Search

Background. Preoperative vocal cord paralysis is a risk factor for postoperative respiratory distress following extubation after general anesthesia. We present an unusual case where a geriatric patient developed airway obstruction after robot-assisted laparoscopic prostatectomy. Case Presentation. A 67-year-old male, who had suffered from left vocal cord paralysis of unknown etiology, was scheduled for robot-assisted laparoscopic prostatectomy (RALP). General anesthesia was performed without any problems. The patient, however, developed airway obstruction one hour after extubation and was reintubated following commencement of mechanical ventilation for one day. At the age of 70 years, the patient received an emergency tracheostomy due to bilateral vocal cord paralysis and then was diagnosed with spinal and bulbar muscular atrophy (SBMA). Although no muscle weakness of either upper or lower extremities was observed, rocuronium showed hypersensitivity during total laryngectomy under general anesthesia. Conclusions. Vocal cord paralysis combined with postoperative laryngeal edema, the cause of which was presumed to be SBMA, likely caused airway obstruction after RALP. As neuromuscular symptoms progress gradually in patients with SBMA, muscle relaxants should be used carefully, even if patients with SBMA present no immobility of their extremities.

Volumetric modulated arc therapy (VMAT) is a rotational intensity-modulated radiotherapy (IMRT)technique capable of acquiring projection images for cone-beam computed tomography (CBCT). Respiratorycorrelatedcone-beam computed tomography, namely 4D-CBCT, serves to assess the displacement of a tumorposition between planning and treatment due to organ motion and respiration, and is important for more accurateradiation therapy. On the other hand, recently, a 320-detector row CT scanner, namely 4D-CT, hasbecome available that allows axial volumetric scanning of a 16-cm-long range in a patient without tablemovement. The goal of our research is to establish a new method of verification during treatment in stereotacticbody radiotherapy. In this study, we compare the movement of the tumor between “before treatment” using4D-CT and “in treatment” using 4D-CBCT. Three patients (55–68 years of age) with lung tumors underwentCT scans for radiotherapy planning using 4D-CT scans to analyze the movement of the tumor before treatment.The patients were treated by VMAT while acquiring projection images. 4D-CBCT datasets were reconstructedfrom the projection images using in-house programs. The tumor positions in 4D-CT and 4D-CBCTwere detected and the movement of the tumor between “before treatment” and “in treatment” was similar. Themovement of the tumors during treatment was predictable from 4D-CT before treatment. Furthermore,4D-CBCT clarified the tumor position during treatment and could reevaluate the actual tumor position anddose distribution. We have successfully shown the movement of the tumor between “before treatment” using4D-CT and “in treatment” using 4D-CBCT.

Multi-detector computed tomography (MDCT) has rapidly evolved and is increasingly used for treatment simulation of thoracic and abdominal radiotherapy. A 320-detector row CT scanner has recently become available that allows axial volumetric scanning of a 16-cm-long range in a patient without table movement. Current radiotherapy techniques require a generous margin around the presumed gross tumor volume (GTV) to account for uncertainties such as tumor motion and set up error. Motion analysis is useful to evaluate the internal margin of a moving target due to respiration and to improve therapeutic precision. The purpose of this study is to propose a method using phase-only correlation to automatically detect the target and to assess the motion of the target in numerical phantoms and patients. Free-breathing scans using 320-detector row CT were acquired for 4 patients with lung tumor(s). The proposed method was feasible for motion analysis of all numerical phantoms and patients. The results reproduced the facts that the motion of tumors in the patients varied in orbits during the respiratory cycle and exhibited hysteresis. The maximum distance between peak exhalation and inhalation increased as the tumors approached the diaphragm. The proposed method detected the three-dimensional position of the targets automatically and analyzed the trajectories. The tumor motion due to respiration differed by region and was greatest for the lower lobe.