Literature Review: A Roundup of Important Recent Studies

Study design: Fresh cadaveric specimen dissection.

Setting: Robotic Skills Laboratory, The Ohio State University Wexner Medical Center, Columbus.

Synopsis: A fresh cadaveric specimen was dissected at the center’s Robotic Skills Laboratory. The laboratory environment was designed to be similar to that of a standard operating room. To facilitate the transnasal-transoral approach, researchers performed a posterior septectomy, enabling the transnasal introduction of an 8-mm 0° robotic camera. A transoral corridor provided access to the hard palate. For the transpalatal approach, a U-shaped mucosal incision was performed 5 mm medial to the maxillary dentition of the hard palate. Adjunctive transcervical ports allowed robotic instrument introduction directed cranially toward the clivus. A 1.5-cm incision allowed the manual introduction of the ports. Various combinations of camera corridors and EndoWrist instrument were reviewed. The transoral camera (30°) and instruments provided good control of the posterior and lateral nasopharynx; however, they did not provide adequate access over the roof of the nasopharynx or posterior choana. The transnasal camera (0°) and trans-

oral instruments provided excellent visualization, but instrumentation was cumbersome. Neither EEA nor TORS solved the problem of drilling the skull base.

Bottom line: In combined use, EEA and TORS provide excellent exposure of the posterior skull base, nasopharynx and infratemporal fossa.

Citation: Ozer E, Durmus K, Carrau RL, et al. Applications of transoral, transcervical, transnasal, and transpalatal corridors for robotic surgery of the skull base. Laryngoscope. 2013;123:2176-2179.

—Reviewed by Amy Eckner

Cartilaginous Tissue Regeneration with Bioengineered Trachea

Is a bioengineered trachea effective in the rapid regeneration of the trachea in pediatric patients?

Background: Many times, surgical treatment including tracheal or laryngotracheal reconstruction is required for tracheal or subglottic stenosis management to avoid suffocation or dyspnea. For tracheal reconstruction, Teramachi and Nakamura and colleagues developed a tracheal prosthesis with polypropylene mesh and rings as a frame and collagen sponge as a scaffold. Because the frame does not expand, however, only adult cases have benefited.

Study design: Prospective controlled trial in an animal model.

Setting: Fukushima Medical University, Fukushima City, Japan.

Synopsis: A bioengineered trachea composed of autologous chondrocytes was developed, and its effect on cartilaginous regeneration was evaluated by surgical implantation into tracheal defects in 12-week-old male Japanese white rabbits. A tracheal prosthesis without chondrocytes was implanted in a control group. At two weeks after implantation, cartilaginous tissue formation was not clearly observed in the bioengineered group with H&E staining, but Alcian blue staining revealed regenerated cartilaginous tissue at the defect; in the control group, no cartilaginous tissue was observed in the tracheal prosthesis or at the edge of the tracheal cartilage. At eight weeks, regenerated cartilaginous tissue was observed in the bioengineered trachea, and the tracheal cartilage defect had been repaired into a ring-shaped form as a whole; in the control group, no regenerated cartilaginous tissue was observed in the tracheal prosthesis. At 14 weeks, more regenerated cartilaginous tissue was apparent in the bioengineered trachea, and the defect repair was maintained in the ring-shaped form as a whole.