Isoflurane causes concentration-dependent inhibition of medullary raphé 5-HT neurons in situ

BACKGROUND

Anesthetics have a profound influence on a myriad of autonomic processes. Mechanisms of general anesthesia, and how these mechanisms give rise to the multifaceted state of anesthesia, are largely unknown. The ascending and descending serotonin (5-HT) networks are key modulators of autonomic pathways, and are critically involved in homeostatic reflexes across the motor, somatosensory, limbic and autonomic systems. These 5-HT networks are thought to contribute to anesthetic effects, but how anesthetics affect 5-HT neuron function remains a pertinent question. We hypothesized that the volatile anesthetic isoflurane inhibits action potential discharge of medullary raphé 5-HT neurons.

METHODS

We conducted extracellular recordings on individual neurons in the medullary raphé region of the unanesthetized in situ perfused brainstem preparation to determine how exposure to isoflurane affects 5-HT neurons. We examined changes in 5-HT neuron baseline firing in response to treatment with either 1, 1.5, or 2% isoflurane. We measured isoflurane concentrations by gas chromatography-mass spectrometry (GC-MS) analysis.

RESULTS

Exposure to isoflurane inhibited action potential discharge in raphé 5-HT neurons. We document a concentration-dependent inhibition over a range of concentrations approximating isoflurane MAC (minimum alveolar concentration required for surgical anesthesia). Delivered concentrations of isoflurane were confirmed using GC-MS analysis.

CONCLUSIONS

These findings illustrate that halogenated anesthetics greatly affect 5-HT neuron firing and suggest 5-HT neuron contributions to mechanisms of general anesthesia.

Traumatic spinal cord injury in the United States, 1993-2012

IMPORTANCE

Acute traumatic spinal cord injury results in disability and use of health care resources, yet data on contemporary national trends of traumatic spinal cord injury incidence and etiology are limited.

OBJECTIVE

To assess trends in acute traumatic spinal cord injury incidence, etiology, mortality, and associated surgical procedures in the United States from 1993 to 2012.

DESIGN, SETTING, AND PARTICIPANTS

Analysis of survey data from the US Nationwide Inpatient Sample databases for 1993-2012, including a total of 63,109 patients with acute traumatic spinal cord injury.

MAIN OUTCOMES AND MEASURES

Age- and sex-stratified incidence of acute traumatic spinal cord injury; trends in etiology and in-hospital mortality of acute traumatic spinal cord injury.

RESULTS

In 1993, the estimated incidence of acute spinal cord injury was 53 cases (95% CI, 52-54 cases) per 1 million persons based on 2659 actual cases. In 2012, the estimated incidence was 54 cases (95% CI, 53-55 cases) per 1 million population based on 3393 cases (average annual percentage change, 0.2%; 95% CI, -0.5% to 0.9%). Incidence rates among the younger male population declined from 1993 to 2012: for age 16 to 24 years, from 144 cases/million (2405 cases) to 87 cases/million (1770 cases) (average annual percentage change, -2.5%; 95% CI, -3.3% to -1.8%); for age 25 to 44 years, from 96 cases/million (3959 cases) to 71 cases/million persons (2930 cases), (average annual percentage change, -1.2%; 95% CI, -2.1% to -0.3%). A high rate of increase was observed in men aged 65 to 74 years (from 84 cases/million in 1993 [695 cases] to 131 cases/million [1465 cases]; average annual percentage change, 2.7%; 95% CI, 2.0%-3.5%). The percentage of spinal cord injury associated with falls increased significantly from 28% (95% CI, 26%-30%) in 1997-2000 to 66% (95% CI, 64%-68%) in 2010-2012 in those aged 65 years or older (P < .001). Although overall in-hospital mortality increased from 6.6% (95% CI, 6.1%-7.0%) in 1993-1996 to 7.5% (95% CI, 7.0%-8.0%) in 2010-2012 (P < .001), mortality decreased significantly from 24.2% (95% CI, 19.7%-28.7%) in 1993-1996 to 20.1% (95% CI, 17.0%-23.2%) in 2010-2012 (P = .003) among persons aged 85 years or older.

CONCLUSIONS AND RELEVANCE

Between 1993 and 2012, the incidence rate of acute traumatic spinal cord injury remained relatively stable but, reflecting an increasing population, the total number of cases increased. The largest increase in incidence was observed in older patients, largely associated with an increase in falls, and in-hospital mortality remained high, especially among elderly persons.

Validation of multisociety combined task force definitions of abnormal disk morphology

BACKGROUND AND PURPOSE

The multisociety task force descriptively defined abnormal lumbar disk morphology. We aimed to use their definitions to provide a higher level of evidence for the validation of MR imaging in the evaluation of this pathology in patients who have undergone diskectomy by retrospectively classifying their preoperative MRI.

MATERIALS AND METHODS

This retrospective, institutional review board-approved study included 54 of 86 consecutive patients (47 men; average age, 44 years) enrolled in an ongoing prospective trial of surgically treated lumbar disk herniation who had preoperative MRI and documented intraoperative classification of the abnormal disk as protrusion, extrusion, or sequestration by the treating surgeon. Preoperative MRI was classified by 2 blinded radiologists; discrepancies were resolved by a third reader. Statistical analysis of interobserver agreement and imaging compared with surgical findings was performed.

RESULTS

The readers disagreed on only 1 of the 54 cases. The third reader resolved the disagreement. Eight protrusions and 46 extrusions were found on imaging, with no sequestrations. At surgery, there were 13 protrusions and 40 extrusions, with 2 of the extrusions also containing sequestrations; the remaining case had only sequestration. There were 16 discrepancies between imaging and surgery, resulting in 70% agreement.

CONCLUSIONS

This study, which was intended to validate the multisociety combined task force definitions of abnormal disk morphology by using MR imaging with a surgical criterion standard, found 70% agreement between imaging diagnosis and surgical findings. Although reasonable, this finding highlights differences that often exist between intraoperative and preoperative imaging findings of lumbar disk herniation.

Survey finds few orthopedic surgeons know the costs of the devices they implant

Orthopedic procedures represent a large expense to the Medicare program, and costs of implantable medical devices account for a large proportion of those procedures' costs. Physicians have been encouraged to consider cost in the selection of devices, but several factors make acquiring cost information difficult. To assess physicians' levels of knowledge about costs, we asked orthopedic attending physicians and residents at seven academic medical centers to estimate the costs of thirteen commonly used orthopedic devices between December 2012 and March 2013. The actual cost of each device was determined at each institution; estimates within 20 percent of the actual cost were considered correct. Among the 503 physicians who completed our survey, attending physicians correctly estimated the cost of the device 21 percent of the time, and residents did so 17 percent of the time. Thirty-six percent of physicians and 75 percent of residents rated their knowledge of device costs "below average" or "poor." However, more than 80 percent of all respondents indicated that cost should be "moderately," "very," or "extremely" important in the device selection process. Surgeons need increased access to information on the relative prices of devices and should be incentivized to participate in cost containment efforts.

Comparison of locked plate fixation and nonoperative management for displaced proximal humerus fractures in elderly patients

Use of locked plate fixation for proximal humerus fractures in elderly patients has increased markedly in recent years. We conducted a study to compare outcomes of operative (locked plate fixation) and nonoperative management of these fractures. From our database, we identified 207 displaced proximal humerus fractures that met all inclusion and exclusion criteria. For patients who accepted our invitation to return for evaluation, clinical outcome was assessed using several questionnaires: Constant; DASH (Disabilities of the Arm, Shoulder, and Hand); SMFA (Short Musculoskeletal Functional Assessment); and Patient Reported Outcomes Measurement Information System (PROMIS) Physical Function Computer Adaptive Test. Of the 207 patients, 61 were managed operatively and 146 nonoperatively. Operative patients had lower rates of malunion but higher rates of complications, which included screw perforation, loss of fixation, infection, and secondary surgical procedures. Forty-seven patients (a mix of operative and nonoperative) accepted our invitation to return for clinical evaluation at a mean follow-up of 3.3 years. The 2 groups' clinical outcomes were similar.

Operative compared with nonoperative treatment of a thoracolumbar burst fracture without neurological deficit: a prospective randomized study with follow-up at sixteen to twenty-two years

BACKGROUND

Studies comparing operative with nonoperative treatment of a stable burst fracture of the thoracolumbar junction in neurologically intact patients have not shown a meaningful difference at early follow-up. To our knowledge, longer-term outcome data have not before been presented.

METHODS

From 1992 to 1998, forty-seven consecutive patients with a stable thoracolumbar burst fracture and no neurological deficit were evaluated and randomized to one of two treatment groups: operative treatment (posterior or anterior arthrodesis) or nonoperative treatment (a body cast or orthosis). We previously reported the results of follow-up at an average of forty-four months. The current study presents the results of long-term follow-up, at an average of eighteen years (range, sixteen to twenty-two years). As in the earlier study, patients at long-term follow-up indicated the degree of pain on a visual analog scale and completed the Roland and Morris disability questionnaire, the Oswestry Disability Index (ODI) questionnaire, and the Short Form-36 (SF-36) health survey. Work and health status were obtained, and patients were evaluated radiographically.

RESULTS

Of the original operatively treated group of twenty-four patients, follow-up data were obtained for nineteen; one patient had died, and four could not be located. Of the original nonoperatively treated group of twenty-three patients, data were obtained for eighteen; two patients had died, and three could not be located. The average kyphosis was not significantly different between the two groups (13° for those who received operative treatment compared with 19° for those treated nonoperatively). Median scores for pain (4 cm for the operative group and 1.5 cm for the nonoperative group; p = 0.003), ODI scores (20 for the operative group and 2 for the nonoperative group; p <0.001) and Roland and Morris scores (7 for the operative group and 1 for the nonoperative group; p = 0.001) were all significantly better in the group treated nonoperatively. Seven of eight SF-36 scores also favored nonoperative treatment.

CONCLUSIONS

While early analysis (four years) revealed few significant differences between the two groups, at long-term follow-up (sixteen to twenty-two years), those with a stable burst fracture who were treated nonoperatively reported less pain and better function compared with those who were treated surgically.

Predicting patients with concurrent noncontiguous spinal epidural abscess lesions

BACKGROUND CONTEXT

Spinal epidural abscess (SEA) is a serious condition that can lead to significant morbidity and mortality if not expeditiously diagnosed and appropriately treated. However, the nonspecific findings that accompany SEAs often make its diagnosis difficult. Concurrent noncontiguous SEAs are even more challenging to diagnose because whole-spine imaging is not routinely performed unless the patient demonstrates neurologic findings that are inconsistent with the identified lesion. Failure to recognize a separate SEA can subject patients to a second operation, continued sepsis, paralysis, or even death.

PURPOSE

To formulate a set of clinical and laboratory predictors for identifying patients with concurrent noncontiguous SEAs.

STUDY DESIGN

A retrospective, case-control study.

PATIENT SAMPLE

Patients aged 18 years or older admitted to our institution during the study period who underwent entire spinal imaging and were diagnosed with one or more SEAs.

OUTCOME MEASURES

The presence or absence of concurrent noncontiguous SEAs on magnetic resonance imaging or computed tomography (CT)-myelogram.

METHODS

A retrospective review was performed on 233 adults with SEAs who presented to our health-care system from 1993 to 2011 and underwent entire spinal imaging. The clinical and radiographic features of patients with concurrent noncontiguous SEAs, defined as at least two lesions in different anatomical regions of the spine (ie, cervical, thoracic, or lumbar), were compared with those with a single SEA. Multivariate logistic regression identified independent predictors for the presence of a skip SEA, and a prediction algorithm based on these independent predictors was constructed. Institutional review board committee approval was obtained before initiating the study.

RESULTS

Univariate and multivariate analyses comparing patients with skip SEA lesions (n=22) with those with single lesions (n=211) demonstrated significant differences in three factors: delay in presentation (defined as symptoms for ≥7 days), a concomitant area of infection outside the spine and paraspinal region, and an erythrocyte sedimentation rate of >95 mm/h at presentation. The predicted probability for the presence of a skip lesion was 73% for patients possessing all three predictors, 13% for two, 2% for one, and 0% for zero predictors. Receiver operating characteristic curve analysis, used to evaluate the predictive accuracy of the model, revealed a steep shoulder with an area under the curve of 0.936 (p<.001).

CONCLUSIONS

The proposed set of three predictors may be a useful tool in predicting the risk of a skip SEA lesion and, consequently, which patients would benefit from entire spinal imaging.

Variations in Medicare payments for episodes of spine surgery

BACKGROUND CONTEXT

Although the high cost of spine surgery is generally recognized, there is little information on the extent to which payments vary across hospitals.

PURPOSE

To examine the variation in episode payments for spine surgery in the national Medicare population. We also sought to determine the root causes for observed variations in payment at high cost hospitals.

STUDY DESIGN

All patients in the national fee for service Medicare population undergoing surgery for three conditions (spinal stenosis, spondylolisthesis, and lumbar disc herniation) between 2005 and 2007 were included.

PATIENT SAMPLE

Included 185,954 episodes of spine surgery performed between 2005 and 2007.

OUTCOME MEASURES

Payments per episode of spine surgery.

METHODS

All patients in the national fee for service Medicare population undergoing surgery for three conditions (spinal stenosis, spondylolisthesis, and lumbar disc herniation) between 2005 and 2007 were identified (n=185,954 episodes of spine surgery). Hospitals were ranked on least to most expensive and grouped into quintiles. Results were risk- and price-adjusted using the empirical Bayes method. We then assessed the contributions of index hospitalization, physician services, readmissions, and postacute care to the overall variations in payment.

RESULTS

Episode payments for hospitals in the highest quintile were more than twice as high as those made to hospitals in the lowest quintile ($34,171 vs. $15,997). After risk- and price-adjustment, total episode payments to hospitals in the highest quintile remained $9,210 (47%) higher. Procedure choice, including the use of fusion, was a major determinant of the total episode payment. After adjusting for procedure choice, however, hospitals in the highest quintile continued to be 28% more expensive than those in the lowest. Differences in the use of postacute care accounted for most of this residual variation in payments across hospitals. Hospital episode payments varied to a similar degree after subgroup analyses for disc herniation, spinal stenosis, and spondylolisthesis. Hospitals expensive for one condition were also found to be expensive for services provided for other spinal diagnoses.

CONCLUSIONS

Medicare payments for episodes of spine surgery vary widely across hospitals. As they respond to the new financial incentives inherent in health care reform, high cost hospitals should focus on the use of spinal fusion and postacute care.

The effect of the Massachusetts healthcare reform on the uninsured rate of the orthopaedic trauma population

BACKGROUND

The 2006 Massachusetts Healthcare Reform (MHR) has resulted in health coverage for 98.1% of residents in Massachusetts. The purpose of this study was to evaluate the effect of MHR on the actual rate of uninsured individuals in the orthopaedic trauma population in the largest metropolitan area of Massachusetts. We also sought to measure the change in uncompensated care following the implementation of MHR.

METHODS

We performed a retrospective review of all patients treated by the orthopaedic trauma services at three of the four level-I trauma centers in Boston from 2003 to 2010. The primary study cohort consisted of all uninsured patients, while the remaining patients were considered to have insurance. The study population was divided into two groups to compare the uninsured rate before and after MHR. Patients from 2006 to 2007 were excluded from the analysis to allow for an enrollment period in subsidized health insurance.

RESULTS

A total of 16,338 patients with extremity and pelvic fractures and dislocations were treated from 2003 to 2010. There was a significant decrease in the uninsured rate from 23.8% to 14.4% following MHR (p < 0.001). The post-MHR risk of being uninsured is approximately 0.6 times the pre-MHR risk, with a 95% confidence interval of 0.56 to 0.65. There was also a reduction in the proportion of uncompensated care from 16.7% to 11.5% after MHR.

CONCLUSIONS

There was an estimated 40% reduction in risk of uninsured individuals in the orthopaedic trauma population in the metropolitan Boston area following MHR. Despite a significant improvement, these results reveal a rate of uninsured individuals fivefold greater than currently reported by the state of Massachusetts and the U.S. government.

Independent predictors of failure of nonoperative management of spinal epidural abscesses

BACKGROUND CONTEXT

The notion that all patients with spinal epidural abscess (SEA) require surgical decompression has been recently challenged by reports of successful medical management of select patients with SEA.

PURPOSE

The purpose of this study was to identify the independent variables that determine success or failure of medical management of SEA.

STUDY DESIGN/SETTING

This was a retrospective, case-control study.

PATIENT SAMPLE

Patients 18 years or older with diagnosis of SEA admitted to our institution during the study period were included in the sample.

OUTCOME MEASURES

The outcome measure was successful management of SEA by eradication of the infection without worsening of neurologic deficits.

METHODS

All patients admitted to our health-care system with a diagnosis of SEA from 1993 to 2011 were identified and the data were retrospectively collected. Patients 18 years or older diagnosed with SEA were included. Excluded were those with postsurgical SEA or phlegmon without an abscess and those with a complete spinal cord injury from SEA for longer than 48 hours.

RESULTS

A total of 355 patients with average age of 60 years met our inclusion criteria. Of the patients who initially underwent nonoperative treatment, 54 patients failed medical management and 73 patients were successfully treated without surgery. Univariate and multivariate analysis identified incomplete or complete spinal cord deficits as the most significant risk factor for failure of medical management. Age older than 65 years, diabetes, and methicillin-resistant Staphylococcus aureus (MRSA) were also independent risk factors for failure. An algorithm for probability of failed antibiotic management of spinal epidural abscess predicted 99% probability of failure for patients with all four of these risk factors.

CONCLUSIONS

SEA treated with medical management alone has a very high risk for failure if the patient is older than 65 years with diabetes, MRSA infection, or neurologic compromise. In the absence of these risk factors, nonoperative management of spinal epidural abscess may be considered as the initial line of treatment with close monitoring.

Traumatic thoracolumbar spine injuries: what the spine surgeon wants to know

The Thoracolumbar Injury Classification and Severity Score (TLICS) is a scoring and classification system developed by the Spine Trauma Study Group in response to the recognition that previous classification systems have limited prognostic value and generally do not suggest treatment pathways. The TLICS provides a spine injury severity score based on three components: injury morphology, integrity of the posterior ligamentous complex (PLC), and neurologic status of the patient. A numerical score is calculated for each category, with a lower point value assigned to a less severe or less urgent injury and a higher point value assigned to a more severe injury requiring urgent management. The total score helps guide decision making about surgical versus nonsurgical management. The TLICS also emphasizes the importance of magnetic resonance imaging in evaluating PLC injury and acknowledges that the primary driver of surgical intervention is the patient's neurologic status. Knowledge of PLC anatomy and its significance is essential in recognizing unstable injuries. Signs of PLC injury at computed tomography include interspinous distance widening, facet joint widening, spinous process fracture, and vertebral subluxation or dislocation. Familiarity with the TLICS will help radiologists who interpret spine trauma imaging studies to effectively communicate findings to spine trauma surgeons. The complete article is available online .

Prevalence and risk factors for periprosthetic fracture in older recipients of total hip replacement: a cohort study

Background

The growing utilization of total joint replacement will increase the frequency of its complications, including periprosthetic fracture. The prevalence and risk factors of periprosthetic fracture require further study, particularly over the course of long-term follow-up. The objective of this study was to estimate the prevalence and risk factors for periprosthetic fractures occurring in recipients of total hip replacement.

Methods

We identified Medicare beneficiaries who had elective primary total hip replacement (THR) for non-fracture diagnoses between July 1995 and June 1996. We followed them using Medicare Part A claims data through 2008. We used ICD-9 codes to identify periprosthetic femoral fractures occurring from 2006–2008. We used the incidence density method to calculate the annual incidence of these fractures and Cox proportional hazards models to identify risk factors for periprosthetic fracture. We also calculated the risk of hospitalization over the subsequent year.

Results

Of 58,521 Medicare beneficiaries who had elective primary THR between July 1995 and June 1996, 32,463 (55%) survived until January 2006. Of these, 215 (0.7%) developed a periprosthetic femoral fracture between 2006 and 2008. The annual incidence of periprosthetic fracture among these individuals was 26 per 10,000 person-years. In the Cox model, a greater risk of periprosthetic fracture was associated with having had a total knee replacement (HR 1.82, 95% CI 1.30, 2.55) or a revision total hip replacement (HR1.40, 95% CI 0.95, 2.07) between the primary THR and 2006. Compared to those without fractures, THR recipients who sustained periprosthetic femoral fracture had three-fold higher risk of hospitalization in the subsequent year (89% vs. 27%, p < 0.0001).

Conclusion

A decade after primary THR, periprosthetic fractures occur annually in 26 per 10,000 persons and are especially frequent in those with prior total knee or revision total hip replacements.

A group of non-serotonergic cells is CO2-stimulated in the medullary raphé

Serotonin/substance P synthesizing cells in the raphé nuclei of the brain are candidates for designation as central chemoreceptors that are stimulated by CO2/pH. We have previously demonstrated that these neurons are CO2-stimulated in situ. Evidence also suggests that CO2-inhibited raphé neurons recorded in vitro and in situ synthesize GABA. Unknown is whether there are other types of chemosensitive cells in the raphé. Here, we showed that a previously unrecognized pool of raphé neurons also exhibit chemosensitivity, and that they are not serotonergic. We used extracellular recording of individual raphé neurons in the unanesthetized juvenile rat in situ perfused decerebrate brainstem preparation to assess chemosensitivity of raphé neurons. Subsequent juxtacellular labeling of individually recorded cells, and immunohistochemistry for the serotonin synthesizing enzyme tryptophan hydroxylase and for neurokinin-1 receptor (NK1R; the receptor for substance P) indicated a group of CO2-stimulated cells that are not serotonergic, but express NK1R and are closely apposed to surrounding serotonergic cells. CO2-stimulated 5-HT and non-5-HT cells constitute distinct groups that have different firing characteristics and hypercapnic sensitivities. Non-5-HT cells fire faster and are more robustly stimulated by CO2 than are 5-HT cells. Thus, we have characterized a previously unrecognized type of CO2-stimulated medullary raphé neuron that is not serotonergic, but may receive input from neighboring serotonin/substance P synthesizing chemosensitive neurons. The potential network properties of the three types of chemosensitive raphé neurons (the present non-5-HT cells, serotonergic cells, and CO2-inhibited cells) remain to be elucidated.

Closing the loop between evidence-based medicine and care delivery: a possible role for clinical audits in spinal surgery

BACKGROUND CONTEXT

Evidence-based medicine (EBM) should be the ultimate force driving change in clinical practice. This process generally occurs through a trickle-down phenomenon by which practice recommendations are revised, modified, and/or changed based on the best published data. Recommendations are subsequently incorporated by individual physicians. The fundamental assumption that drives this paradigm is that adopting evidence-based recommendations and/or treatment guidelines will result in improved outcomes. Unfortunately, to date, the paradigm does not have an effective feedback loop that would then evaluate whether the changes did, in fact, improve outcomes.

PURPOSE

To explore the process of clinical audits as a mechanism by which to provide a feedback loop to evaluate the results of spinal surgery on an individual basis and whether those results can be improved.

STUDY DESIGN

Review article, discussion.

METHODS

A literature review of the current data regarding clinical audits was performed, and a discussion of how they may apply to spinal surgery is offered.

RESULTS

Clinical audits have been used outside the United States, particularly in the United Kingdom, to fulfill this function. A clinical audit would allow a practicing spinal surgeon to examine his or her individual experience and determine if it is achieving the expected outcome based on published results. In the most important feature of a clinical audit, the reaudit, if an individual's results are found to be inconsistent with published results, it presents an opportunity to identify if there are reconcilable differences from which potential improvements can be made. Effectively, this "closes the loop" between EBM and actual clinical practice.

CONCLUSIONS

Documenting improved outcomes through the audit process can impact spinal care in several ways. Patients would receive a clear message that their doctors are interested in improving care. Hospitals will use the information to optimize treatment algorithms. Finally, insurers might make the audit process more tenable or attractive by indicating a physician's voluntary participation as a criterion to be a preferred provider.

Factors associated with the decision for operative versus non-operative treatment of displaced proximal humerus fractures in the elderly

BACKGROUND

In the management of displaced proximal humerus fractures in the elderly, wide variation has been documented. However, no prior study has investigated the factors that currently lead surgeons to treat patients with surgical fixation, arthroplasty or non-operative management. The purpose of this study was to identify the factors associated with treatment selection in the management of displaced proximal humerus fractures in individuals over the age of 60 years. To this end, we conducted a retrospective review of all such injuries that presented to our two level-I trauma centres between 2006 and 2009.

PATIENTS AND METHODS

From our prospectively collected trauma database, we identified 229 displaced proximal humerus fractures that met all inclusion and exclusion criteria. Data were collected on patient-, fracture- and surgeon-related characteristics that were plausibly related to the decision for treatment. The choice of management was recorded, and logistic regression was used to identify factors associated with the decision for treatment.

RESULTS

In the multivariate analysis, the predictors of operative intervention as opposed to non-operative treatment were younger patient age (p = 0.038), associated orthopaedic injuries requiring surgery (p = 0.012), higher Arbeitsgemeinschaft für Osteosynthesefragen (AO) classification (p = 0.012), translation-type displacement (p = 0.0012) and associated glenohumeral dislocation (p = 0.0006). In addition, shoulder and upper extremity specialists were found to choose operative intervention significantly more frequently than orthopaedic trauma specialists (49.1% vs. 26.1%, adjusted relative risk (RR) 1.96, p = 0.012). Factors associated with the decision for arthroplasty as opposed to fixation were higher Charlson score (p = 0.045), higher Neer classification (p = 0.012), and higher AO classification (p = 0.0097).

CONCLUSIONS

In this study of displaced proximal humerus fractures in the elderly, the decision for surgery was influenced by the patient's age, the presence of associated orthopaedic injuries, the severity of the fracture and the presence of an associated glenohumeral dislocation. In addition, treatment by a shoulder or upper extremity specialist (as opposed to an orthopaedic trauma specialist) was associated with a higher likelihood of operative intervention. Further investigation into the resultant clinical outcomes is required to determine whether the use of these characteristics to select operative candidates is appropriate and beneficial for patients.

Cardiovascular disease risk following a 758 km pilgrimage

Millions of people participate in pilgrimages around the world such as the Camino de Santiago. However, few studies have examined the effects of this type of activity on cardiovascular disease risk factors. The aim of this study is to evaluate changes in cardiovascular disease risk factors: c-reactive protein, cholesterol, triglycerides, blood pressure, and cardiorespiratory fitness levels following a 758 km, 30-day pilgrimage. 11 healthy male and female subjects between the ages of 18-56 participated in pre and post pilgrimage blood pressure and blood tests, as well as pre, during, and post pilgrimage weight, skin-fold, and aerobic fitness testing. Heart rate monitors and pedometers provided maximum, average, and minimum heart rates as well as distances covered during the exercise. The mean daily walking distance was 25 km at an average intensity of 55.96% (±1.93%) of maximum heart rate. Statistically significant changes were seen in body weight (79.3 kg±3.4 pre vs. 76.4±2.98 post, p<0.05), body fat percentage (24.48%±2.31% pre vs. 23.01%±2.12 post, p<0.05), systolic and diastolic blood pressure (119±3.82/75±2.73 pre vs. 110±5.07/69±3.10 post, p<0.05), as well as cardiorespiratory fitness. These data suggest that some cardiovascular disease risk factors can be improved in healthy subjects participating in a low intensity, long duration, high frequency activity such as a walking pilgrimage.

The role of preoperative transarterial embolization in spinal tumors. A large single-center experience

BACKGROUND CONTEXT

Patients with spinal tumors are often referred for preoperative angiography and embolization before surgical resection to minimize intraoperative bleeding.

PURPOSE

The purpose of the present study was to investigate the angiographic appearance of a variety of spinal tumors, assess the safety and efficacy of preoperative embolization in relation to the amount of intraoperative blood loss, and correlate intraoperative tumor histology with the degree of gadolinium enhancement on spinal magnetic resonance imaging (MRI) and tumor vascularity visualized during angiography.

STUDY DESIGN/SETTING

Retrospective and single-institution cohort study.

PATIENT SAMPLE

One hundred four patients with spinal tumors referred for preoperative embolization.

OUTCOME MEASURES

Effectiveness of preoperative embolization in relation to intraoperative blood loss and number of transfused packed red blood cell units in perioperative period (72 hours).

METHODS

From 2000 to 2009, 104 patients with spinal tumors underwent 114 spinal angiographies with the intent to embolize feeder vessels before surgery. The effectiveness of embolization was compared with the documented intraoperative blood loss. Angiographic tumor vascularity was graded from 0 (avascular) to 3 (highly vascular). Ninety-four patients had a pre- and post-gadolinium-enhanced MRI of the spine before transarterial embolization. Magnetic resonance imaging vascular enhancement was classified as Grade 3 (avid contrast enhancement), Grade 2 (moderate), or Grade 1 (mild).

RESULTS

Transarterial tumor embolization was angiographically complete in 63 (66%) and partial in 33 procedures (34%). In 18 cases, the target was not deemed suitable for embolization. A limited statistical analysis did not reveal a statistical difference in documented intraoperative blood loss between patients with complete versus partial embolization for the entire cohort or when stratified into renal cell carcinoma (RCC; p=.64), multiple myeloma (p=.28), malignant (p=.17) and benign tumor groups (p=.26). There were no clinical complications associated with embolization. There was poor correlation between MRI enhancement and angiographic vascularity.

CONCLUSIONS

Preoperative embolization was angiographically effective in most cases. Avid gadolinium enhancement (Grade 3) on MRI was not predictive of hypervascularity on angiography. Furthermore, hypervascularity was not restricted to classically vascular tumors, such as RCC, as it was noted in some patients with breast and prostate cancer. However, with the available numbers, the quality of preoperative embolization did not significantly affect intraoperative blood loss. A future prospective randomized controlled study may be warranted to better characterize the benefits of preoperative embolization for spinal tumors.

Epidemiology of cervical spine fractures in the US military

BACKGROUND CONTEXT

The epidemiology of cervical spine fractures and associated spinal cord injury (SCI) has not previously been estimated within the American population.

PURPOSE

To determine the incidence of cervical spine fractures and associated SCI and identify potential risk factors for these injuries in a large multicultural military population.

STUDY DESIGN

Query of a prospectively collected military database.

PATIENT SAMPLE

The 13,813,333 military servicemembers serving in the US Armed Forces between 2000 and 2009.

OUTCOME MEASURES

The Defense Medical Epidemiology Database (DMED) was queried to identify all servicemembers diagnosed with cervical spine fractures with and without SCI during the time period under investigation. Data were used to determine the incidence of cervical spine fractures and SCI as well as identify risk factors for their development.

METHODS

The DMED was queried for the years 2000 to 2009 using the International Classification of Diseases, Ninth Revision, Clinical Modification code for cervical spine fractures with and without SCI (805.0, 805.1, 806.0, and 806.1). The database was also used to determine the total number of servicemembers within the military during the same period. The incidence of cervical spine fractures and fractures associated with SCI was determined, and unadjusted incidence rates were calculated for the demographic characteristics of sex, race, military rank, branch of service, and age. Adjusted incidence rate ratios were then determined using multivariate Poisson regression analysis to control for other factors in the model and identify significant risk factors for cervical spine fractures and cervical injuries associated with SCI.

RESULTS

From 2000 to 2009, there were 4,048 cervical spine fractures in a population at risk of 13,813,333 servicemembers. The overall incidence of cervical spine fractures was 0.29 per 1,000 person-years, and the incidence of fracture associated SCI was 70 per 1,000,000. The cohorts at highest risk of cervical spine fracture were males, whites, Enlisted personnel, those serving in the Army, Navy, or Marine Corps, and servicemembers aged 20 to 29. Risk of fracture-associated SCI was significantly increased in males, Enlisted personnel, servicemembers in the Army, Navy, or Marines, and those aged 20 to 29.

CONCLUSIONS

This study is the largest population-based investigation to be conducted within the United States regarding the incidence of SCI and the only study addressing incidence and risk factors for cervical spine fractures. Male sex, white race, Enlisted military rank, service in the Army, Navy, or Marine Corps, and ages 20 to 29 were found to significantly increase the risk for cervical fractures and/or fracture associated SCI. Our findings support previously published data but also represent best available evidence based on the size and diversity of the population under study.

LEVEL OF EVIDENCE

Prognostic; Level II.

Fracture pattern and fixation type related to loss of reduction in bicondylar tibial plateau fractures

INTRODUCTION

Bicondylar tibial plateau fractures can be treated with locked plating applied from the lateral side with or without additional application of a medial plate (dual plating). Recent studies demonstrate that these injuries can be sub-grouped based upon their morphology by computed tomography (CT). The purpose of this study is to evaluate the relationship between fracture pattern, method of fixation and loss of reduction in bicondylar tibial plateau fractures.

PATIENTS AND METHODS

Preoperative CT scans and postoperative plain films were evaluated on a consecutive series of bicondylar tibial plateau fractures. Fracture patterns were classified by CT. Angular alignment was measured immediately postoperatively and again at clinical and radiographic union to assess loss of reduction.

RESULTS

A total of 140 patients were studied. Sixty-six (47%) had a single large medial fragment with the articular surface intact, 19 (14%) had a medial articular fracture line with a mainly sagittal component and 55 (39%) had a coronal fracture through the medial articular surface. A total of 129 patients had been treated with lateral locked plating alone whilst 11 patients (all with a coronal fracture of the medial condyle) underwent dual plating. There was little loss of reduction (median subsidence 0.5°) when lateral locked plating was employed alone in patients with a single medial fracture fragment or with a sagittal medial fracture line. When lateral locked plating was used in the presence of a medial coronal fracture line, there was a significantly higher rate of subsidence (median 2.0°) compared to those with no medial fracture line (p=0.002). Patients with coronal fracture lines treated with dual plating had significantly less loss of reduction that those treated with lateral locked plating (p=0.01).

CONCLUSIONS

Most patients with bicondylar tibial plateau fractures do well when treated with lateral locked plating. However, those with a medial coronal fracture line tend to have a higher rate of subsidence and loss of reduction when lateral locked plating is employed alone. These fractures may be better treated with dual plating if the soft tissues allow.

LEVEL OF EVIDENCE

Level III (retrospective comparative study).

Risk factors for cervical spine injury

INTRODUCTION

The early recognition of cervical spine injury remains a top priority of acute trauma care. Missed diagnoses can lead to exacerbation of an existing injury and potentially devastating consequences. We sought to identify predictors of cervical spine injury.

METHODS

Trauma registry records for blunt trauma patients cared for at a Level I Trauma Centre from 1997 to 2002 were examined. Cervical spine injury included all cervical dislocations, fractures, fractures with spinal cord injury, and isolated spinal cord injuries. Univariate and adjusted odds ratios (ORs) were calculated to identify potential risk factors. Variables and two-way interaction terms were subjected to multivariate analysis using backward conditional stepwise logistic regression.

RESULTS

Data from 18,644 patients, with 55,609 injuries, were examined. A total of 1255 individuals (6.7%) had cervical spine injuries. Motor Vehicle Collision (MVC) (odds ratio (OR) of 1.61 (1.26, 2.06)), fall (OR of 2.14 (1.63, 2.79)), age <40 (OR of 1.75 (1.38-2.17)), pelvic fracture (OR of 9.18 (6.96, 12.11)), Injury Severity Score (ISS) >15 (OR of 7.55 (6.16-9.25)), were all significant individual predictors of cervical spine injury. Neither facial fracture nor head injury alone were associated with an increased risk of cervical spine injury. Significant interactions between pelvic fracture and fall and pelvic fracture and head injury were associated with a markedly increased risk of cervical spine (OR 19.6 (13.1, 28.8)) and (OR 27.2 (10.0-51.3)).

CONCLUSIONS

MVC and falls were independently associated with cervical spine injury. Pelvic fracture and fall and pelvic fracture and head injury, had a greater than multiplicative interaction and high risk for cervical spine injury, warranting increased vigilance in the evaluation of patients with this combination of injuries.