Transmastoid extradural-intracranial approach for repair of transtemporal meningoencephalocele: a review of 31 consecutive cases.

OBJECTIVE: To review the clinical presentation, surgical techniques, and outcomes of the transmastoid extradural-intracranial (TMEDIC) approach for the treatment of transtemporal meningoencephalocele. HYPOTHESIS: The TMEDIC is a safe and effective approach to repair meningoencephalocele originating from the middle or posterior cranial fossa. STUDY DESIGN: Retrospective chart review. SETTING: Academic neurotologic tertiary referral center. PATIENTS: Thirty-one consecutive patients diagnosed with transpetrous meningo(encephalo)cele, with or without cerebrospinal fluid leak, between January of 2003 and October of 2010. INTERVENTION: TMEDIC approach for repairing herniated neural tissue through the tegmen or posterior fossa plate using the combination of autologous cartilage, fascia, and tissue sealant. MAIN OUTCOME MEASURES: Anatomic location, size, and number of defects, presence of herniated brain tissue, pre- and postoperative hearing thresholds, and failure rate. RESULTS: Mean age was 62 ± 26 years. The etiology was spontaneous in 25/31 (80%), congenital in 3/31 (10%), chronic otitis media in 2/31 (6%), and posttraumatic in 1/31 (4%). Posttympanostomy tube clear otorrhea was the presenting sign in 21/31 (68%) of patients. The mean duration of symptoms was 26 months (range: 1-240). The defect involved the middle fossa (MF) floor in 25/31 (90%). Both the tegmen tympani and mastoideum were involved in 12/31 (39%) of patients and multiple dehiscences were seen in 7/31 (22%). In 17/31 (55%) of cases the size exceeded 1 cm. No recurrences were seen. CONCLUSION: The TMEDIC is a safe and effective method to repair transtemporal meningoencephalocele obviating the need for a middle fossa craniotomy in certain cases.

Scaffold-free tissue-engineered cartilage implants for laryngotracheal reconstruction.

OBJECTIVES/HYPOTHESIS: Donor site morbidity, including pneumothorax, can be a considerable problem when harvesting cartilage grafts for laryngotracheal reconstruction (LTR). Tissue engineered cartilage may offer a solution to this problem. This study investigated the feasibility of using autologous chondrocytes to tissue-engineer scaffold-free cartilage grafts for LTR in rabbits to avoid degradation that often arises from an inflammatory reaction to scaffold carrier matrix. STUDY DESIGN: Animal study. METHODS: Auricular cartilage was harvested from seven New Zealand white rabbits, the chondrocytes expanded and loaded onto a custom-made bioreactor for 7 to 8 weeks to fabricate autologous scaffold-free cartilage sheets. The sheets were cut to size and used for LTR, and the rabbits were sacrificed 4, 8, and 12 weeks after the LTR and prepared for histology. RESULTS: None of the seven rabbits showed signs of respiratory distress. A smooth, noninflammatory scar was visible intraluminally; the remainder of the tracheal lumen was unremarkable. Histologically, the grafts showed no signs of degradation or inflammatory reaction, were covered with mucosal epithelium, but did show signs of mechanical failure at the implantation site. CONCLUSIONS: These results show that autologous chondrocytes can be used to fabricate an implantable sheet of cartilage that retains a cartilage phenotype, becomes integrated, and does not produce a significant inflammatory reaction. These findings suggest that with the design of stronger implants, these implants can be successfully used as a graft for LTR.

Tissue-engineered trachea for airway reconstruction.

OBJECTIVES/HYPOTHESIS: Scaffold-free cartilage has been used to engineer biocompatible and mechanically stable neotracheas in vivo. The purpose of this animal study was to determine if neotracheal constructs, implanted paratracheally, could successfully be used for segmental tracheal reconstruction. STUDY DESIGN: Animal study. METHODS: Culture-expanded auricular rabbit chondrocytes were used to engineer scaffold-free cartilage sheets. Cartilage and a strap muscle flap were wrapped around a tube and implanted paratracheally. At 12 to 14 weeks postimplantation neotracheas were used to reconstruct 20 mm tracheal defects. Surgical technique was modified several times in an attempt to decrease the amount of neotracheal obstruction and fibrosis. In one of the six rabbits, neotrachea with its intact strap muscle flap was dropped into the defect followed by an end-to-end anastomosis; in two animals the muscle flap was partially, and in one rabbit completely removed. In two animals the muscle flap was partially removed, the tube reinserted, and the construct reimplanted for 5 weeks to allow formation of a fibrous lining over the exposed cartilage followed by tracheal reconstruction. RESULTS: All implants developed into vascularized and mechanically sound neotracheas. Following reconstruction, none of the animals showed immediate signs of respiratory distress; however, one died after 24 hours due to extensive endotracheal muscle flap edema, whereas rabbits who had undergone partial or complete muscle flap removal survived up to 39 days before developing cicatricial stenosis. CONCLUSIONS: Tissue-engineered neotracheas proved to have excellent biocompatibility and stability to function under physiologic conditions, but lacked adequate endotracheal lining resulting in neotracheal stenosis.