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ABSTRACT: The utilization of peripheral nerve blocks in orthopaedic surgery has paralleled the rise in the number of ambulatory surgical procedures performed. Optimization of pain control in the perioperative orthopaedic patient contributes to improved patient satisfaction, early mobilization, decreased length of hospitalization, and decreased associated hospital and patient costs. Our purpose was to provide a concise, pertinent review of the use of peripheral nerve blocks in various orthopaedic procedures of the lower extremity, with specific focus on procedural anatomy, indications, patient outcome measures, and complications.
We reviewed the literature and reference textbooks on commonly performed lower-extremity peripheral nerve block procedures in orthopaedic surgery, focusing on those most commonly used.
The use of lower-extremity peripheral nerve blocks is a safe and effective approach to perioperative pain management. Different techniques and timing can have an important impact on patient satisfaction, and each technique has specific indications and complications. For major hip surgery, one of the most commonly used is the lumbar plexus block, which can result in early mobilization, reduced postoperative pain, and decreased opioid-associated adverse events. Associated complications include epidural spread of anesthesia, retroperitoneal hematoma formation, and postoperative falls. For arthroscopic and open knee procedures, the femoral nerve block is frequently used adjunctively. It provides improved early postoperative pain control, early mobilization with therapy, and increased patient satisfaction compared with intra-articular or intravenous opioids alone; it also provides cost savings. However, some studies have shown no significant difference in outcome measures compared with intra-articular opioids alone for arthroscopic anterior cruciate ligament reconstruction. Associated complications include nerve injury, intravascular injection, and postoperative falls.
The use of peripheral nerve blocks in lower-extremity surgery is becoming a mainstay of perioperative pain management strategy.
The Journal of Bone and Joint Surgery 11/2012; 94(22):e1671-13. · 3.27 Impact Factor
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ABSTRACT: Tears of the proximal long head of the biceps tendon are among the most common tendon tears in the body. In most cases, the diagnosis is easily determined based on the history and physical examination. However, malignant soft tissue tumors can simulate proximal biceps tendon tears. Although tumors simulating tears of the distal biceps tendon at the elbow have been reported, to the authors' knowledge, no previous cases of tumors simulating or being mistaken for proximal biceps tendon tears have been reported.This article describes 2 cases of malignant sarcomas initially mistaken for tears of the long head of the biceps tendon. In the first case, a 62-year-old woman developed swelling in her arm after feeling a twinge in her shoulder. A magnetic resonance imaging scan was misread as a biceps tendon tear and not treated by the examining physician. In the second case, a mass appeared with little trauma in the brachium of a 70-year-old man. On physical examination, the mass was hard to palpation. In each case, biopsy revealed a soft tissue sarcoma. Both patients underwent wide excision with radiation and are currently disease free. These 2 cases emphasize the importance of obtaining a good history and of performing a thorough shoulder and arm examination in patients with deformities consistent with tears of the long head of the biceps tendon.
Orthopedics 10/2012; 35(10):e1548-52. · 2.66 Impact Factor
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ABSTRACT: The need for accuracy in neurovascular examinations of the extremities of trauma patients is well recognized. The goals of this study were to (a) evaluate the completeness of orthopedic house staff documentation of the neurovascular status of adult patients with extremity trauma, (b) identify the frequency of individual element documentation, and (c) determine if completeness was related to experience. The trauma center's database was reviewed for patients with extremity injuries (June 2006 through January 2008). For 114 patients, the authors assessed the neurovascular examination documentation for completeness (sensory, motor function, and vascular elements) and "perfection" (complete bilateral elements), identified the frequency of individual element documentation, and determined the relationship of completeness to experience (Pearson correlation coefficients; significance, P ≤ .05). There was no complete (all elements) or perfect (complete bilateral) documentation. The element most often documented completely was the sensory examination. Increased examiner experience was significantly associated with decreased sensory and vascular documentation.
American Journal of Medical Quality 07/2012; · 1.64 Impact Factor
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ABSTRACT: Various pin configurations have been recommended for the treatment of supracondylar humerus fractures on the basis of the choice between stability versus the risk of iatrogenic nerve injury. However, little attention has been paid to pin size. The purpose of this study was to evaluate the stability of large (2.8 mm or 0.110 inch) and small (1.6 mm or 0.062 inch) pin constructs in 6 configurations.
A transverse fracture pattern was created by sectioning synthetic humeri in the midolecranon fossa. The specimens were then reduced and pinned in one of 6 configurations: 2 small pins (Kirschner wires) placed crossed or lateral divergent, 2 large pins (Steinmann pins) placed crossed or lateral divergent, or 3 small pins placed crossed or lateral divergent. All specimens were then tested in sagittal extension bending. We investigated the effect of pin configuration and cycle on the sagittal stiffness using multiple linear regression.
The 2 small lateral divergent pin configuration was significantly less stable than small crossed pins and large pins in a crossed or a lateral configuration. The addition of a third (lateral) pin to the small crossed pin construct made it significantly less stable than 2 large crossed pins. Although the stability between the remaining configurations was not significantly different, the 2 large crossed pins required the greatest torque to rotate the fragment 20 degrees. There was a significant reduction in torque as a function of cycle, suggesting a loss of fixation during cycling (P<0.05).
Large pins (2.8 mm) in any configuration and the placement of small pins (1.6 mm) in a crossed configuration provided more stable reduction in sagittal extension bending than did the conventional 2 small pins in a lateral divergent pin configuration. The most stable configurations involve crossing the medial and lateral pins.
There are more stable options than the traditional 2 small lateral pin configuration for fixation of unstable supracondylar fractures. The addition of a third pin is not always advantageous.
Journal of pediatric orthopedics 03/2012; 32(2):201-5. · 1.23 Impact Factor
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ABSTRACT: No study examining pin constructs has adequately addressed pin size and its role in fracture fixation. Our goal was to review our experience with Wilkins-modified Gartland type-III pediatric supracondylar humerus fractures treated with closed reduction and percutaneous pinning to evaluate the effects of pin size within 2 different pin constructs on maintenance of reduction and on the risk of surgical complications.
We retrospectively reviewed the medical records of pediatric patients with Wilkins-modified Gartland type-III supracondylar humerus fractures that were closed reduced and percutaneously pinned at our institution from March 1999 through December 2008. We grouped those 159 patients by fracture stabilization method (lateral-entry-pin or crossed-pin constructs), by pin size ratio (ie, ratio of pin diameter to the humeral midshaft cortical thickness: small ≤0.9; large >0.9), and then by 4 combinations of pin construct and pin size ratio. For each group, we evaluated radiographs for immediate postoperative reduction (coronal and sagittal alignment), maintenance of reduction at last follow-up, and the number of surgical complications. We used the Student t test, χ² test, Mann-Whitney U test, and Wilcoxon Signed Rank test to examine for significance, which was set at P<0.05.
Although we found no significant differences between the groups immediately after surgery, final follow-up sagittal alignment was significantly more likely to be maintained in the large pin size ratio group than in the small pin size ratio group. For 2 types of surgical complications, infection and nerve palsy, we found no statistically significant differences in these complications between the pin construct or pin size ratio groups.
Large pin sizes improved radiographic sagittal alignment at final follow-up without an increased rate of infection or ulnar nerve palsy.
Level III Therapeutic Study.
Journal of pediatric orthopedics 12/2010; 30(8):792-8. · 1.23 Impact Factor
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Journal of shoulder and elbow surgery / American Shoulder and Elbow Surgeons ... [et al.] 02/2010; 19(3):e20-4. · 1.93 Impact Factor
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ABSTRACT: In animals with active sensory systems, group size can have dramatic effects on the sensory information available to individuals. In "wave-type" weakly electric fishes there is a categorical difference in sensory processing between solitary fish and fish in groups: when conspecifics are within about 1m of each other, the electric fields mix and produce interference patterns that are detected by electroreceptors on each individual. Neural circuits in these animals must therefore process two streams of information-salient signals from prey items and predators and social signals from nearby conspecifics. We investigated the parameters of social signals in two genera of sympatric weakly electric fishes, Apteronotus and Sternopygus, in natural habitats of the Napo River valley in Ecuador and in laboratory settings. Apteronotus were most commonly found in pairs along the Napo River (47% of observations; maximum group size 4) and produced electrosensory interference at rates of 20-300 Hz. In contrast, Sternopygus were alone in 80% of observations (maximum group size 2) in the same region of Ecuador. Similar patterns were observed in laboratory experiments: Apteronotus were in groups and preferentially approached conspecific-like signals in an electrotaxis experiment whereas Sternopygus tended to be solitary and did not approach conspecific-like electrosensory signals. These results demonstrate categorical differences in social electrosensory-related activation of central nervous system circuits that may be related to the evolution of the jamming avoidance response that is used in Apteronotus but not Sternopygus to increase the frequency of electrosensory interference patterns.
Behavioural brain research 10/2009; 207(2):368-76. · 3.22 Impact Factor
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ABSTRACT: The detection and identification of behaviorally relevant signals in the presence of competing signals in the environment is a major challenge of animal sensory systems. In weakly electric fish such as Eigenmannia virescens, the interactions between the autogenous electric field and the electric fields of nearby conspecifics can have profound effects on the perception of other behaviorally relevant electrosensory information. To better understand the natural signals that the nervous system of Eigenmannia experiences during the processing of electrosensory information, we examined the electrosensory milieu of Eigenmannia in the wild and in the laboratory. Recordings of the electric fields of Eigenmannia were made in 'black' and 'white' waters near the Napo River in eastern Ecuador. Fourier analysis revealed that Eigenmannia typically experience the electric fields of three to five conspecifics during the day and night in each habitat. The median difference in electric organ discharge frequencies between nearby Eigenmannia during the day was 23 Hz in black water habitats, 41 Hz in white water, and 37 Hz at night in both habitats: these signals are known to activate tuberous electroreceptors and downstream CNS circuits. There was no correlation between the number of individual Eigenmannia detected at recording sites and electric organ discharge frequencies. Further, Eigenmannia apparently do not maximize the frequency differences between conspecifics. In laboratory studies fish were preferentially observed in aggregates of two fish or more. Aggregate sizes observed in the laboratory were similar to those in the wild.
Behavioural Brain Research 11/2005; 164(1):83-92. · 3.42 Impact Factor
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ABSTRACT: Wave-type weakly electric fish such as Eigenmannia produce continuous sinusoidal electric fields. When conspecifics are in close proximity, interaction of these electric fields can produce deficits in electrosensory function. We examined a neural correlate of such jamming at the level of the midbrain. Previous results indicate that neurons in the dorsal layers of the torus semicircularis can (1) respond to jamming signals, (2) respond to moving electrosensory stimuli, and (3) receive convergent information from the four sensory maps of the electrosensory lateral line lobe (ELL). In this study we recorded the intracellular responses of both tuberous and ampullary neurons to moving objects. Robust Gaussian-shaped or sinusoidal responses with half-height durations between 55 ms and 581 ms were seen in both modalities. The addition of ongoing global signals with temporal-frequencies of 5 Hz attenuated the responses to the moving object by 5 dB or more. In contrast, the responses to the moving object were not attenuated by the addition of signals with temporal frequencies of 20 Hz or greater. This occurred in both the ampullary and tuberous systems, despite the fact that the ampullary afferents to the torus originate in a single ELL map whereas the tuberous afferents emerge from three maps.
Journal of Comparative Physiology 10/2005; 191(9):865-72. · 2.01 Impact Factor
