Chronic Morbidity of a Pilot Hole Burr Technique for Anterior Iliac Crest Autograft in Cervical Fusion.

Anterior cervical decompression and fusion is a commonly performed procedure for cervical pathology. Graft choices include autograft, allograft, xenograft, synthetic, or a combination. Autograft has been shown to increase fusion rate compared with allograft, yet high morbidity at the harvest site has been reported. Few studies have evaluated chronic graft site pain, and to the authors' knowledge, no study has evaluated morbidity of a pilot hole burr technique for anterior iliac crest harvest. The objective of this study was to evaluate chronic morbidity of anterior iliac crest harvest in anterior cervical decompression and fusion using a pilot hole burr technique. A phone survey was used to identify chronic morbidity. Number of levels fused, age, sex, and acute graft site complications were explored to evaluate impact of patient characteristics on chronic graft site pain. A total of 140 patients met inclusion criteria; 106 patients (76%) completed the phone survey. Mean follow-up was 38.9 months. Two patients (1.9%) reported current and constant graft site pain. Nine patients (8.5%) reported intermittent pain. Average numeric pain rating scale score for survey participants was 0.25 of 10. No patients were taking narcotics for graft site pain. Two patients (1.9%) reported functional impairment secondary to the graft site pain. There was no impact of number of levels fused, age, sex, or acute graft site complications on chronic graft site pain. The pilot hole burr technique resulted in low long-term morbidity and may offer an alternative to traditional methods for those wishing to use autologous graft in anterior cervical decompression and fusion. [Orthopedics. 2019; 42(1):e68-e73.].

Off-axis behavior of an infrared meander-line waveplate.

An infrared meander-line waveplate has been modeled and measured over the 8 to 12 microm spectral band in terms of its differential phase delay, axial ratio of the output polarization ellipse, and power throughput for angles of incidence between 0 degrees and 60 degrees. The study has been performed for planes of incidence parallel and perpendicular to the meander-line axis. The main significance is that the phase delay remains almost unaffected by the angle of incidence. Infrared meander-line retarders can thus be used well beyond the paraxial range as in low-f/# optical systems and in non-normal-incidence applications.

Demonstration of a single-layer meanderline phase retarder at infrared.

Meanderline wave plates are in common use at radio frequencies as polarization retarders. We present initial results of a gold meanderline structure on a silicon substrate that functions at a wavelength of 10.6 microm in the IR. The measured results show a distinct change in the polarization state of the incident beam after passing through the device, inducing a 74 degrees phase retardance between horizontal and vertical components. A high degree of polarization (88%) is maintained in the transmitted beam with an overall power transmittance of 38% and a beam profile that remains essentially unchanged.