Low Back Pain: Utilization of Urgent Cares Relative to Emergency Departments

STUDY DESIGN/SETTING

Retrospective study.

OBJECTIVE

To understand why patients utilize emergency departments (EDs) versus urgent care centers for low back pain (LBP).

SUMMARY OF BACKGROUND DATA

LBP is a common reason for ED visits. In the setting of trauma or recent surgery, the resources of EDs may be needed. However, urgent care centers may be appropriate for other cases.

MATERIALS AND METHODS

Adult patients below 65 years of age presenting to the ED or urgent care on the day of diagnosis of LBP were identified from the 2019 PearlDiver M151 administrative database. Exclusion criteria included history of radiculopathy or sciatica, spinal surgery, spinal cord injury, other traumatic, neoplastic, or infectious diagnoses in the 90 days prior, or Medicare insurance. Patient age, sex, Elixhauser comorbidity index, geographic region, insurance, and management strategies were extracted. Factors associated with urgent care relative to ED utilization were assessed using multivariable analysis.

RESULTS

Of 356,284 LBP patients, ED visits were identified for 345,390 (96.9%) and urgent care visits for 10,894 (3.1%). Factors associated with urgent care use relative to the ED were: geographic region [relative to Midwest; Northeast odds ratio (OR): 5.49, South OR: 1.54, West OR: 1.32], insurance (relative to Medicaid; commercial OR: 4.06), lower Elixhauser comorbidity index (OR: 1.28 per two-point decrease), and higher age (OR: 1.10 per decade), female sex (OR: 1.09), and use of advanced imaging (OR: 0.08) within 1 week ( P <0.001 for all).

CONCLUSIONS

Most patients presenting for a first diagnosis of isolated LBP went to the ED relative to urgent care. The greatest drivers of urgent care versus ED utilization for LBP were insurance type and geographic region. Utilization of advanced imaging was higher among ED patients, but rates of surgical intervention were similar between those seen in the ED and urgent care.

Glenohumeral Superior Translation and Subacromial Contract Pressure Are Both Improved With Superior Capsular Reconstruction: A Systematic Review and Meta-analysis of Biomechanical Investigations

PURPOSE

To review cadaveric studies evaluating the biomechanical outcomes of superior capsular reconstruction (SCR) with different graft types for the treatment of irreparable rotator cuff (RTC) tears.

METHODS

PubMed, Cochrane, and Embase were queried in January 2022 to conduct this meta-analysis using the following key words: "superior capsule reconstruction," "superior capsular reconstruction," and "biomechanics." Articles were included if they reported glenohumeral superior translation or subacromial contact pressure following SCR in cadaveric RTC tears. The review adhered to the Preferred Reporting Items for Systematic Reviews and Meta-analyses criteria. Number of shoulders, graft types, and biomechanical outcomes were recorded and analyzed with forest plots.

RESULTS

Twelve studies (95 shoulders) were included in the statistical analysis. There was a significant reduction in glenohumeral superior translation following SCR compared with RTC tear across 10 studies (79 shoulders) with standardized mean difference (SMD) -2.48 mm; confidence interval (CI) -3.28 mm, -1.69 mm. The SMD between fascia lata graft and RTC tear was -3.84 mm (CI -4.82 mm, -2.86 mm) and between dermal allograft and RTC tear was -2.05 mm (CI -3.10 mm, -1.00 mm). There was a significant reduction in subacromial contact pressure following SCR compared with RTC tear across 5 studies (55 shoulders) with SMD -3.49 MPa (CI -4.54 MPa, -2.44 MPa). The SMD between fascia lata graft and RTC tear was -3.21 MPa (CI -5.08 MPa, -1.34 MPa) and between dermal allograft and RTC tear was -3.89 MPa (CI -5.91 MPa, -1.87 MPa).

CONCLUSIONS

Independent of graft type, biomechanical studies suggest that SCR improves glenohumeral superior translation and subacromial contact pressure in comparison with RTC tear at time zero. There was no definitive evidence identified in this study to suggest a biomechanically superior SCR graft option.

CLINICAL RELEVANCE

Investigating the biomechanical outcomes of several graft types for superior capsular reconstruction will help surgeons better understand the efficacies of different graft types for use in superior capsule reconstruction surgery.

Female Patients Undergoing Latarjet Surgery Show Similar 2-Year Secondary Surgery Rates but Greater Risk of Emergency Department Visits Compared With a Matched Cohort of Male Patients

PURPOSE

To evaluate sex-based differences in 30-day postoperative emergency department (ED) visits, 90-day complication rates, and 2-year secondary surgery rates after the Latarjet procedure for the treatment of recurrent shoulder instability.

METHODS

A national administrative claims database was used to identify patients with International Classification of Diseases, Tenth Revision (ICD-10) diagnosis codes for shoulder subluxation or dislocation on the day of first-time stabilization with the Latarjet technique between 2015 and 2021. Male patients were matched 4:1 to female patients based on age, Elixhauser Comorbidity Index (ECI) score, and body mass index class. Rates of 30-day ED visits and 90-day complications were compared between cohorts, and risk factors for ED visits were identified by multivariate regression. The incidence of secondary surgery within 2 years was compared by Kaplan-Meier analysis.

RESULTS

Prior to matching, 1,059 male and 360 female patients met the inclusion and exclusion criteria. Subsequent 4:1 (male-to-female) matching controlling for age, ECI score, and body mass index yielded 694 male and 185 female patients who underwent the Latarjet procedure. The overall incidence of 30-day ED visits was 9.3%, with an incidence of 8.2% for male patients and 13.5% for female patients. On the basis of multivariate logistic regression, these 30-day ED visits were associated with female sex (odds ratio, 1.79; P = .029) and incrementally higher ECI scores; relative to an ECI score of 0, ECI scores of 1 to 2, 3 to 4, and 5 or greater were associated with odds ratios of 5.31 (P = .006), 8.12 (P < .001), and 12.84 (P < .001), respectively. Ninety-day complications occurred in 1.5% of the total cohort, and the incidence was not statistically different between sexes. Overall, 2-year secondary surgery rates were similar between male and female patients (5.1% and 6.7%, respectively; P = .4).

CONCLUSIONS

Female patients undergoing the Latarjet procedure for recurrent shoulder instability showed similar 90-day complication and 2-year secondary surgery rates to a matched cohort of male patients. Female sex, along with ECI score, however, was associated with a greater rate of 30-day ED visits.

LEVEL OF EVIDENCE

Level III, retrospective comparative case series.

Total shoulder arthroplasty in patients with factor V Leiden

BACKGROUND

Anatomic and reverse total shoulder arthroplasty (TSA) are effective treatment options for end-stage glenohumeral osteoarthritis. However, consideration for pre-existing conditions must be taken into account. Factor V Leiden (FVL), the most common inherited thrombophilia, is one such condition that predisposes to a prothrombotic state and may affect perioperative and longer-term outcomes following TSA.

METHODS

Adult patients undergoing primary TSA for osteoarthritis indication were identified in the 2010 through October 2021 PearlDiver M157 database. Patients with or without FVL were matched at a 1:4 ratio based on age, sex, and Elixhauser Comorbidity Index. Ninety-day adverse events and 5-year revision rates were assessed and compared with multivariable logistic regression and rank-log tests, respectively. Finally, the relative use and bleeding/clotting outcomes were assessed based on venous thromboembolic (VTE) prophylactic agents used, with categories defined as (1) warfarin, heparin, or direct oral anticoagulant (DOAC) or (2) aspirin/no prescription found.

RESULTS

Of 104,258 TSA patients, FVL was identified for 283 (0.27%). Based on matching, 1081 patients without FVL and 272 patients with FVL were selected. Multivariable analyses demonstrated that those with FVL displayed independently greater odds ratios (ORs) of deep vein thrombosis (DVT, OR = 9.50, P < .0001), pulmonary embolism (PE, OR = 10.10, P < .0001), and pneumonia (OR = 2.43, P = .0019). Further, these events contributed to the increased odds of aggregated minor (OR = 1.95, P = .0001), serious (OR = 6.38, P < .0001), and all (OR = 3.51, P < .0001) adverse events. All other individual 90-day adverse events, as well as 5-year revision rates, were not different between the study groups. When compared to matched patients without FVL on the same anticoagulant agents, FVL patients on warfarin, heparin, or DOAC agents demonstrated lesser odds of 90-day DVT and PE (OR = 4.25, P < .0001, and OR = 2.54, P = .0065) than those on aspirin/no prescription found (OR = 7.64 and OR = 21.95, P < .0001 for both). Interestingly, those on VTE prophylactic agents were not at greater odds of bleeding complications (hematoma or transfusion).

DISCUSSION AND CONCLUSIONS

TSA patients with FVL present a difficult challenge to shoulder reconstruction surgeons. The current study highlights the strong risk of VTE that was reduced but still significantly elevated for those with stronger classes of VTE chemoprophylaxis. Acknowledging this risk is important for surgical planning and patient counseling, but also noted was the reassurance of similar 5-year revision rates for those with vs. without FVL.

Low Rates of Postoperative Complications and Revision Surgery After Primary Medial Elbow Ulnar Collateral Ligament Repair

Purpose

To evaluate the incidence of early postoperative complications and revision surgery in patients who underwent primary medial ulnar collateral ligament (MUCL) repair with minimum of 2-year follow-up.

Methods

A retrospective review of a national insurance database was conducted to identify patients with MUCL injuries who underwent primary MUCL repair between 2015 to 2020 with minimum 2-year follow-up. Patients >40 years of age and those who had concomitant elbow fractures or dislocations, lateral UCL injures, medial epicondylitis, elbow arthritis, or a history of previous elbow injury/surgery were excluded. The number of patients who underwent a concomitant ulnar nerve procedure (transposition or decompression) during the primary MUCL repair was recorded. Complications within 90 days of surgery and the incidence and timing of subsequent ipsilateral ulnar nerve surgery or revision MUCL surgery were assessed.

Results

A total of 313 patients (63.6% male) were included. The mean age was 20.3 ± 6.9 years, and mean follow-up was 3.7 ± 1.3 years. Concomitant ulnar nerve transposition or decompression was performed in 34.2% (N = 107). The early postoperative complication rate was 7.3% (N = 23). The most common complication was ulnar neuropathy (5.8%, N = 18). Wound complications, elbow stiffness, and medial epicondyle fractures were much less common (N = 5). Sixteen of 18 (88.9%) patients with postoperative ulnar neuropathy underwent transposition or decompression at the time of primary repair. Of these 18 patients, 5 (27.8%) underwent a subsequent ulnar nerve surgery (1 primary and 4 secondary), with the majority occurring within 6 months. The incidence of revision MUCL surgery was low (1.0%, N=3), with all 3 patients undergoing MUCL reconstruction.

Conclusion

There was a low incidence of early postoperative complications (7.3%) and 2-year revision MUCL surgery (1.0%) in young patients who underwent primary MUCL repair with no additional ligamentous, fracture, and dislocation-related diagnoses. All 3 (1.0%) MUCL revisions underwent reconstruction.

Level of Evidence

Level IV, therapeutic case series.

Trends in and Factors Associated With Surgical Management for Closed Clavicle Fractures

INTRODUCTION

Clavicle fractures are common and have historically been managed nonsurgically. Over time, there are increasing surgical considerations for such injuries. Nonetheless, trends over the past decade are not well characterized.

METHODS

Adult patients presenting for first diagnosis of clavicle fractures were identified from the 2010 to 2020 PearlDiver M151 database. Patients were defined to have undergone surgical management if they received clavicular open reduction and internal fixation within 90 days after fracture diagnosis. Patient age, sex, Elixhauser Comorbidity Index (ECI), geographic region, insurance coverage, fracture anatomic location, and polytraumatic diagnoses were extracted. Factors independently associated with surgical management versus nonsurgical management were assessed with multivariable analysis.

RESULTS

Overall, 50,980 patients with clavicle fractures were identified of whom 6,193 (12.1%) were managed surgically. This proportion increased significantly over the study period (7.4% in 2015 to 13.9% in 2020, P < 0.001). Independent predictors of surgical management included fracture diagnosis in 2020 (versus 2015, odds ratio [OR] 2.36), anatomic location (relative to lateral end, shaft OR 1.84 and sternal OR 3.35), and Midwest region of service (OR 1.26, relative to South) (P < 0.001 for all).

DISCUSSION

A small but increasing minority of patients with clavicle fractures are managed surgically. Clinical factors and nonclinical factors were associated with surgical management.

Rates of subsequent surgeries after meniscus repair with and without concurrent anterior cruciate ligament reconstruction

OBJECTIVES

The purpose of this study was to compare the rates of secondary knee surgery for patients undergoing meniscus repair with or without concurrent anterior cruciate ligament reconstruction (ACLr).

METHODS

Utilizing a large national database, patients with meniscal repair with or without concurrent arthroscopic ACLr were identified. The two cohorts were then queried for secondary surgical procedures of the knee within the following 2 years. Frequency, age distribution, rates of secondary surgery, and type of secondary procedures performed were compared.

RESULTS

In total, 1,585 patients were identified: meniscus repair with ACLr was performed for 1,006 (63.5%) and isolated meniscal repair was performed for 579 (36.5%). Minimum of two year follow up was present for 487 (30.7% of the overall study population). Secondary surgery rates were not significantly different between meniscus repair with concurrent ACLr and isolated meniscus repairs with an overall mean follow up of 13 years (1.5-24 years) (10.6% vs. 13.6%, p = 0.126). For the 2 year follow up cohort, secondary surgery rates were not significantly different (19.3% vs. 25.6%, p = 0.1098). There were no differences in survivorship patterns between the two procedures, both in the larger cohort (p = 0.2016), and the cohort with minimum 2-year follow-up (p = 0.0586).

CONCLUSION

The current study assessed secondary surgery rates in patients undergoing meniscus repair with or without concurrent ACLr in a large patient database. Based on this data, no significant difference in rates of secondary knee surgery was identified.

Adverse Events After Ankle Fracture Open Reduction Internal Fixation Among Patients With and Without Documented Cannabis and Tobacco Use

BACKGROUND

Ankle fractures are common orthopaedic injuries that may be indicated for open reduction internal fixation (ORIF). Although the negative impact of tobacco use on perioperative outcomes of ankle fracture ORIF has been described, the potential impact of cannabis use on related outcomes is not as well established.

METHODS

Retrospective database study of adult patients undergoing ankle ORIF for closed, isolated, ankle fractures from the 2010-2021 Q1 PearlDiver M151 data set. Subcohorts without and with cannabis and/or tobacco use were identified based on coding and matched based on patient age, sex, and Elixhauser Comorbidity Index (ECI) scores to yield groups of nonusers, tobacco users, tobacco and cannabis users, and cannabis users. Ninety-day adverse events were assessed between matched subcohorts with multivariable logistic regression controlling for age, sex, and ECI.

RESULTS

A total of 149 289 patients met study inclusion criteria for whom tobacco only use was documented for 14 989 (10.0%), tobacco and cannabis use for 2726 (1.8%), and cannabis only use for 867 (0.6%). Matching yielded 823 for each group. On multivariable analyses, isolated tobacco users were at higher odds of 90-day urinary tract infections (UTIs) (odds ratio [OR] 2.64), minor adverse events (OR 2.33), all-cause adverse events (OR 2.17), readmissions (OR 1.85), and severe adverse events (OR 1.84). Tobacco and cannabis comorbid users were at a marginally higher odds of 90-day UTI (OR 2.82), minor adverse events (OR 2.51), readmissions (OR 2.39), and any adverse events (OR 2.22). Cannabis only users were not at greater odds of 90-day adverse events relative to nonusers.

CONCLUSION

Patients with tobacco use (alone or with cannabis) were at greater odds of 90-day adverse events following ankle fracture ORIF, but cannabis only users were not.

LEVEL OF EVIDENCE

Level III, Retrospective database study.

Urgent Care Versus Emergency Department Utilization for Foot and Ankle Fractures

INTRODUCTION

Foot and ankle fractures are common injuries for which patients may need urgent evaluation and care. Many such injuries are managed in emergency departments (EDs), but urgent care facilities may sometimes be an appropriate setting. Understanding which foot and ankle fractures are managed at which facility might help define care algorithms, improve patient experience, and suggest directions for containing costs.

METHODS

This retrospective cohort study used the 2010 to 2020 M151 PearlDiver administrative database. Adult patients less than 65 years old presenting to EDs and urgent care facilities for foot and ankle fractures were identified using ICD-9 and ICD-10 diagnosis codes, excluding polytrauma, and Medicare patients. Patient/injury variables associated with urgent care utilization relative to ED utilization and utilization trends of urgent care relative to ED were assessed with univariable and multivariable analyses.

RESULTS

From 2010 to 2020, 1,120,422 patients with isolated foot and ankle fractures presented to EDs and urgent care facilities. Urgent care visits evolved from 2.2% in 2010 to 4.4% in 2020 (P , 0.0001). Independent predictors of urgent care relative to ED utilization were defined. In decreasing odds ratios (ORs), these were insurance (relative to Medicaid, commercial OR 8.03), geographic region (relative to Midwest, Northeast OR 3.55, South OR 1.74, West OR 1.06), anatomic location of fracture (relative to ankle, forefoot OR 3.45, midfoot 2.20, hindfoot 1.63), closed fracture (OR 2.20), female sex (OR 1.29), lower ECI (OR 1.11 per unit decrease), and younger age (OR 1.08 per decade decrease) (P , 0.0001 for all).

DISCUSSION

A small but increasing minority of patients with foot and ankle fractures are managed in urgent care facilities relative to EDs. While patients with certain injury types were associated with increased odds of urgent care relative to ED utilization, the greatest predictors were nonclinical, such as geographic regions and insurance type, suggesting areas for optimizing access to certain care pathways.

LEVEL OF EVIDENCE

III.

An Epidemiological Study of Cell Phone–Related Injuries of the Hand and Wrist Reported in United States Emergency Departments From 2011 to 2020

Purpose

Increasing ownership and use of mobile phones has been recently linked to reports of hand and wrist pain from overuse, as well as more serious injuries related to distracted behaviors, such as falls and texting while driving. We describe the epidemiology of hand and wrist injuries presenting to US emergency departments from 2011 to 2020, which were associated with cell phone use using the Consumer Product Safety Commission's National Electronic Injury Surveillance System.

Methods

The National Electronic Injury Surveillance System database was queried for treatment records from 2011 through to 2020 for all cell phone-related injuries of the lower arm, wrist, hand, and fingers. Using parameters provided by the National Electronic Injury Surveillance System database, there were 1,213 unique cases, yielding a total weighted estimate of 50,487 national cases presenting to emergency departments in the United States.

Results

Between 2011 and 2020, the weighted estimate of annual cell phone-related injuries ranged from 3,389 to 7,320 cases. Falls were the most common cause of injury, accounting for 29.8% of estimated cases. The most common types of injuries were lacerations (22.3%). The national estimate of cell phone-related injury was the highest in the age range of 11-20 years (26.4%), followed by 21-30 years (22.2%). Women were affected more frequently than men (59.6% vs 40.4%).

Conclusions

Upper extremity injuries related to cell phone use represent an increasing burden of disease to the US healthcare system. Raising awareness regarding cell phone-related injuries and in-home fall-prevention strategies, especially among elderly individuals, should be considered as means of decreasing the number of such injuries. Strategies for decreasing the burden of cell phone-related injuries occurring as a result of falls among teenagers and young adults should focus on minimizing distractions while using a cell phone. Limitations of the study include inaccuracies related to probability-weighted case estimation and limitations in reporting injuries.

Clinical relevance

Knowledge of the burden of upper extremities injuries associated with this common handheld device can help to both raise awareness of this issue, as well as to potentially inform injury-prevention strategies.

Comparative Success of Repair Versus Reconstruction for Knee Extra-articular Ligament Injuries

Background

Surgical techniques and associated outcomes in treating acute and chronic extra-articular ligament knee injuries are in evolution, and there is question as to whether repair or reconstruction is optimal.

Purpose/Hypothesis

The purpose of this study was to compare the subsequent surgery rate between surgical repair versus reconstruction for all extra-articular ligament injuries of the knee utilizing a large database. Our hypothesis was that overall surgical repair of both lateral and medial extra-articular knee injuries would have a higher revision rate than those treated by reconstruction.

Study Design

Cohort study; Level of evidence, 3.

Methods

The PearlDiver Mariner data set (2010-2019), with 122 million patients, was utilized to generate 2 patient cohorts: those who underwent surgical repair and those who underwent surgical reconstruction of a knee extra-articular ligament injury. All patients had a minimum of 2 years follow-up. Rates of concomitant or subsequent cruciate ligament reconstruction and rates of secondary procedures were assessed and compared between the 2 cohorts.

Results

In total, 3563 patients were identified: extra-articular ligament reconstruction was performed for 2405 (67.5%), and repair was performed for 1158 (32.5%). Cruciate ligament reconstruction was performed for 986 (27.7%), of which 888 of 986 (90.1%) were performed on the same day as their extra-articular ligament procedure. At 2-year follow-up, the reconstruction cohort had higher rates of revision surgery compared with the repair cohort (8.2% vs 2.5%; P < .001).

Conclusion

Using a large national database, knee extra-articular ligamentous reconstructions (those on both the lateral and the medial side) had a 3.3 times higher rate of revision surgery compared with repair at 2-year follow-up. Further study is needed to investigate the causes leading to revision surgery and to determine the optimal surgical treatment for both medial and lateral extra-articular knee ligament injuries.

Comparing Venous Thromboembolism Prophylactic Agents After Hip Fracture Surgery: A National Database Study

INTRODUCTION

Although the use of venous thromboembolism (VTE) chemoprophylaxis has markedly reduced VTE rates after hip fracture surgery, few studies have directly compared the efficacy of different anticoagulant agents in this setting. The purpose of this study was to compare outcomes of Lovenox, Eliquis, or Coumadin as VTE prophylaxis after hip fracture surgery.

METHODS

The PearlDiver MHip national database was queried for patients older than 60 years undergoing first-time hip fracture surgery with no concurrent pelvic or distal femoral fractures. Prescriptions for Lovenox, Eliquis, or Coumadin were identified. Univariate and multivariate analyses of patient characteristics, 90-day incidences of VTE, adverse events, and readmissions were compared. Odds ratios (ORs) were calculated, and significance was set at P < 0.01 based on Bonferroni adjustment.

RESULTS

A total of 11,384 patients were identified, with the Lovenox used for 6835 patients (60.0%), Eliquis for 1092 patients (9.6%), and Coumadin for 3457 patients (30.4%). The prevalence of 90-day VTE in the Lovenox, Eliquis, and Coumadin groups was 3.1%, 3.8%, and 5.0%, respectively (P < 0.001). Multivariate analyses adjusting for demographic and comorbidity profiles were conducted with Lovenox as the referent. Those on Eliquis had significantly lower transfusions (OR 0.52, P = 0.005), but similar rates of other outcomes including VTE (P > 0.01). Conversely, patients on Coumadin had significantly greater odds of any adverse event (OR 1.18, P < 0.001) and VTE (OR 1.58, P < 0.001).

DISCUSSION

In evaluating Lovenox, Eliquis, and Coumadin as VTE chemoprophylactic agents after hip fracture surgery in anticoagulant-naïve patients, Lovenox and Eliquis had similar 90-day VTE, whereas patients on Coumadin had greater odds of 90-day VTE. Interestingly, patients on Eliquis had nearly two-fold lower odds of transfusions compared with patients on Lovenox. Although consensus on the optimal VTE prophylactic agent after hip fracture surgery does not exist, Eliquis and Lovenox may be comparable options and seem to be more effective than Coumadin.

Pharmacological Attenuation of Electrical Effects in a Model of Compression Neuropathy

BACKGROUND

Peripheral nerve compression and entrapment can be debilitating. Using a validated animal model of peripheral nerve compression, we examined the utility of 2 drugs approved for other uses in humans, 4-aminopyridine (4-AP) and erythropoietin (EPO), as treatments for surgically induced ischemia and as adjuvants to surgical decompression.

METHODS

Peripheral nerve compression was induced in wild-type mice by placing an inert silicone sleeve around the sciatic nerve. Decompression surgery was performed at 6 weeks with mice receiving 4-AP, EPO, or saline solution either during and after compression or only after decompression. A nerve conduction study and morphometric analyses were performed to compare the extent of the injury and the efficacy of the therapies, and the findings were subjected to statistical analysis.

RESULTS

During peripheral nerve compression, there was a progressive decline in nerve conduction velocity compared with that in sham-treatment animals, in which nerve conduction velocity remained normal (∼55 m/s). Mice treated with 4-AP or EPO during the compression phase had significantly smaller declines in nerve conduction velocity and increased plateau nerve conduction velocities compared with untreated controls (animals that received saline solution). Histomorphometric analyses of newly decompressed nerves (i.e., nerves that underwent decompression on the day that the mouse was sacrificed) revealed that both treated groups had significantly greater proportions of large (>5-µm) axons than the untreated controls. Following surgical decompression, all animals recovered to a normal baseline nerve conduction velocity by day 15; however, treatment significantly accelerated improvement (in both the 4-AP and the EPO group), even when it was only started after decompression. Histomorphometric analyses at 7 and 15 days following surgical decompression revealed significantly increased myelin thickness and significantly greater proportions of large axons among the treated animals.

CONCLUSIONS

Both the 4-AP and the EPO-treated group demonstrated improvements in tissue architectural and electrodiagnostic measurements, both during and after peripheral nerve compression, compared with untreated mice.

CLINICAL RELEVANCE

Peripheral nerve decompression is one of the most commonly performed procedures in orthopaedic surgery. We believe that there is reason for some optimism about the translation of our findings to the clinical setting. Our findings in this murine model suggest that 4-AP and EPO may lessen the effects of nerve entrapment and that the use of these agents after decompression may speed and perhaps otherwise optimize recovery after surgery.