No support for Heincke's law in hagfish (Myxinidae): lack of an association between body size and the depth of species occurrence.

This study tests for interspecific evidence of Heincke's law among hagfishes and advances the field of research on body size and depth of occurrence in fishes by including a phylogenetic correction and by examining depth in four ways: maximum depth, minimum depth, mean depth of recorded specimens and the average of maximum and minimum depths of occurrence. Results yield no evidence for Heincke's law in hagfishes, no phylogenetic signal for the depth at which species occur, but moderate to weak phylogenetic signal for body size, suggesting that phylogeny may play a role in determining body size in this group.

Incidence of clavicle fractures in sports: analysis of the NEISS Database.

Our goal was to present current data on the incidence of clavicle injuries presenting for urgent evaluation and to report the sports activities associated with injury. Using the National Electronic Injury Surveillance System (NEISS) database, the number of clavicle fractures presenting to a representative sample of U.S. hospitals was retrospectively calculated and weighted estimates used to extrapolate this data to the U.S. population. Incidence estimates were obtained using validated analyses and U.S. census data, with sports injuries being noted and fractures stratified by sport. A total of 9 428 fractures of the clavicle were reported, representing 357,155 injuries in the U.S. population over 5 years. The estimated incidence of clavicle fractures in the U.S. presenting for emergency care is 24.4 fractures per 100,000 person-years (95% confidence intervals (CI), 22.8-26.1). The peak incidence was highest between ages 10-19 years. Men were nearly 3 times as likely to sustain a clavicle fracture. Sports were a factor in 45% of all clavicle fractures. In sports-related injuries, 16% of fractures occurred from bicycling, followed by football (12%) and soccer (6%). In summary, injuries from bicycling were the most common cause of clavicle fracture, followed by contact sports. Male gender and younger age are risk factors for clavicle fractures.

The floating shoulder.

The floating shoulder is defined as ipsilateral fractures of the midshaft of the clavicle and the neck of the glenoid. This rare injury can be difficult to manage without a thorough understanding of the complex anatomy of the shoulder girdle. Surgical intervention needs to be considered for all of these injuries. While acceptable results can be expected with non-operative management of minimally-displaced fractures, displacement at one or both sites is best managed with surgical reduction and fixation.

Effectiveness of commercially-available antibiotic-impregnated implants.

The aim of this study was to determine the effectiveness of antibiotic-impregnated implants in the prevention of bone infection. We used a model of contaminated fracture in goats to evaluate four treatment groups: no treatment, hand-made tobramycin-impregnated polymethylmethacrylate beads, commercially-available tobramycin-impregnated calcium sulphate pellets and commercially-available tobramycin-impregnated polymethylmethacrylate beads. Three weeks after intraosseous inoculation with streptomycin-resistant Staphylococcus aureus tissue cultures showed no evidence of infection in any of the antibiotic-treated groups. All of the cultures were positive in the untreated group. These results show that effective local antibiotic delivery can be obtained with both commercially-available products and with hand-made polymethylmethacrylate beads. The calcium sulphate pellets have the advantage of being bioabsorbable, thereby obviating the need for a second procedure to remove them.

Arthroscopic release for lateral epicondylitis.

PURPOSE: This study was performed to review the results of our early experience with recalcitrant lateral epicondylitis treated arthroscopically. TYPE OF STUDY: This study is a case series consisting of consecutive patients with lateral epicondylitis treated arthroscopically by 1 surgeon. METHODS: Patients failing a minimum of 6 months of conservative treatment underwent arthroscopic release of the extensor carpi radialis brevis (ECRB) origin using the proximal medial and proximal lateral portals. Associated intra-articular pathology was noted and addressed. The ECRB lesions were classified according to their gross morphology and resected with a shaver. The lateral epicondyle was then decorticated with a burr. RESULTS: Sixteen patients with recalcitrant lateral epicondylitis were treated with arthroscopic release of the ECRB origin on the lateral epicondyle. Of the 16 elbows undergoing surgery, 5 (31.3%) were noted to have a type I lesion, characterized as fraying of the undersurface of the ECRB. Five (31.3%) had a type II lesion noted by linear tears within the ECRB, and 6 (37.5%) had a type III lesion, consisting of a partial or complete avulsion of the ECRB origin. Concurrent intra-articular pathology (synovitis, osteophytes) was noted in 3 of 16 elbows (18.8%) and was addressed arthroscopically. All patients were followed-up for a minimum of 1 year; however, 4 patients were lost to follow-up for this retrospective review due to military reassignment. Follow-up was obtained on 12 of 16 (75%) of patients at an average length of 24.1 months (range, 15 to 33 months). All patients reported improvement with the procedure. The average return to unrestricted work was 6.0 days (range, 0 to 28 days). CONCLUSIONS: Arthroscopic release effectively treats lateral epicondylitis while also affording visualization of the joint space to address associated intra-articular pathology. Additionally, arthroscopic release is minimally invasive and allows early rehabilitation and return to normal activities.

Lumbar sagittal contour after posterior interbody fusion: threaded devices alone versus vertical cages plus posterior instrumentation.

STUDY DESIGN: An observational radiographic study examining lumbar sagittal contour of patients undergoing posterior interbody arthrodesis. OBJECTIVES: To compare operative alterations of lumbar sagittal contour after posterior interbody fusion using threaded interbody devices alone versus vertical cages combined with posterior compression instrumentation. SUMMARY OF BACKGROUND DATA: Technique-related alterations of lumbar sagittal contour during interbody arthrodesis have received little attention in the spinal literature. METHODS: Standing lumbar radiographs were measured for preoperative and postoperative segmental lordosis at levels undergoing posterior interbody arthrodesis using either stand-alone side-by-side threaded devices or vertical cages combined with posterior transpedicular compression instrumentation. Sagittal plane segmental correction (or loss of correction) was calculated and statistically compared. RESULTS: The radiographs of 30 patients (34 spinal segments) undergoing lumbar or lumbosacral arthrodesis were compared. Seventeen patients (18 segments) had undergone interbody fusion using threaded cages,whereas 13 patients (16 segments) underwent fusion using vertically oriented mesh cages combined with posterior compression instrumentation. Preoperative segmental lordosis averaged 8 degrees for both groups. For patients undergoing fusion with threaded cages, there was a mean lordotic loss of 3 degrees/segment. For patients undergoing fusion with vertically oriented mesh cages combined with posterior compression instrumentation,there was a mean lordotic gain of 5 degrees/segment. This difference in segmental sagittal plane contour was highly significant (P = 0.00). CONCLUSION: Threaded fusion devices placed under interbody distraction with the endplates parallel fail to preserve or reestablish segmental lordosis. Vertical cages, however, when combined with posterior compression instrumentation, not only maintain segmental lordosis, but also can correct sagittal plane deformity.

Femoral nerve block with 0.25% or 0.5% bupivacaine improves postoperative analgesia following outpatient arthroscopic anterior cruciate ligament repair.

BACKGROUND AND OBJECTIVES: Femoral nerve block is effective in reducing postoperative pain after inpatient knee surgery. We studied its efficacy compared with standard analgesia following outpatient anterior cruciate ligament repair, including the duration of analgesia and the effect of different concentrations of bupivacaine. METHODS: After Institutional Review Board approval and informed consent, we prospectively randomized patients to receive, in a blinded fashion, either a sham block, a femoral nerve block with 25 mL 0.25% bupivacaine, or with 25 mL 0.5% bupivacaine after anterior cruciate ligament repair under epidural anesthesia. Verbal analog pain scores were evaluated by a blinded observer at 20 and 40 minutes after injection. Patients with pain >4 (out of 10) were assessed for the presence of a block and offered a supplemental block if no anesthesia was present at either evaluation. By prospective agreement, any study group with 6 failures was excluded from further recruitment. After discharge, patients recorded pain scores and analgesic consumption in a diary, and estimated the time at which they perceived that analgesia and sensory block from the femoral nerve block resolved, based on an increase in pain, sensation, and strength in the leg. RESULTS: In the sham block group, 6 of 12 patients reported inadequate analgesia in the postanesthesia care unit (4 at 20 minutes, 2 at 40 minutes; greater than other groups, P <.003) and were excluded from further study. Patients with sham blocks had higher pain scores 20 minutes after the block, and requested intravenous analgesia more often. Bupivacaine 0.25% and 0.5% provided 23.2 +/- 7 and 25.7 +/- 11 hours of analgesia, respectively. CONCLUSIONS: Femoral nerve block with 0.25% bupivacaine contributes significantly to multimodal postoperative analgesia in the immediate postoperative period following outpatient anterior cruciate ligament repair. Both doses of bupivacaine studied provided analgesia for the first night after surgery.

Measurement of thoracic and lumbar fracture kyphosis: evaluation of intraobserver, interobserver, and technique variability.

STUDY DESIGN: Statistical analysis of various measurement techniques for thoracolumbar burst fracture kyphosis on lateral radiograph. OBJECTIVE: To determine the most reliable measurement technique. SUMMARY OF BACKGROUND DATA: The treatment of thoracic and lumbar burst fractures involves many factors, including the degree of resultant kyphosis. Although various methods have been described, no study has directly compared these methods for reliability and reproducibility. METHODS: Fifty lateral radiographs of thoracic and lumbar burst fractures were randomly selected and measured on two separate occasions by three spine surgeons using five different measurement techniques. Radiograph quality, fracture type, and the center beam location were determined. Statistical analysis included analysis of variance for repeated measures and analysis of variance using a generalized linear model. RESULTS: Intraclass correlation coefficients were most consistent for Method 1 (rho = 0.83-0.94) followed by Method 4 (rho = 0.65-0.89) and Method 5 (rho = 0.73-0. 85). Intraobserver agreement (% of repeated measures within 5 degrees of the original measurement) ranged between 72% and 98% for all techniques for all three observers, with Method 1 showing the best agreement (84%-98%). Paired comparisons between observers varied considerably with interobserver reliability correlation coefficients ranging from 0.52 to 0.93. Method 1 showed the highest interobserver reliability coefficient (0.81, range 0.71-0.93) followed by Method 5 (0.71, range 0.68-0.75). Method 1 also had the highest percentage of agreement within categories (90% within 5 degrees ). CONCLUSIONS: Method 1 (measuring from the superior endplate of the vertebral body one level above the injured vertebral body to the inferior endplate of the vertebral body one level below) showed the best intraobserver and interobserver reliability overall.

Langerhans' cell histiocytosis in patients older than 21 years.

In this retrospective review of 541 patients with Langerhans' cell histiocytosis, 211 (39%) patients were older than 21 years of age, whereas 330 (61%) were younger than 21 years of age. The adult patients had a mean age of 32 years (range, 21-69 years) with 159 (75%) men and 52 (25%) women, whereas the pediatric patients consisted of 176 (55%) boys and 144 (45%) girls. This male predominance in adults was statistically significant. Three adults had the Hand-Schuller-Christian variant, whereas the remaining adults (208) had eosinophilic granuloma. The rib accounted for 25% of the adult lesions and only 8% of the pediatric lesions. Spine involvement was less common in the adult group (3% versus 10%) and was predominantly thoracic. The adult patients had 40 (77%) diaphyseal lesions, 12 (23%) metaphyseal lesions, and no epiphyseal lesions. The pediatric patients had 75 (54%) diaphyseal, 59 (42%) metaphyseal, and five (4%) epiphyseal lesions. Radiographic evaluation revealed similar margin and matrix patterns in both groups, with a geographic lesion without sclerotic borders being the most common pattern. Langerhans' cell histiocytosis is considered a pediatric disease. However, this study showed a significant number (39%) of patients older than 21 years of age with this condition.

Peripheral nerve blocks improve analgesia after total knee replacement surgery.

UNLABELLED: Total knee replacement (TKR) produces severe postoperative pain. Peripheral nerve blocks can be used as analgesic adjuncts for TKR, but the efficacy of femoral nerve blocks alone is controversial. The sciatic nerve innervates posterior regions of the knee; thus, performance of both sciatic and femoral nerve blocks may be necessary to improve analgesia after TKR. We performed this study to determine whether peripheral nerve blocks improve analgesia after TKR. In a randomized, double-blind fashion, 36 patients undergoing TKR received either femoral, sciatic-femoral, or sham nerve blocks after a standardized spinal anesthetic. Further postoperative analgesia was provided by patient-controlled i.v. morphine and ketorolac. Pain at rest and with physical therapy, morphine use, nausea, pruritus, sedation, and patient satisfaction were assessed. Patients receiving peripheral nerve blocks reported better analgesia at rest for at least 8 h after transfer to the hospital ward (P < 0.05). Morphine use was decreased by approximately 50% in the peripheral nerve block groups until the second postoperative day (P < 0.02). Side effect profiles and patient satisfaction were similar between groups. We conclude that femoral nerve blocks improve analgesia and decrease morphine use after TKR. The addition of a sciatic nerve block to the femoral nerve block did not further improve analgesic efficacy. IMPLICATIONS: Performance of femoral nerve blocks improves analgesia and decreases the need for morphine after total knee replacement surgery. The addition of a sciatic nerve block to the femoral nerve block does not provide additional benefits.

Effects of epidural bupivacaine after thoracotomy.

BACKGROUND AND OBJECTIVES: Combinations of bupivacaine and fentanyl are popular for postoperative epidural analgesia. However, there are little data from which to select a rational dose of bupivacaine. The study examined the effects of increasing amounts of epidural bupivacaine on postoperative analgesia, epidural fentanyl consumption, and side effects after thoracotomy. METHODS: Twenty-four patients were randomized in a double-blind manner to receive intra- and postoperative epidural infusions of either saline, 0.01% bupivacaine, 0.05% bupivacaine, or 0.1% bupivacaine at 10 mL/h. All patients received a standardized combined epidural (120 mg lidocaine and 1.5 micrograms/kg of fentanyl) and general anesthesia. Further postoperative analgesia was provided with fentanyl patient-controlled epidural analgesia (PCEA) only. RESULTS: There were no differences between groups in visual analog scale (VAS) pain scores at rest or cough, but 10 and 5 mg/h of bupivacaine provided better analgesia during physiotherapy (P < .05). The use of 10 and 5 mg/h of bupivacaine led to significant opioid sparing (50% decrease) when compared to saline and 1 mg/h bupivacaine (P < .03). There was a trend toward a greater incidence of orthostasis with the use of bupivacaine at 10 mg/h (P = .09). Incidences of opioid side effects were not different between groups. CONCLUSIONS: The results demonstrate improved analgesia with physiotherapy and significant opioid sparing when 10 and 5 mg/h doses of bupivacaine are used. However, the incidence of orthostasis may be increased with the use of 10 mg/h. Thus, 5 mg/h of epidural bupivacaine (.05% at 10 mL/h) improved analgesia, decreased opioid requirements, and did not have detectable hemodynamic effects.

Lidocaine 0.5% spinal anaesthesia: a hypobaric solution for short-stay perirectal surgery.

The efficacy of subarachnoid injection of 8 ml lidocaine 0.5% was assessed in ten outpatients having perirectal surgery in the jackknife position. This solution is hypobaric, with a baricity 0.9985 +/- 0.0003 (mean +/- SD). Injections were made with the patient in the surgical position (with the upper torso at a 15 degrees downward inclination). Sensory level was tested by pinprick. Times to two-segment regression, to complete resolution of sensory analgesia, to urination, and to discharge from the recovery room were recorded. All injections produced effective anaesthesia for surgery. Lidocaine 0.5% behaves clinically as a hypobaric solution. Dermatomal levels remained low (T11 to L5) while the patients were in the surgical position (head down), but rose two to six dermatomes if the patient's head was elevated after surgery. Time to two-segment regression was 97 +/- 36 min, time until regression to S1 was 116 +/- 22 min, time to complete resolution of sensory blockade was 151 +/- 23 min, time to urination was 197 +/- 64 min, and time to discharge from the recovery room was 205 +/- 45 min. Lidocaine 0.5% provides effective spinal anaesthesia of short duration appropriate for outpatient surgical procedures. Dermatomal sensory spread of anaesthesia, and our measurements of specific gravity, indicate that this solution is hypobaric. It appears that changes in position can alter the spread of analgesia for at least one hour after injection and, thus, we caution against elevating the patient's head in the immediate postoperative period.

Comparison between ropivacaine and bupivacaine after subcutaneous injection in pigs: cutaneous blood flow and surgical bleeding.

In this randomized, blinded study, we sought to determine whether the vasoconstriction produced by ropivacaine after subcutaneous injection is sufficient to decrease surgical bleeding. Anesthesia was induced in seven piglets (weight, 12.2-20.4 kg) with intraperitoneal thiopental and maintained with intravenous methohexital. Five sites were injected with 10 ml of one of the following solutions: 0.25% ropivacaine, 0.25% bupivacaine, either solution plus 5 micrograms/ml epinephrine, or saline. Another site was left uninjected for control. Capillary blood flow was measured at each site with a laser Doppler before and ten minutes after the injections. An incision 5 cm in length was then made through the dermis, and blood loss was measured over ten minutes. We found no significant differences in capillary blood flow and blood loss between bupivacaine and ropivacaine. Addition of epinephrine decreased capillary blood flow (p less than 0.05) and tended to decrease blood loss. Capillary blood flow correlated with blood loss (r2 = 0.106; p less than 0.05). We conclude that, in contrast to previous studies, ropivacaine did not decrease capillary blood flow in our model. Similarly, ropivacaine did not reduce bleeding from surgical incisions. The reason for these surprising results is not clear but is unlikely to be the larger volume of solutions injected because no such effect was observed with saline alone.