Mark L. Prasarn

Conflict of Interest in Orthopaedic Research

BACKGROUND The expanding role of industrial support in biomedical research has resulted in both substantial interest and controversy in recent years. Our hypothesis was that, from 1985 to 2002, the role of industrial support in orthopaedic research increased, as documented by the research presented at the annual meetings of the American Academy of Orthopaedic Surgeons. METHODS We analyzed the frequency and types of self-reported conflicts of interest for all presentations at the annual meetings of the American Academy of Orthopaedic Surgeons in 1985, 1988, 1992, 1997, 1999, and 2002. Conflicts of interest were recorded directly from the final program for each meeting analyzed. The analysis focused on the scientific presentations, Instructional Course Lectures, symposia, poster exhibits, and scientific exhibits. Information about specific types of support received by authors was first required in 1988. RESULTS The incidence of conflicts of interest increased from 3% in 1985 to 39% in 2002 for scientific papers (p < 0.001); from 10% to 74%, respectively, for symposia (p < 0.001); from 22% to 60% for Instructional Course Lectures (p < 0.001); from 10% to 60% for scientific exhibits (p < 0.001); and from 9% in 1992 to 14% in 2002 for posters (p < 0.001). For presentations of all types, the incidence increased from 10% to 32% (p < 0.001). The types of conflict of interest also changed significantly from 1999 to 2002. In 1999, 73% of conflicts were documented as support directed to institutions and 27%, as support to individuals; in 2002, 57% were reported as support directed to institutions and 43%, as support to individuals (p < 0.01). CONCLUSIONS The role of industrial support of orthopaedic research increased significantly between 1985 and 2002, as evidenced by the increase in the self-reported conflicts of interest for all types of presentations at the annual meetings of the American Academy of Orthopaedic Surgeons. In addition, the support directed to individuals, in contrast to that directed to institutions, increased significantly.

Acute compartment syndrome of the upper extremity.

&NA; Acute compartment syndrome occurs when pressure within a fibroosseous space increases to a level that results in a decreased perfusion gradient across tissue capillary beds. Compartment syndromes of the hand, forearm, and upper arm can result in tissue necrosis, which can lead to devastating loss of function. The etiology of acute compartment syndrome in the upper extremity is diverse, and a high index of suspicion must be maintained. Pain out of proportion to injury is the most reliable early symptom of impending compartment syndrome. Diagnosis is particularly difficult in obtunded patients and in young children. Early recognition and expeditious surgical treatment are essential to obtain a good clinical outcome and prevent permanent disability.

Dual Plating for Fractures of the Distal Third of the Humeral Shaft

In this study, we present a novel method for performing dual plating of extra-articular fractures of the distal third of the humerus. Since 2006, we have treated 15 such fractures with dual plates from a single posterior midline incision. In the first part of the study, we provide the surgical protocol we have used in addressing these fractures. In the second part, the charts of these patients were reviewed retrospectively to examine their clinical and radiographic outcomes. Using this technique, we have achieved an excellent union rate without significant complications while allowing early and aggressive range of motion.

Arterial anatomy of the talus: a cadaver and gadolinium-enhanced MRI study.

Background: Avascular necrosis following a fracture of the talar neck may be secondary to the injury itself, or may result from the surgical approach and exposure during treatment. We sought to define the arterial anatomy of the talus using gadolinium-enhanced magnetic resonance imaging (MRI) and through gross dissection following latex injection of cadaver limbs. The use of gadolinium-enhanced MRI for the evaluation of the arterial supply of the talus has not been previously reported. Methods and Materials: We utilized 12 fresh frozen cadaver limbs to study the arterial anatomy of the talus. The anterior tibial, posterior tibial, and peroneal arteries were isolated and cannulated with polyethylene catheters. Gadolinium was injected into the cannulas, and conventional MRI sequences including suppressed and unsuppressed 3D gradient echo sequences obtained. Following MRI, latex was injected into the cannulas and gross dissection performed. In addition, the vascular constraints to anteromedial and anterolateral approaches to the talus were defined. Results: MRI proved useful in the present study to confirm the presence of specific arterial branches in situ, as well as to demonstrate the rich anastomotic network in and around the talus. A branch to the medial talar neck that has not been previously identified is described which was found in nine of the specimens. This newly described branch to the medial talar neck was consistently noted to be lacerated following a standard anteromedial approach to the talus. Conclusion: The use of gadolinium-enhanced MRI provided very detailed images demonstrating a rich and complex anastomotic arterial network that surrounds and perforates the talus. Clinical Relevance: A thorough understanding of the anatomy and meticulous dissection are essential to prevent unnecessary further injury to the vasculature when treating fractures of the talus.

Smoking Cessation Related to Improved Patient-Reported Pain Scores Following Spinal Care.

BACKGROUND Smoking is associated with low back pain, intervertebral disc disease, inferior patient outcomes following surgical interventions, and increased rates of postoperative complications. The purpose of the present study was to examine the effect of smoking and smoking cessation on pain and disability in patients with painful spinal disorders. METHODS We examined a prospectively maintained database of records for 5333 patients with axial or radicular pain from a spinal disorder with regard to smoking history and the patient assessment of pain on four visual analog scales during the course of care. Confounding factors, including secondary gain, sex, age, and body mass index, were also examined. The mean duration of follow-up was eight months. Multivariate statistical analysis was performed with variables including smoking status, secondary gain status, sex, depression, and age as predictors of pain and disability. RESULTS Compared with patients who had never smoked, patients who were current smokers reported significantly greater pain in all visual analog scale pain ratings (p < 0.001). The mean improvement in reported pain over the course of care was significantly different between nonsmokers and current smokers (p <0.001). Compared with patients who had continued to smoke, those who had quit smoking during the course of care reported significantly greater improvement in pain in visual analog scale pain ratings for worst (p = 0.013), current (p < 0.05), and average weekly pain (p = 0.024). The mean improvement in the visual analog scale pain ratings was clinically important in patients in all three groups of nonsmokers. As a group, those who had continued smoking during treatment had no clinically important improvement in reported pain. CONCLUSIONS Given a strong association between improved patient-reported pain and smoking cessation, this study supports the need for smoking cessation programs for patients with a painful spinal disorder.

Quantitative Assessment of the Vascularity of the Talus with Gadolinium-enhanced Magnetic Resonance Imaging

BACKGROUND The purpose of this study was to quantify the various arterial contributions to the talus with use of magnetic resonance imaging (MRI). METHODS The arterial anatomy of the talus was studied in ten pairs of fresh-frozen cadaver limbs with use of gadolinium-enhanced MRI in addition to gross dissection following latex injection. MRI proved useful to confirm the presence of specific arterial branches in situ as well as to demonstrate the rich anastomosis network in and around the talus. We further examined the MRI studies to delineate the quantitative contribution of each of the three main arteries to the talus and to each quadrant of the talus (anteromedial [0], anterolateral [1], posterolateral [2], and posteromedial [3]). RESULTS The peroneal artery contributed 16.9% of the blood supply to the talus; the anterior tibial artery, 36.2%; and the posterior tibial artery, 47.0%. The contribution of the anterior tibial artery was greatest in quadrant 0, whereas the contribution of the posterior tibial artery was greatest in quadrants 1, 2, and 3. The peroneal artery did not make the greatest contribution in any quadrant. CONCLUSIONS In contrast to the findings in previous studies, we found that a substantial portion of the talar blood supply can enter posteriorly, which helps to explain why all talar neck fractures do not result in osteonecrosis. This finding, along with a very rich and redundant intraosseous pattern of anastomosis with contributions from all three vessels in each quadrant of the talus, may explain the low occurrence of osteonecrosis in association with talar neck fractures.

Acute pediatric upper extremity compartment syndrome in the absence of fracture.

Background: To determine the etiologies and outcomes associated with acute pediatric upper extremity compartment syndrome in the absence of fracture. Methods: A retrospective review was performed looking at children treated for acute upper extremity compartment syndrome in the absence of fracture at a major teaching hospital. Reason for admission, age, etiology, sensorium, time to fasciotomy, involved compartments, secondary procedures, and functional outcome were recorded. Results: A total of 14 extremities in 13 children with acute compartment syndrome in the absence of fracture were identified over a 22-year period at this single institution. There were 8 boys and 5 girls, with an average age of 7.2 years. Average follow-up was 22 months. Ten patients were being managed in the intensive care unit and had an obtunded sensorium. The cause was iatrogenic in 8 patients, and 2 of these resulted in loss of the involved limb. Six patients required 9 secondary procedures, including 4 amputations, 3 contracture releases, and 2 skin grafts. Of the 3 patients who required a total of 4 amputations, 2 of the patients were in the intensive care unit, and all were younger than 3 years. Only 7 patients had normal hand function. Upon comparing patients with a normal outcome versus those with an abnormal outcome, there was a statistically significant difference if surgery was performed in shorter than 6 hours (P = 0.033). Conclusions: This problem is often iatrogenic in etiology and can be diagnosed late in this population. An increased level of vigilance should be adopted for this entity because the final outcome can be catastrophic for both the patient and the hospital and early fasciotomy is associated with improved results. Level of Evidence: Level IV Case Series

Comparison of 4 airway devices on cervical spine alignment in a cadaver model with global ligamentous instability at C5-C6.

Study Design. Human cadaveric study using various intubation devices in a cervical spine instability model. Objective. We sought to evaluate various intubation techniques and determine which device results in the least cervical motion in the setting of a global ligamentous instability model. Summary of Background Data. Many patients presenting with a cervical spine injury have other injuries that may require rapid airway management with endotracheal intubation. Secondary neurologic injuries may occur in these patients because of further displacement at the level of injury, vascular insult, or systemic decrease in oxygen delivery. The most appropriate technique for achieving endotracheal intubation in the patient with a cervical spine injury remains controversial. Methods. A global ligamentous instability at the C5–C6 vertebral level was created in lightly embalmed cadavers. An electromagnetic motion analysis device (Liberty; Polhemus, Colchester, VT) was used to assess the amount of angular and linear translation in 3 planes during intubation trials with each of 4 devices (Airtraq laryngoscope, lighted stylet, intubating LMA, and Macintosh laryngoscope). The angular motions measured were flexion-extension, axial rotation, and lateral bending. Linear translation was measured in the medial-lateral (ML), axial, and anteroposterior planes. Intubation was performed by either an emergency medical technician or by a board-certified attending anesthesiologist. Both time to intubate as well as failure to intubate (after 3 attempts) were recorded. Results. There was no significant difference shown with regards to time to successfully intubate using the various devices. It was shown that the highest failure-to-intubate rate occurred with use of the intubating LMA (ILMA) (23%) versus 0% for the others. In flexion/extension, we were able to demonstrate that the Lightwand (P = 0.005) and Airtraq (P = 0.019) resulted in significantly less angular motion than the Macintosh blade. In anterior/posterior translation, the Lightwand (P = 0.005), Airtraq (P = 0.024), and ILMA (P = 0.021) all caused significantly less linear motion than the Macintosh blade. In axial rotation, the Lightwand (P = 0.017) and Airtraq (P = 0.022) resulted in significantly less angular motion than the Macintosh blade. In axial translation (P = 0.037) and lateral bending (P = 0.003), the Lightwand caused significantly less motion than the Macintosh blade. Conclusion. In a cadaver model of C5–C6 instability, the greatest amount of motion was caused by the most commonly used intubation device, the Macintosh blade. Intubation with the Lightwand resulted in significantly less motion in all tested parameters (other than ML translation) as compared with the Macintosh blade. It should also be noted that the Airtraq caused less motion than the Macintoshblade in 3 of the 6 tested planes. There were no significant differences in failure rate or the amount of time it took to successfully intubate in comparing these techniques. We therefore recommend the use of the Lightwand, followed by the Airtraq, in the setting of a presumed unstable cervical spine injury over the Macintosh laryngoscope.

Total motion generated in the unstable cervical spine during management of the typical trauma patient: a comparison of methods in a cadaver model.

Study Design. Biomechanical cadaveric study. Objective. We sought to analyze the amount of motion generated in the unstable cervical spine during various maneuvers and transfers that a trauma patient would typically be subjected to prior to definitive fixation, using 2 different protocols. Summary of Background Data. From the time of injury until the spine is adequately stabilized in the operating room, every step in management of the spine-injured patient can result in secondary injury to the spinal cord. Methods. The amount of angular motion between C5 and C6, after a surgically created unstable injury, was measured using an electromagnetic motion analysis device (Polhemus Inc., Colchester, VT). A total sequence of maneuvers and transfers was then performed that a patient would be expected to go through from the time of injury until surgical fixation. This included spine board placement and removal, bed transfers, lateral therapy, and turning the patient prone onto the operating table. During each of these, we performed what has been shown to be the best and commonly used (log-roll) techniques. Results. During bed transfers and the turn prone for surgery, there was statistically more angular motion in each plane for traditional transfer with the spine board and manually turning the patient prone as commonly done (P < 0.01). During spine board placement, there was more motion in all 3 planes with log-rolling, and this reached statistical significance for axial rotation (P = 0.015) and lateral bending (P = 0.004). There was more motion during board removal with log-rolling in all 3 planes. This was statistically significant for lateral bending (P = 0.009) and approached significance in flexion-extension (P = 0.058) and axial rotation (P = 0.058). During lateral therapy, there was statistically more motion in flexion-extension and lateral bending with the manual log-roll technique (P < 0.001). The total motion was decreased by more than 50% in each plane when using an alternative to log-roll techniques during the total sequence (P < 0.006). Conclusion. We have demonstrated the total angular motion incurred to the unstable cervical spine as experienced by the typical trauma patient from the field to stabilization in the operating room using the best compared with the most commonly used techniques. As previously reported, using log-roll techniques consistently results in unwanted motion at the injured spinal segment.

Management of nonunions of the proximal humeral diaphysis

It has been reported that the majority of nonunions of the humeral shaft evaluated are within the proximal one-third of the diaphysis. We are not aware of any reported series of humeral nonunions dealing specifically with the proximal diaphysis. We therefore sought to identify patients with a humeral shaft nonunion from an orthopaedic trauma service database, determine the frequency of those within the proximal one-third and review our treatment strategy and resulting clinical outcomes for these difficult fractures. Clinical and radiographical follow-up was available for 19 patients with a mean age of 70 years (range 29-94 years). This represented 46% of all humeral shaft nonunions treated during the study period. Dual plating was used in 11 cases to get adequate fixation in the proximal segment. Post-operative alignment was within 5° of anatomic in all cases. All nonunions healed at an average of 15.2 weeks (range 8-36 weeks). The mean length of follow-up was 12.5 months (range 6-122 months). All patients reported significant improvement in pain. The mean range of motion following fracture union was forward flexion 137°, external rotation 41° and internal rotation 30°. There were two minor complications and neither required a secondary surgery. The surgical technique we have used emphasising a thorough debridement of the nonunion site, correction of the deformity, fracture site compression with a rigid construct and bone grafting provides excellent rates of union and clinical outcomes.