Risk Factors for Rescue Opioid Prescription After Cubital Tunnel Surgery.

BACKGROUND: Concerns regarding the ongoing opioid epidemic have led to heightened scrutiny of postoperative opioid prescribing patterns for common orthopedic surgical procedures. This study investigated patient- and procedure-specific risk factors for additional postoperative opioid rescue prescriptions following ambulatory cubital tunnel surgery. METHODS: A retrospective review was performed of patients who underwent cubital tunnel surgery at 2 academic medical centers between June 1, 2015 and March 1, 2020. Patient demographics, comorbidities, prior opioid history, and surgical variables were recorded. The primary outcome was postoperative rescue opioid prescription. Univariate and bivariate statistical analyses were performed. RESULTS: Two hundred seventy-four patients were included, of whom 171 (62%) underwent in situ ulnar nerve decompression and 103 (38%) underwent ulnar nerve decompression with anterior transposition. The median postoperative opioid prescription amount was 90 morphine equivalent units (MEU) for the total cohort, 77.5 MEU for in situ ulnar nerve decompression, and 112.5 MEU for ulnar nerve decompression with transposition. Twenty-two patients (8%) required additional rescue opioid prescriptions postoperatively. Female sex, fibromyalgia, chronic opioid use, chronic pain diagnosis, and recent opioid were associated with the need for additional postoperative rescue opioid prescriptions. CONCLUSIONS: While most patients do not require additional rescue opioid prescriptions after cubital tunnel surgery, chronic pain patients and patients with pain sensitivity syndromes are at risk for requiring additional rescue opioid prescriptions. For these high-risk patients, preoperative collaboration of a multidisciplinary team may be beneficial for developing a perioperative pain management plan that is both safe and effective.

Retrograde Intramedullary Nailing Versus Locked Plating for Extreme Distal Periprosthetic Femur Fractures: A Multicenter Retrospective Cohort Study.

OBJECTIVES: To compare clinical and radiographic outcomes after retrograde intramedullary nailing (rIMN) versus locked plating (LP) of "extreme distal" periprosthetic femur fractures, defined as those that contact or extend distal to the anterior flange. DESIGN: Retrospective review. SETTING: Eight academic level I trauma centers. PATIENT SELECTION CRITERIA: Adult patients with periprosthetic distal femur fractures at or distal to the anterior flange (OTA/AO 33B-C[VB1]) treated with rIMN or LP. OUTCOME MEASURES AND COMPARISONS: The primary outcome was reoperation to promote healing or to treat infection (reoperation for elective removal of symptomatic hardware was excluded from this analysis). Secondary outcomes included nonunion, delayed union, fixation failure, infection, overall reoperation rate, distal femoral alignment, and ambulatory status at final follow-up. Outcomes were compared between patients treated with rIMN or LP. RESULTS: Seventy-one patients treated with rIMN and 224 patients treated with LP were included. The rIMN group had fewer points of fixation in the distal segment (rIMN: 3.5 ± 1.1 vs. LP: 6.0 ± 1.1, P < 0.001) and more patients who were allowed to weight-bear as tolerated immediately postoperatively (rIMN: 45%; LP: 9%, P < 0.01). Reoperation to promote union and/or treat infection was 8% in the rIMN group and 16% in the LP group ( P = 0.122). There were no significant differences in nonunion ( P > 0.999), delayed union ( P = 0.079), fixation failure ( P > 0.999), infection ( P = 0.084), or overall reoperation rate ( P > 0.999). Significantly more patients in the rIMN group were ambulatory without assistive devices at final follow-up (rIMN: 35%, LP: 18%, P = 0.008). CONCLUSIONS: rIMN of extreme distal periprosthetic femur fractures has similar complication rates compared with LP, with a possible advantage of earlier return to weight-bearing. Surgeons can consider this treatment strategy in all fractures with stable implants and amenable prosthesis geometry, even extreme distal fractures. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Do Socioeconomic Factors Affect Symptom Duration and Disease Severity at Presentation for Cubital Tunnel Syndrome?

BACKGROUND: Socioeconomic factors have been implicated in delayed presentation for compressive neuropathies of the upper extremity. Our article seeks to elucidate the effect of socioeconomic factors on self-reported symptom duration and objective disease severity at presentation for cubital tunnel syndrome. METHODS: This retrospective cohort study included 207 patients with surgical management of cubital tunnel syndrome at 2 institutions between June 1, 2015, and March 1, 2020. Exclusion criteria included age under 18 years, revision surgery, lack of preoperative electrodiagnostic studies, and concurrent additional surgeries. Response variables were self-reported symptom duration, time from presentation to surgery, McGowan grade, and electrodiagnostic measures. Explanatory variables included age, sex, white race, diabetes mellitus, depression, anxiety, and the Distressed Communities Index. RESULTS: Symptom duration was associated with nonwhite race, and time from presentation to surgery was associated with insurance provider. More clinically severe disease was associated with older age, male sex, and not having carpal tunnel syndrome. Nonrecordable sensory nerve action potential latency was associated with older age, higher body mass index, male sex, diabetes mellitus, and unemployment. Nonrecordable conduction velocities were associated with older age, and having fibrillations at presentation was associated with older age, male sex, and unemployment. CONCLUSIONS: Economic distress is not associated with self-reported symptom duration, time from presentation to surgery, or presenting severity of cubital tunnel syndrome. White patients presented with shorter self-reported symptom duration. Insurance type was associated with delay from presentation to surgery. Older age and male sex were risk factors for more clinically severe disease at presentation.

Does Screw Order Matter? A Technique Tip to Prevent Loss of Fracture Reduction during Surgical Fixation of Lateral Malleolus Fractures.

When obtaining surgical fixation of lateral malleolus fractures, a cortical lag screw is commonly used to obtain anatomic reduction. Subsequently, a neutralization plate is applied. Slight loss of fracture reduction after plate placement occasionally occurs. Although this is frequently attributed to poor bone quality or suboptimal initial lag screw fixation, a frequently overlooked factor is screw order when applying the neutralization plate. The purpose of this technique tip is to highlight the biomechanical rationale behind this loss of reduction and advocate a specific screw order for lateral malleolus fixation.

Does the Surgical Assistant Influence Perioperative Outcomes Surrounding Cubital Tunnel Surgery?

Background: Ulnar neuropathy at the elbow is the second most common upper extremity compressive neuropathy and surgical treatment often involves surgical trainee involvement. The primary aim of this study is to determine the effect of trainees and surgical assistants on outcomes surrounding cubital tunnel surgery. Methods: This retrospective study included 274 patients with cubital tunnel syndrome who underwent primary cubital tunnel surgery at two academic medical centres between 1 June 2015 and 1 March 2020. The patients were divided into four main cohorts based on primary surgical assistant: physician associates (PA, n = 38), orthopaedic or plastic surgery residents (n = 91), hand surgery fellows (n = 132), or both residents and fellows (n = 13). Exclusion criteria included patient age <18 years, revision surgery as the index procedure, prior traumatic ulnar nerve injury and concurrent procedures not related to cubital tunnel surgery. Demographics, clinical variables and perioperative findings were collected through chart reviews. Univariate and bivariate analyses were performed, and p < 0.05 was considered significant. Results: Patients in all cohorts had similar demographic and clinical characteristics. There was a significantly higher rate of subcutaneous transposition in the PA cohort (39.5% PA vs. 13.2% Resident vs. 19.7% Fellow vs. 15.4% Resident + Fellow). Presence of surgical assistants and trainees had no association with length of surgery, complications and reoperation rates. Although male sex and ulnar nerve transposition were associated with longer operative times, no explanatory variables were associated with complications or reoperation rates. Conclusions: Surgical trainee involvement in cubital tunnel surgery is safe and has no effect on operative time, complications or reoperation rates. Understanding the role of trainees and measuring the effect of graduated responsibility in surgery is important for medical training and safe patient care. Level of Evidence: Level III (Therapeutic).

Complications and timing of soft tissue coverage after complete articular, open tibial plateau fractures.

PURPOSE: Complete articular tibial plateau fractures are typically high-energy injuries associated with significant soft tissue trauma. The primary aim of this study was to evaluate the incidence of wound complications and need for soft tissue coverage after open, complete articular tibial plateau fractures. The secondary aim was to study the effect of timing of fixation and timing of flap coverage on deep infection rates in these injuries. METHODS: This was a retrospective cohort study of consecutive patients > 18 years undergoing ORIF of a Bicondylar Tibial Plateau (BTP) fracture between 2001 and 2018. Surgical data were recorded for open fractures including number of debridements, timing of definitive ORIF and soft tissue coverage relative to injury. Primary outcomes included rates of deep infection and unplanned reoperation. RESULTS: 508 AO/OTA 41C BTP fractures were identified, with 51 open fractures included in 50 patients with a mean (SD) age 45.7 (12.3) years and a mean (SD) follow up of 4.3 (3.8) years. There were 20 cases of deep infection, unplanned reoperation occurred in 26 cases. The majority of cases (28 fractures) had initial external fixation placed, while 24 had ORIF at the initial debridement. Twelve patients had a planned flap for definitive closure on average of 6.4 days (SD 3.9) after injury, 14 required a flap for wound complications. Among patients with IIB and C injuries, rates of deep infection (5/6 vs 1/6, p = 0.02) and reoperation (5/7 vs 2/6, p = 0.08) were higher in patients treated with flap coverage >7 days from injury compared to early flap coverage. There were no differences in complication rates between early (<24hrs) and delayed fixation. CONCLUSIONS: Complete articular, open tibial plateau fractures are associated with high rates of complications. Time to flap coverage of seven days or more was a significant predictor of deep infection and unplanned reoperation in this cohort. Patients should be counseled about the high rate of unplanned reoperation and definitive soft tissue coverage should be accomplished within a week of injury whenever possible.

Factors Associated With Implant Removal Following Plate-and-Screw Fixation of Isolated Metacarpal Fractures.

PURPOSE: The incidence of and associated risk factors for implant removal following the plate-and-screw fixation of metacarpal shaft fractures have not been well described. The primary objective of our study was to identify implant-related radiographic parameters associated with implant removal in patients treated with the plate-and-screw fixation of isolated, displaced metacarpal fractures at 2 years of follow-up. The secondary objective of our study was to identify patient-related factors associated with implant removal. METHODS: A retrospective study of all patients who underwent open treatment of a metacarpal fracture with a plate-and-screw construct from January 1, 2000, to April 30, 2019, at 2 level-1 trauma centers was conducted. After the application of exclusion criteria, we identified 138 patients with a single isolated metacarpal fracture of a nonthumb digit treated with open reduction and internal fixation using a plate-and-screw construct. Our study endpoint was the removal of the plate-and-screw construct or a minimum of 2 years of follow-up without the removal of the hardware. Twenty-three patients achieved our study endpoint as determined using their electronic medical records, and 58 additional patients were reached via telephone to confirm their implant removal status. A bivariate analysis was used to screen for factors associated with implant removal, and variables significant in the bivariate screen were included in a multivariable stepwise logistic regression model. RESULTS: Twenty-three out of 81 patients (28%) in our final cohort underwent implant removal by the final follow-up visit. In the logistic regression analysis, the distance between the plate and metacarpophalangeal joint, the distance between the plate and carpometacarpal joint, and active smoking were independently associated with implant removal. CONCLUSIONS: The proximity of metacarpal plates to adjacent joints is associated with subsequent implant removal. Patients may be counseled about the higher risk of implant removal when periarticular metacarpal plating is performed. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognosis IV.

Screw-only fibular construct for Weber B ankle fractures: A retrospective clinical and cost comparison to assess feasibility for resource-limited settings.

INTRODUCTION: Ankle fractures are one of the most common injuries sustained worldwide, with the majority being isolated lateral malleolus fractures. The majority of the world's population live in Low and Middle Income Countries (LMIC), where implant cost may limit surgical treatment of ankle fractures. We investigate if Weber B ankle fractures could be effectively treated with a lower-cost technique using two screws between the fibula and the tibia to neutralize an interfragmentary lag screw. METHODS: After IRB approval, consecutive patients from January 1, 2020 to December 31, 2020 with Weber-B ankle fractures were treated using AO technique (AOT) with plate osteosynthesis neutralizing an interfragmentary screw. Syndesmotic injuries, as well as injuries to the medial malleolus or foot were treated according to the surgeon's preferences. From January 1, 2021 to December 31, 2021 these injuries were treated with a screw-only technique (SOT) with two fibula pro tibia screws to neutralize an interfragmentary screw. Patient demographics including age, sex, BMI, smoking status, associated rheumatoid arthritis, and associated diabetes mellitus were recorded. The primary outcome variable was a stable radiographic mortise at six weeks post-surgery, secondary outcome variables included clinical union, infection, hardware removal, and implant cost for lateral malleolar fixation charged to the hospital. RESULTS: Seventeen AOT and 10 SOT constructs were included. Demographic characteristics were similar between groups. All fractures maintained a stable mortise with clinical union at 6 weeks without infection. There was a statistically significant difference in hardware removal (17.6% AOT, 50% SOT, p = 0.012). The average implant cost to the hospital of the lateral malleolar fixation was significantly less in the SOT group ($592 (SD $229)), compared to the AOT group ($1,949.97 (SD $562)), (p < 0.0001). CONCLUSION: We introduce proof of concept of a novel lower-cost fixation strategy for Weber B ankle fractures that maintained a stable mortise with clinical union at six weeks post-surgery. However, there was a significantly higher rate of hardware removal following fixation with a screw-only construct.

Does distance from joint line influence complications after distal femur fractures in native and periprosthetic knees?

BACKGROUND: Distal femur fractures are projected to increase in incidence secondary to an aging population and growing utilization of total knee arthroplasty. Surgical management is the standard of care, but optimal treatment for far distal fractures is still unclear. Our study investigates if there are distal femur fractures too distal to be treated with lateral locked plating in periprosthetic fractures. METHODS: One hundred and ten consecutive patients treated with locked plating for distal femur fractures around a total knee replacement were identified using CPT codes. Fractures were classified by length of the distal fracture segment and Su classification. Complications studied were nonunion, malunion, infection, further fracture related surgery, readmission within 90 days, and mortality within 1 year of surgery. Sixty six fractures met inclusion criteria of 180 days of follow-up or sustaining a complication prior to180 days. RESULTS: The size of the distal fracture segment and Su classification did not correlate with increased complication rate in periprosthetic distal femur fractures. CONCLUSIONS: There was no difference between complications following lateral locked plating of distal femur fractures based on the size of the distal fracture segment in periprosthetic fractures. Lateral locked plating is an effective treatment modality for these fractures regardless of how distal the fracture extends.

Early Weight Bearing after Distal Femur Fracture Fixation.

OBJECTIVES: To assess outcomes following early weight bearing after distal femur fracture fixation with locked lateral plating. DESIGN: Retrospective cohort study. SETTING: Two Level 1 Academic Trauma Centers. PATIENTS/PARTICIPANTS: Patients 18 years and older with distal femur fractures treated with locked lateral plating. INTERVENTION: Early full weight bearing (defined as less than 30 days from date of surgery) versus restricted post-operative weight bearing. MAIN OUTCOME MEASUREMENTS: Composite complication comprising malunion, nonunion, surgical site infection, re-admission, or death. RESULTS: 270 distal femur fractures were reviewed, with 165 meeting inclusion criteria. 21 patients had been allowed early full weight bearing. Fractures were divided into two groups based on when full weight bearing was allowed post-operatively. The two groups had similar fractures as determined by the distribution of AO distal femur fracture and Su periprosthetic femur fracture classifications. The early weight bearing group was significantly older and more comorbid. Despite being older, more comorbid, and allowed early full weight bearing on their fracture fixation construct, there was no difference in the rate of composite complications between groups. CONCLUSION: Our data contributes to the small, but growing body of literature that has found no increased rate of fracture related complications in surgically treated distal femur fractures allowed early post-operative weight bearing. LEVEL OF EVIDENCE: Therapeutic Level III Study.

Hematoma Formation After Hip Corticosteroid Injection in a Patient with Chronic Myelomonocytic Leukemia: A Case Report.

CASE: We present a 70-year-old woman with history of chronic myelomonocytic leukemia with a right thigh hematoma after a corticosteroid hip injection. Aspiration of the hematoma was attempted, but she developed a significant transfusion requirement with paresthesias in a lateral femoral cutaneous nerve distribution, prompting transfer. Imaging demonstrated no active extravasation, and she was managed conservatively. At 8-month follow-up, she had a persistent consolidated hematoma on the right side, and she subsequently died of complications of her cancer. CONCLUSION: This case demonstrates an unusual complication from a common nonoperative modality, as well as important coagulopathies that must be considered in patients with leukemia.

Fixed (Congenital) Patellar Dislocation.

Congenital dislocation of the patella is a rare condition characterized by lateral dislocation of the patella that is irreducible without surgical correction. Although there is no clear inheritance pattern, it is associated with several congenital syndromes. Patients often demonstrate flexion contracture, loss of active knee extension, increased tibial external rotation, and absent patella in the trochlea. Treatment requires surgical management and is comprised of lateral release, medial stabilization, quadriceps lengthening, and distal realignment. Results are generally favorable after treatment; persistent flexion contracture and redislocation are the most common complications. Further study is needed to define the optimal timing and treatment strategy for this uncommon condition.

What Are the Functional Outcomes and Pain Scores after Medial Clavicle Fracture Treatment?

BACKGROUND: Medial clavicle fractures are uncommon, occurring in older and multiply injured patients. The management of these fractures and the factors that predispose toward poor outcomes are controversial. Furthermore, the functional outcomes of treatment are not well characterized or correlated with fracture patterns. QUESTIONS/PURPOSES: (1) To determine minimum 1-year functional outcomes using QuickDASH scores and pain scores after medial clavicle fractures and (2) to identify factors associated with these outcome variables. METHODS: In an institutional review board-approved, retrospective study, we identified adult patients with medial clavicle fractures at two tertiary care referral centers in a single metropolitan area in the United States from January 2010 to March 2019. Our initial query identified 1950 patients with clavicle fractures, from which 74 adult patients with medial clavicle fractures and at least 1 year of follow-up were identified. We attempted to contact these eligible patients by telephone for functional outcomes and pain scores. Twenty-six patients were deceased according to the most recent Social Security Death Index data and public obituaries, three declined participation, and 14 could not be reached, leaving 42% of the total (31 of 74) and 65% (31 of 48) of living patients included in the analysis. Demographic characteristics, fracture characteristics, and clinical and radiographic union as assessed by plain radiography and CT were collected through record review. Twenty-nine patients were treated nonoperatively and two patients underwent open reduction internal fixation. Sixty-eight percent (21 of 31) of the included patients also had radiographic follow-up at least 6 weeks postoperatively; two patients had persistent nonunion at a mean of 5 ± 3 years after injury. Our primary response variable was the QuickDASH score at a minimum of 1 year (median [range] 5 years [2 to 10]). Our secondary response variable was the pain score on a 10-point Likert scale. A bivariate analysis was performed to identify factors associated with these response variables. The following explanatory variables were studied: age, gender, race, dominant hand injury, employment status, manual labor occupation, primary health insurance, social deprivation, BMI, diabetes mellitus, smoking status, American Society of Anesthesiologists physical status classification, Charlson Comorbidity Index, nonisolated injury, high-energy mechanism of injury, nondisplaced fracture, fracture comminution, superior-inferior fracture displacement, medial-lateral fracture shortening, and surgical treatment of the medial clavicle fracture. RESULTS: The mean QuickDASH score was 12 ± 15, and the mean pain score was 1 ± 1 at a mean of 5 ± 3 years after injury. The mortality rate of the cohort was 15% (11 of 74) at 1 year, 22% (16 of 74) at 3 years, and 34% (25 of 74) at 5 years after injury. With the numbers available, no factors were associated with the QuickDASH score or pain score, but it is likely we were underpowered to detect potentially important differences. CONCLUSION: Medial clavicle fractures have favorable functional outcomes and pain relief at minimum 1-year follow-up among those patients who survive the trauma, but a high proportion will die within 3 years of the injury. This likely reflects both the frailty of a predominantly older patient population and the fact that these often are high-energy injuries. The outcome measures in our cohort were not associated with fracture displacement, shortening, or comminution; however, our sample size was underpowered on these points, and so these findings should be considered preliminary. Further studies are needed to determine the subset of patients with this injury who would benefit from surgical intervention. LEVEL OF EVIDENCE: Level IV, therapeutic study.

The Impact of Cervical Spinal Muscle Degeneration on Cervical Sagittal Balance and Spinal Degenerative Disorders.

STUDY DESIGN: This is a retrospective analysis of kinematic magnetic resonance images (kMRI). OBJECTIVE: To assess the association of cervical paraspinal muscle with cervical sagittal balance and degenerative spinal disorders. SUMMARY OF BACKGROUND DATA: Although the effects of spinal disorders and cervical imbalance on patient's symptoms have been well described, the relationship of the cervical muscle quality and volume to cervical imbalance or spinal disorders is not well established. MATERIALS AND METHODS: In total, 100 kMRI taken in a neutral weight-bearing position were analyzed. The adjusted cross-sectional area ratio (aCSA ratio: the value of muscle CSA divided by the vertebral CSA) and fat infiltration ratio of the transversospinalis muscles at C4 and C7 vertebral levels were measured using axial slice of kMRI. The correlation with cervical balance parameters [Oc-C2 angle, C2-C7 angle, C7-T1 angle, C7 slope, T1 slope, cranial tilt, cervical tilt, thoracic inlet angle (TIA), and neck tilt] and cervical degenerative disorders (disk degeneration, Modic change, and spondylolisthesis) were evaluated. RESULTS: The aCSA ratio at C4 correlated with C2-C7 angle (r=0.267), C7 slope (r=0.207), T1 slope (r=0.221), disk degeneration at C3-4, C4-5, C5-6 (r=-0.234, -0.313, -0.262) and spondylolisthesis at C3 (anterior: r=-0.206, posterior: r=-0.249). The aCSA ratio at C7 correlated with disk degeneration at C3-4, C4-5, C5-6, C6-7 (r=-0.209, -0.294, -0.239, -0.209). The fat infiltration ratio at C4 correlated with TIA (r=0.306) and neck tilt (r=0.353), likewise the ratio at C7 correlated with TIA (r=0.270) and neck tilt (r=0.405). All correlations above were statistically significant with P<0.05. CONCLUSIONS: The paraspinal muscle volume showed significant relationship with the cervical balance parameters and disk degeneration. While, paraspinal muscle quality related to the thoracic inlet parameters. Our findings can be an important step to develop the knowledge of the association between cervical muscle and cervical degenerative disorders, as well as the sagittal balance of the cervical spine. LEVEL OF EVIDENCE: Level III.

Kinematic characteristics of patients with cervical imbalance: a weight-bearing dynamic MRI study.

STUDY DESIGN: It is a retrospective analysis of 1806 consecutive cervical magnetic resonance images taken in weight-bearing flexion, neutral, and extension positions. OBJECTIVE: The aim was to identify the kinematic characteristics of patients with cervical imbalance. Additionally, factors were analysed in the neutral position that could predict the characteristics. Little is known about the kinematic characteristics during cervical flexion and extension positions of the patient with cervical imbalance (cervical sagittal vertical axis (cSVA) in neutral position ≥ 40 mm). METHODS: After evaluating the whole images, cervical imbalance group (cSVA ≥ 40 mm, n = 43) and matched control group (< 40 mm, n = 43) were created using propensity score adjusting for age, gender, and cervical alignment. They were compared for cervical motion, changes in disc bulge, and ligamentum flavum (LF) bulge from flexion to extension. Multinomial logistic regression analysis and receiver operating characteristic curve analysis were calculated to verify the predictive factors and cut-off value of the identified characteristics. RESULTS: There were no significant differences in range of motion and the change in bulged discs. There was significant difference in the presence of LF bulge from flexion to extension (p = 0.023); the incidence of LF bulge increased sharply from neutral to extension in imbalance group, while there was linear increase in control group. The canal diameter (odds ratio = 0.61, p = 0.002) and disc height (odds ratio = 1.60, p = 0.041) showed significant relationship with the segments with LF bulge observed in extension but not in neutral position in the imbalance group; the cut-off values were 10.7 mm for canal diameter (sensitivity 82.5%, specificity 66.7%) and 7.1 mm for disc height (70.8%, 58.5%). CONCLUSION: Patients with cervical imbalance had a stark increase in LF bulge from the neutral to extension position. Canal diameter < 10.7 mm and disc height > 7.1 mm on neutral images may predict the segments with LF bulge observed in extension, but not in the neutral position. LEVEL OF EVIDENCE: II (Diagnostic: individual cross-sectional studies with consistently applied reference standard and blinding). These slides can be retrieved from Electronic Supplementary Material.

Small C7-T1 lordotic angle and muscle degeneration at C7 level were independent radiological characteristics of patients with cervical imbalance: a propensity score-matched analysis.

BACKGROUND CONTEXT: Cervical sagittal vertical axis (cSVA) of ≥40 mm is recognized as the key factor of poor health-related quality of life, poor surgical outcomes, and correction loss after surgery for cervical deformity. However, little is known about the radiological characteristics of patients with cSVA≥40 mm. PURPOSE: The purpose of this study was to identify the radiological characteristics of patients with cervical imbalance. DESIGN: Retrospective analysis of weight-bearing cervical magnetic resonance (MR) images. PATIENT SAMPLE: Consecutive 1,500 MR images of symptomatic patients in weight-bearing position. OUTCOME MEASURES: Cervical sagittal vertical axis, cervical alignment, cervical balance parameters (T1 slope, Co-C2 angle, C2-C7 angle, C7-T1 angle, neck tilt, and thoracic inlet angle), disc degeneration (Pfirmann and Suzuki classification), end plate degeneration (Modic change), spondylolisthesis (antero- and retrolisthesis), anteroposterior (AP) diameter of dural sac, cross-sectional area (CSA), and fat infiltration ratio of the transversospinalis muscles at C4 and C7 levels. METHODS: Patients were divided into two groups: cSVA≥40 mm and cSVA<40 mm. Gender, age, and cervical alignment were analyzed. Subsequently, matched imbalance (cSVA≥40 mm) and control (<40 mm) groups were created using the propensity score to adjust for age, gender, and cervical alignment. Cervicothoracic angular parameters, disc degeneration, Modic change, spondylolisthesis, and degeneration of the transversospinalis muscles at C4 and C7 were compared. Variables with p<.05 were included in the multinomial logistic regression model to identify factors that relate to the cervical balance grouping. RESULTS: The incidence of patients with cervical imbalance was 2.5% (37 patients). Those patients had a higher incidence of kyphosis, were older, and there were more male patients. In the matched imbalance group, the T1 slope was greater (p=.028), C7-T1 lordotic angle was smaller (p<.001), the number of anterolisthesis was greater (p=.012), and the fat infiltration ratio at C4 and C7 was higher (p=.023, 0.030) compared with the control. Logistic regression analysis showed that the C7-T1 angle (adjusted odds ratio [aOR]=0.592, p=.001) and fat infiltration ratio at C7 level (aOR=1.178, p=.030) were significant independent variables. CONCLUSIONS: Smaller C7-T1 lordotic angle and severe muscle degeneration at C7 level were independent characteristics of patients with cervical imbalance.

Trends analysis of surgical procedures for cervical degenerative disc disease and myelopathy in patients with tobacco use disorder.

PURPOSE: This study defined the incidence and trends of surgeries performed for patients with cervical disc degeneration with and without tobacco use disorder (TUD). METHODS: This study utilized the Humana Inc. database between 2007 and 2013 to identify patients with cervical disc degeneration with or without myelopathy. International Classification of Diseases, ninth revision (ICD-9) and Current Procedural Terminology (CPT) codes determined the initial diagnosis of disc degeneration, myelopathy status and TUD, whether patients received surgery, and TUD status at surgery. RESULTS: The prevalence of disc degeneration with myelopathy increased by 32.8% between 2007 and 2013, while disc disease with myelopathy and TUD increased by 91.6%. For patients without myelopathy, the prevalence of disc degeneration alone increased by 65.4%, and disc degeneration with myelopathy increased by 148.7%. Of myelopathy patients, 1717 (6.4%) had TUD and 1024 (59.6%) received surgery, compared to 6508 patients without TUD (26.1%). For patients without myelopathy, 11,337 (3.5%) had TUD and 787 (6.9%) underwent surgery, compared to 9716 patients (3%) without TUD. Of surgical patients, 781 (76.3%) with myelopathy and TUD still had a TUD diagnosis at surgery, and 542 (68.9%) of patients without myelopathy still had a TUD diagnosis at surgery. CONCLUSIONS: The prevalence of degenerative disc disease and TUD has increased more than disc disease alone. Patients with TUD were more likely to get surgery, and to have surgeries earlier than patients without TUD. Patients with TUD at the time of the diagnosis of their disc degeneration likely still had a TUD diagnosis at the time of surgery.

Duty cycling influences current generation in multi-anode environmental microbial fuel cells.

Improving microbial fuel cell (MFC) performance continues to be the subject of research, yet the role of operating conditions, specifically duty cycling, on MFC performance has been modestly addressed. We present a series of studies in which we use a 15-anode environmental MFC to explore how duty cycling (variations in the time an anode is connected) influences cumulative charge, current, and microbial composition. The data reveal particular switching intervals that result in the greatest time-normalized current. When disconnection times are sufficiently short, there is a striking decrease in current due to an increase in the overall electrode reaction resistance. This was observed over a number of whole cell potentials. Based on these results, we posit that replenishment of depleted electron donors within the biofilm and surrounding diffusion layer is necessary for maximum charge transfer, and that proton flux may be not limiting in the highly buffered aqueous phases that are common among environmental MFCs. Surprisingly, microbial diversity analyses found no discernible difference in gross community composition among duty cycling treatments, suggesting that duty cycling itself has little or no effect. Such duty cycling experiments are valuable in determining which factors govern performance of bioelectrochemical systems and might also be used to optimize field-deployed systems.