was 52 years. The mean LOS for both procedures decreased over the study period, with primary AA fusion decreasing by 31% and revision AA fusion decreasing by 24%. Revision burden decreased by 21% between 2006 and 2014 (mean 4.9%, range 3.2%-6.4%). The inpatient mortality rate for primary AA surgery decreased from 5.3% in 1993 to 2.2% in 2014. CONCLUSIONS: The number of primary AA fusions between 2006 and 2014 increased 22%, while the number of revision procedures has decreased 6% over the same period. The revision burden decreased by 21%. The inpatient mortality rate decreased 62% (1993-2014) to 2.2%. The increased primary fusion rate, decreased revision burden, and decreased inpatient mortality determined in this study may suggest an improvement in the safety and success of primary AA fusion.

Open Reduction and Suture Fixation of Acute Sternoclavicular Fracture-Dislocations in Children.

BACKGROUND: Acute sternoclavicular fracture-dislocation is associated with high-energy trauma and is being increasingly recognized in children1. These injuries are associated with compression of mediastinal structures and can be life-threatening1. The management of acute sternoclavicular fracture-dislocation includes closed reduction or open surgical stabilization; however, limited success is reported with closed reduction2,3. To our knowledge, there are no detailed descriptions of open reduction and suture fixation of acute sternoclavicular fracture-dislocation in children. DESCRIPTION: Following diagnosis of acute sternoclavicular fracture-dislocation, the timing of surgical treatment is determined according to several patient and surgical factors. Among patients with hemodynamic instability, respiratory compromise, or evidence of asymmetric perfusion, surgical treatment is needed on an emergency basis. In the absence of these factors, surgical treatment can be performed on an urgent basis. It is important to communicate with vascular or thoracic surgeons prior to proceeding to the operating room because of the rare case in which advanced surgical access or vascular repair is required. In the operating room, general anesthesia and large-bore intravenous access are required. Patients are positioned supine on a radiolucent table, and a small bump is placed between the scapulae to elevate the medial aspect of the clavicle. The contralateral sternoclavicular joint and medial aspect of the clavicle should be prepared into the sterile field, as well as both sides of the groin in case vascular access is needed. A 6 to 8-cm incision is centered on the medial aspect of the clavicle, extending to the manubrium. Standard dissection to the clavicle is performed, and care is taken to maintain the integrity of the sternoclavicular ligament complex. Circumferential dissection of the medial clavicular metaphysis is usually required in order to mobilize the dislocated fragment. Reduction of the physeal fracture usually requires axial traction and extension of the ipsilateral shoulder with the aid of a reduction clamp on the medial clavicular metaphysis. In some cases, a Freer elevator can be placed between the metaphysis and epiphysis to shoehorn the clavicle from posterior to anterior. Once reduced, the fracture-dislocation is usually stable; however, the reduction is augmented with suture fixation. The sternoclavicular joint capsule should be repaired if disrupted, and the incision should be closed in layers. Postoperatively, the arm is placed in a sling, and range of motion is commenced at 4 weeks. ALTERNATIVES: Alternative management of acute sternoclavicular fracture-dislocation includes closed reduction, plate fixation4, and ligament reconstruction5. RATIONALE: In our experience, closed reduction is often unsuccessful, which is consistent with the experiences reported by other authors2,3. In addition, suture fixation is sufficient and plate fixation is not required because this injury is relatively stable following reduction. Lastly, ligament reconstruction with use of autograft or allograft may be indicated but is more relevant in chronic cases with injury or attenuation of the sternoclavicular ligament complex. Open reduction allows for direct visualization of the fracture reduction, and suture fixation allows for increased stability without the need for hardware or secondary surgical procedures. EXPECTED OUTCOMES: We expect patients to achieve full range of motion and strength without any joint instability as reported by Waters et al.3. IMPORTANT TIPS: There is an inherent risk of vascular injury with open reduction and suture fixation. This risk is mitigated with perioperative planning and consultation with vascular or thoracic surgeons. General surgeons should always be available when these procedures are performed in case of vascular issues or emergencies.It is sometimes difficult to reduce the dislocation, but additional maneuvers allow for controlled reduction of the displaced clavicle, such as using a Freer elevator and serrated clamp.Assessing fracture reduction can be difficult intraoperatively. Including the contralateral sternoclavicular joint in the sterile surgical field can be helpful in assessing fracture reduction and osseous contour.

Utilization and Economic Impact of Posterolateral Fusion and Posterior/Transforaminal Lumbar Interbody Fusion Surgeries in the United States.

STUDY DESIGN: Retrospective database study. OBJECTIVE: To analyze the economic and age data concerning primary and revision posterolateral fusion (PLF) and posterior/transforaminal lumbar interbody fusion (PLIF/TLIF) throughout the United States to improve value-based care and health care utilization. METHODS: The National Inpatient Sample (NIS) database was queried by the International Classification of Diseases, Ninth Revision, Clinical Modification codes for patients who underwent primary or revision PLF and PLIF/TLIF between 2011 and 2014. Age and economic data included number of procedures, costs, and revision burden. The National Inpatient Sample database represents a 20% sample of discharges from US hospitals weighted to provide national estimates. RESULTS: From 2011 to 2014, the annual number of PLF and PLIF/TLIF procedures decreased 18% and increased 23%, respectively, in the Unites States. During the same period, the number of revision PLF decreased 19%, while revision PLIF/TLIF remained relatively unchanged. The average cost of PLF was lower than the average cost of PLIF/TLIF. The aggregate national cost for PLF was more than $3 billion, while PLIF/TLIF totaled less than $2 billion. Revision burden (ratio of revision surgeries to the sum of both revision and primary surgeries) remained constant at 8.0% for PLF while it declined from 3.2% to 2.9% for PLIF/TLIF. CONCLUSION: This study demonstrated a steady increase in PLIF/TLIF, while PLF alone decreased. The increasing number of PLIF/TLIF procedures may account for the apparent decline of PLF procedures. There was a higher average cost for PLIF/TLIF as compared with PLF. Revision burden remained unchanged for PLF but declined for PLIF/TLIF, implying a decreased need for revision procedures following the initial PLIF/TLIF surgery.

National Trends for Primary and Revision Lumbar Disc Arthroplasty Throughout the United States.

STUDY DESIGN: Retrospective database study. OBJECTIVES: Analysis of economic and demographic data concerning lumbar disc arthroplasty (LDA) throughout the United States to improve value-based care and health care utilization. METHODS: The National Inpatient Sample database was queried for patients who underwent primary or revision LDA between 2005 and 2013. Demographic and economic data included total surgeries, costs, length of stay, and frequency of routine discharge. The National Inpatient Sample database represents a 20% sample of discharges from US hospitals weighted to provide national estimates. RESULTS: Primary LDA decreased 86% from 3059 to 420 from 2005 to 2013. The mean total cost of LDA increased 33% from $17 747 to $23 804. The mean length of stay decreased from 2.8 to 2.4 days. The mean routine discharge (home discharge without visiting nursing care) remained constant at 91%. Revision procedures (removal, supplemental fixation, or reoperation at the treated level) declined 30% from 194 to 135 cases over the study period. The mean revision burden, defined as the ratio of revision procedures to the sum of primary and revision procedures, was 12% (range 6% to 24%). The mean total cost of revisions ranged from $12 752 to $22 282. CONCLUSIONS: From 2005 to 2013, primary LDA significantly declined in the United States by 86% despite several studies pointing to improved efficacy and cost-efficiency. This disparity may be related to a lack of surgeon reimbursement from insurance companies. Congruently, the number of revision LDA cases has declined 30%, while revision burden has risen from 6% to 24%.

Trends in resource utilization and rate of cervical disc arthroplasty and anterior cervical discectomy and fusion throughout the United States from 2006 to 2013.

BACKGROUND CONTEXT: The typically accepted surgical procedure for cervical disc pathology has been the anterior cervical discectomy and fusion (ACDF), although recent trials have demonstrated equivalent or improved outcomes with cervical disc arthroplasty (CDA). Trends for these two procedures regarding utilization, revision procedures, and other demographic information have not been sufficiently explored. PURPOSE: The present study aims to provide data regarding ACDF and CDA from 2006 to 2013 in the United States. DESIGN: The present study is a retrospective national database analysis. PATIENT SAMPLE: The present study included 20% sample of discharges from US hospitals, which is weighted to provide national estimates. OUTCOME MEASURES: Functional measures such as national incidence, hospital costs, length of stay (LOS), routine discharge, revision burden, and patient characteristics were used in the present study. METHODS: Patients from the National Inpatient Sample (NIS) database who underwent primary ACDF, revision ACDF, primary CDA, and revision CDA from 2006 to 2013 were included. Demographic and economic data for the procedures' respective International Classification of Diseases, Ninth Revision, Clinical Modification codes were collected. RESULTS: A total of 1,059,403 ACDF and 13,099 CDA surgeries were performed in the United States from 2006 to 2013. The annual number of ACDF increased by 5.7% nonlinearly from 120,617 in 2006 to 127,500 in 2013 (mean per year 132,425; range 120,617-147,966); CDA increased by 190% nonlinearly from 540 in 2006 to 1,565 in 2013 (mean per year 1,637; range 540-2,381). Cervical disc arthroplasty patients were younger and had more private or "other" insurance, including worker's compensation (p<.0001). Mean LOS was longer for ACDF (ACDF 2.3 days vs. CDA 1.5; p<.0001). Routine discharge was higher in the CDA group (CDA 96% vs. ACDF 89%; p-value<.0001). The mean hospital-related cost was more expensive for ACDF (ACDF $16,178 vs. CDA $13,197; p-value=.0007). Cervical disc arthroplasty mean revision burden, defined as the ratio of revision procedures to the sum of primary and revision procedures, was greater (CDA 5.9% vs. ACDF 2.3%, p-value=.01). CONCLUSIONS: Nationally approximately 132,000 ACDFs are done each year compared with only 1,600 CDAs. The number of ACDF surgeries performed far outpaces CDA by a ratio of 81:1 in the United States without a clear direction in the trend for utilization given recent fluctuations. Cervical disc arthroplasty revision burden was more than double compared with the ACDF revision burden (5.9% vs. 2.3%), which was not accounted for by patient baseline demographics. The etiologies of these findings are likely multifactorial and require further research.

Proximodistal Heterogeneity of Hippocampal CA3 Pyramidal Neuron Intrinsic Properties, Connectivity, and Reactivation during Memory Recall.

The hippocampal CA3 region is classically viewed as a homogeneous autoassociative network critical for associative memory and pattern completion. However, recent evidence has demonstrated a striking heterogeneity along the transverse, or proximodistal, axis of CA3 in spatial encoding and memory. Here we report the presence of striking proximodistal gradients in intrinsic membrane properties and synaptic connectivity for dorsal CA3. A decreasing gradient of mossy fiber synaptic strength along the proximodistal axis is mirrored by an increasing gradient of direct synaptic excitation from entorhinal cortex. Furthermore, we uncovered a nonuniform pattern of reactivation of fear memory traces, with the most robust reactivation during memory retrieval occurring in mid-CA3 (CA3b), the region showing the strongest net recurrent excitation. Our results suggest that heterogeneity in both intrinsic properties and synaptic connectivity may contribute to the distinct spatial encoding and behavioral role of CA3 subregions along the proximodistal axis.

Improved specificity of hippocampal memory trace labeling.

Recent studies have focused on the identification and manipulation of memory traces in rodent models. The two main mouse models utilized are either a CreER(T2) /loxP tamoxifen (TAM)- or a tetracycline transactivator/tetracycline-response element doxycycline-inducible system. These systems, however, could be improved to label a more specific population of activated neurons corresponding to behavior. Here, we sought to identify an improved selective estrogen receptor (ER) modulator (SERM) in which we could label an individual memory trace in ArcCreER(T2) mice. We found that 4-hydroxytamoxifen (4-OHT) is a selective SERM in the ArcCreER(T2) × Rosa26-CAG-stop(flox) -channelrhodospin (ChR2)-enhanced yellow fluorescent protein (eYFP) mice. The half-life of 4-OHT is shorter than TAM, allowing for more specificity of memory trace labeling. Furthermore, 4-OHT allowed for context-specific labeling in the dentate gyrus and CA3. In summary, we believe that 4-OHT improves the specificity of memory trace labeling and will allow for refined memory trace studies in the future. © 2015 Wiley Periodicals, Inc.