Effect of K-wire Reuse and Drill Mode on Heat Generation in Bone.

BACKGROUND: We examined the effect of Kirschner wire (K-wire) reuse and use of oscillating mode on heat generation within cortical bone. METHODS: Two trocar-tipped K-wires were drilled through the diaphysis of each of 30 human metacarpals and phalanges: one K-wire was inserted in rotary mode and another in oscillating mode. Each wire was reused once. Thermocouples placed within the dorsal and volar bone adjacent to the K-wire drill path measured temperatures throughout each test. RESULTS: Peak cortex temperatures were 25°C to 164°C. Rotary drilling achieves peak temperatures quicker (31 ± 78 seconds vs 44 ± 78 seconds, P = .19) than oscillating drilling, but insertion time is also less, resulting in lower overall heat exposure. This effect is also seen when the K-wire is reused (34 ± 70 seconds vs 41 ± 85 seconds, P = .4). The length of time that cortical bone was exposed to critical temperatures (47°C or more) was significantly higher when a wire was reused (36 ± 72 seconds vs 43 ± 82 seconds, P = .008). Peak temperatures greater than 70°C (a temperature associated with instantaneous cell death) were observed on many occasions. CONCLUSIONS: Overall heat exposure may be higher if a K-wire is reused or inserted in oscillating mode. In the absence of external cooling, K-wire insertion into cortical bone can easily expose bone to temperatures that exceed 70°C and may increase the risk of osteonecrosis.

Tumor-induced osteomalacia - Current imaging modalities and a systematic approach for tumor localization.

Paraneoplastic syndromes are symptom complexes that cannot be readily explained by local or distant spread of the tumor. They can occur due to hormone production, autoimmunity or other biologically active products produced by the tumor, etc. Tumor induced osteomalacia is a rare paraneoplastic syndrome in which the manifestation is mainly musculoskeletal such as bone pain, fractures and muscle weakness as a consequence of elaboration of fibroblast growth factor 23 (FGF23) by the tumor. Most of these tumors are solitary and small and hence localization of these tumors is often challenging. This review summarizes the various anatomic imaging modalities such as plain radiographs, computed tomography (CT), and magnetic resonance imaging (MRI) and nuclear medicine imaging techniques in the evaluation of these tumors.

Blood pressure measurement in the geriatric population.

As the population above 60 years of age is the fastest growing and hypertension is highly prevalent in this group, accurate blood pressure (BP) measurement in the elderly is a very important and widely applicable subject. As with any other population, an accurate measurement of BP is essential to plan therapy and this remains an important consideration in the elderly as well. There are some unique problems of BP measurement in the elderly, including drug-induced orthostatic hypotension, white-coat hypertension, and advanced atherosclerotic disease with stiff arteries. For clinical use, home blood pressure monitoring (HBPM), office measurement, and ambulatory blood pressure monitoring all play a role in patient management. In the office setting, aneroid devices, hybrid devices with electronic transducers, and oscillometric devices are available; all of these require frequent calibration, well-trained operators and technically sound execution. Because the white-coat effect is common in this group, there is a good case for the use of HBPM, which could also be used to detect orthostatic changes at home. Also, HBPM predicts cardiovascular events better than clinical BP, and is also useful in monitoring treatment. Ambulatory blood pressure monitoring provides the most precise assessment of BP over an extended period, but is more complex and expensive. Finally, the utility of noninvasive central arterial pressure through radial artery applanation tonometry, especially in patients with resistant hypertension and likely in the elderly because of advanced atherosclerotic disease and stiff arteries, may prove to be a useful tool to guide or modify drug therapy in the future and requires further study.

Resident surgical practice patterns for vitreoretinal surgery in ophthalmic training programs in the United States.

PURPOSE: To assess resident surgical experience in vitreoretinal surgery (VRS) in the United States. DESIGN: Anonymous electronic survey over 2 consecutive years. PARTICIPANTS: A total of 287 third-year ophthalmology residents from US residency programs were included. METHODS: To determine the type and amount of surgical experience in VRS. Residents were contacted via e-mail to complete the survey. A series of follow-up e-mails were sent to nonresponders. E-mail correspondence was sent to program directors of the US residency programs to encourage survey participation. An electronic survey instrument (Survey Monkey) was used to distribute the survey and collect the results. Participants were asked about vitrectomy and scleral buckle procedures as primary surgeon and about office procedures (e.g., intravitreal injections and retinal laser procedures). Questions regarding the self-described "comfort" level of the resident and the Accreditation Council for Graduate Medical Education (ACGME) vitreoretinal requirements for ophthalmology were also included. MAIN OUTCOME MEASURES: Vitreoretinal office and surgical procedures. RESULTS: Of the 114 ophthalmology residency programs in the United States, 3 programs declined to participate and 103 of 228 programs (114 programs per year) did not respond to requests during a 2-year period. Of the 287 total respondents, approximately 59.1% had performed vitrectomy and 40.8% had performed a scleral buckle as the primary surgeon. In the survey of office procedures, 96.7% had performed intravitreal injections, 94.8% had performed macular laser therapy, and 99.6% had performed panretinal photocoagulation. In the self-reported resident "comfort" level section, 59% were "fairly comfortable" knowing the theoretic steps for VRS and 55.4% were "fairly satisfied" with VRS training. However, 72% of respondents were unaware of the correct ACGME minimum operative numbers for VRS. CONCLUSIONS: This self-reported electronic survey of third-year residents suggested that VRS experience at ACGME-accredited programs as primary surgeon was suboptimal for surgeries. A modest majority of residents reported comfort and satisfaction with VRS training for surgery, but a majority was satisfied and had adequate experience with office procedures such as intravitreal injection and laser treatment. Unfortunately, the majority of residents were unaware of the actual numeric ACGME VRS requirements for ophthalmology residency programs.

Utility of MR imaging in cat-scratch neuroretinitis.

About 80% of cat-scratch disease (CSD) infections occur in children, and CSD neuroretinitis (optic neuropathy with retinal exudates in a "macular star" pattern) mostly occurs in children and young adults. A recent study suggested that CSD optic neuropathy has specific features on MR imaging. However, MR imaging findings in CSD neuroretinitis are not well described in the pediatric literature. We present a patient with CSD neuroretinitis in whom these specific MR imaging features preceded the macular star, a funduscopic finding strongly suggestive of neuroretinitis. This case demonstrates how knowledge of these features is important in the appropriate diagnostic work-up of optic neuropathy. MR imaging also incidentally revealed neuritis of another cranial nerve in the auditory canal-a rare manifestation of CSD.