Optimizing multiphoton fluorescence microscopy light collection from living tissue by noncontact total emission detection (epiTED)

A benefit of multiphoton fluorescence microscopy is the inherent optical sectioning that occurs during excitation at the diffraction-limited spot. The scanned collection of fluorescence emission is incoherent; that is, no real image needs to be formed on the detector plane. The nearly isotropic emission of fluorescence excited at the focal spot allows for new detection schemes that efficiently funnel all attainable photons to detector(s). We previously showed [Combs, C.A., et al. (2007) Optimization of multiphoton excitation microscopy by total emission detection using a parabolic light reflector. J. Microsc. 228, 330-337] that parabolic mirrors and condensers could be combined to collect the totality of solid angle around the excitation spot for tissue blocks, leading to ∼8-fold signal gain. Using a similar approach, we have developed an in vivo total emission detection (epiTED) instrument modified to make noncontact images from outside of living tissue. Simulations suggest that a ∼4-fold enhancement may be possible (much larger with lower NA objectives than the 0.95 NA used here) with this approach, depending on objective characteristics, imaging depth and the characteristics of the sample being imaged. In our initial prototype, 2-fold improvements were demonstrated in the mouse brain and skeletal muscle as well as the rat kidney, using a variety of fluorophores and no compromise of spatial resolution. These results show this epiTED prototype effectively doubles emission signal in vivo; thus, it will maintain the image signal-to-noise ratio at two times the scan rate or enable full scan rate at approximately 30% reduced laser power (to minimize photo-damage).

Intrafocal (Kapandji) pinning of unstable distal radius fractures: a preliminary report

Seventeen consecutive patients (17 wrists) who underwent intrafocal pinning of unstable distal radius fractures, as described by Kapandji, were retrospectively reviewed at a mean of 42 weeks after surgery (range, 13-88 weeks). The patients were immobilized for 6 weeks postoperatively. All patients were assessed by a single physician and were asked a set of questions regarding subjective and functional status. All patients underwent physical examination of their upper extremities, and bilateral wrist PA and lateral x-rays were taken. There were 13 females and four males; the average age was 49 years. Ten dominant and seven nondominant extremities were involved. Average volar tilt on follow-up lateral wrist radiography was 7 degrees. This compares with -20 degrees at initial presentation, -12 degrees preoperatively, 6 degrees immediately postoperatively, and 10 degrees in the normal wrists. Radial shortening (average) was -2 mm at initial presentation, -1mm preoperatively, 1 mm postoperatively, 0 mm at follow-up, and 1 mm in the normal wrists. Radial inclination was 17 degrees initially, 20 degrees preoperatively, 23 degrees immediately postoperatively, 23 degrees on follow-up, and 24 degrees in the normal wrists. There was a trend for patients with osteopenic bone to lose their postoperative reduction. However, this was not statistically significant. Patients older than 65 years of age had significantly inferior radiologic results. Loss of pronation and supination averaged 2 degrees (range 0-10 degrees) compared with the uninjured wrist. Loss of dorsiflexion averaged 6.5 degrees, and palmar flexion averaged 7.6 degrees. The patients' subjective complaints were minimal. Average pain on visual analog scale (VAS) was 0.44/10. Function measured 8.64/10 (VAS). Sixteen of the patients were happy with the surgery and the outcome of their wrists. Complications included extensor tendon rupture (one patient), pin migration requiring premature removal (one patient), and initial loss of reduction requiring reoperation (one patient). Intrafocal pinning of unstable distal radius fractures provides an effective means to stabilize these complex injuries. Early follow-up suggests that the patients have a satisfactory functional outcome. The complications in this series were preventable. Intrafocal pinning should be added to the surgical armamentarium in treating distal radius fractures.

Late disassembly of a modular acetabular component. A case report

Disassembly of metal-backed acetabular components used for total hip arthroplasty is becoming more common in both preassembled and modular designs. This complication is usually associated with a dislocation of the femoral component or other radiographic evidence of dissociation. A case of late disassembly of the acetabular component without dislocation or radiographic evidence is presented. The authors believe this complication should be considered, along with infection and aseptic loosening, in all cases of late development of pain following total hip arthroplasty.

Thigh pain after cementless hip arthroplasty. Annoyance or ill omen

A retrospective review of 148 consecutive porous-coated hip arthroplasties (PCA) showed an incidence of thigh pain of 13% one year after surgery, and 22% at two years. Positive correlations were made with femoral stem subsidence (greater than 2 mm) and with distal periosteal and endosteal bone formation. No positive correlations were made with parameters of bone quality or component fit. Resolution of pain occurred in one-third and an anti-inflammatory agent produced partial relief in two-thirds of the patients. We conclude that thigh pain is secondary to stem instability with distal stress transfer in the absence of stable proximal fixation.