Self-expanding metal stent insertion by colorectal surgeons using a two-person approach colonoscopy without fluoroscopic monitoring in the management of acute colorectal obstruction: a 14-year experience.

BACKGROUND: Placement of a self-expanding metal stent (SEMS) in patients presenting with an acute colorectal obstruction (ACO) may obviate emergency surgery (ES), potentially effectively palliating incurable tumors, acting as a bridge to surgery (BTS) in patients with operable or potentially operable tumors and achieving effective decompression of other ACO. We present our experience with SEMS insertion by colorectal surgeons without fluoroscopic monitoring for ACO especially for acute malignant colorectal obstruction (AMCO) for nearly a 14-year period (2007-2020). AIM: To explore the safety and effectiveness of SEMS insertion in the management of ACO by colorectal surgeons using a two-person approach colonoscopy without fluoroscopic monitoring. METHODS: We reviewed the medical records of patients retrospectively to identify all patients presenting to our unit with ACO especially with AMCO who had stenting carried out to achieve colonic decompression. All 434 procedures were performed by colorectal surgeons using a two-person approach colonoscopy without fluoroscopic monitoring. RESULTS: The overall technique success rate and clinic success rate by SEMS insertion were 428/434 (98.6%) and 412/434 (94.9%). The overall incidence of complications by SEMS insertion was 19/434 (4.4%). The complications included clinical perforation (6/434, 1.4%); stent migration (2/434, 0.5%), 1 of which re-stent; stent detachment (fell off) (3/434, 0.7%), none of them with re-stent; stool impaction (6/434, 1.4%), 1 of which re-stent; and abdominal or anal pain (2/434, 0.5%). There was no hemorrhage in any of the 434 patients. CONCLUSIONS: SEMS insertion is a relatively safe and effective technique for colonic decompression in dealing with ACO as either a BTS or as a palliative measure. It is also a solution to other causes of ACO such as recurrent tumor, benign diseases, or extra-luminal compression. Therefore, ES was largely avoided.

Extracting the phase information from atomic memory by intensity correlation measurement.

We demonstrate experimentally controlled storage and retrieval of the optical phase information in a higher-order interference scheme based on Raman process in (87)Rb atomic vapor cells. An interference pattern is observed in intensity correlation measurement between the write Stokes field and the delayed read Stokes field as the phase of the Raman write field is scanned. This result implies that the phase information of the Raman write field can be written into the atomic spin wave via Raman process in a high gain regime and subsequently read out via a spin-wave enhanced Raman process, thus achieving optical storage of phase information. This technique should find applications in optical phase image storage, holography and information processing.

Observation of coherence between two independent atomic ensembles by Raman scattering.

By using spontaneous Raman processes in the high-gain regime, we create instantaneous coherence between two independent atomic ensembles. The coherence is confirmed by the observation of temporal beating between the two subsequent readout fields converted from the atomic excitations through another enhanced Raman process. The beat frequency is found to be a result of an AC Stark frequency shift effect. We find that, due to the spontaneous nature of the process, the phases of the two ensembles change from one realization to another even though there is good coherence for a single realization.

Observation of the Rabi oscillation of light driven by an atomic spin wave.

Coherent conversion between a Raman pump field and its Stokes field is observed in a Raman process with a strong atomic spin wave initially prepared by another Raman process operated in the stimulated emission regime. The oscillatory behavior resembles the Rabi oscillation in atomic population in a two-level atomic system driven by a strong light field. The Rabi-like oscillation frequency is found to be related to the strength of the prebuilt atomic spin wave. High conversion efficiency of 40% from the Raman pump field to the Stokes field is recorded and it is independent of the input Raman pump field. This process can act as a photon frequency multiplexer and may find wide applications in quantum information science.