Usefulness of N-vinyl-2-pyrrolidone Embalming for Endoscopic Transnasal Skull Base Approach in Cadaver Dissection

Abstract

Formalin or formaldehyde is commonly used for cadaver fixation, which is, however, not suitable for endoscopic transnasal skull base approach because of consequent hardening of the soft tissue. Several alternatives have been reported, but each of them also has some limitations. We applied a novel fixation method using N-vinyl-2-pyrrolidone (NVP), a precursor of the water-soluble macromolecular polymer, for endoscopic transnasal skull base approach in six donated cadaver specimens. In four cadavers, elasticity of the soft tissue in the nasal cavity was almost similar to that of living tissue, and a surgical approach similar to the real surgical field was possible. However, the soft tissue was moderately stiffer than living tissue in two specimens so that surgical manipulation was hindered to some extent while NVP concentration was 10% in all the cadavers. Since the brain tissue was too soft and pliable for surgical manipulation in NVP, more careful surgical manipulation than real surgical field was mandatory in order to prevent damage in the brain tissue. Therefore, this concentration of NVP was considered to be appropriate. In conclusion, NVP embalming was effective for endoscopic transnasal skull base approach in cadaver dissection, providing environment similar to the real surgical field.

Preparation of Soft Embalmed Cadavers by the Modified Thiel Embalming Technique for Surgical Skill Training and Development of a Universal Quantitative Scoring System to Assess the Suitability of Soft Embalmed Cadavers for Such Training Purposes

“…The better flexibility of a soft embalmed cadaver can help in the better detection of tissue planes during dissection [11]. Nowadays, a new embalming technique using N-vinyl-2-pyrrolidone has been used in cadaver dissection to teach procedures such as endoscopic transnasal skull base approach, laparoscopic training, endotracheal intubation, and motion physiology of vocal folds [8,12,13].…”

Innovative Cadaver Preservation Techniques: a Systematic Review

“…The "preserve" solution, which included 100% NVP and 0.1% N,N'-dibutyl-phenylenediamine, was diluted to provide NVP concentrations of 10% of body weight. The arteries were ligated once the infusion was finished, and the corpse was submerged in 5 L of 5% "Preserve" solution in a sealed plastic bag and preserved at 4°C (27). The endoscopic transnasal skull base approach was reported to be successful in cadaver dissection that had been embalmed with NVP, providing an atmosphere that was similar to something like a realistic surgical field (27).…”

“…The arteries were ligated once the infusion was finished, and the corpse was submerged in 5 L of 5% "Preserve" solution in a sealed plastic bag and preserved at 4°C (27). The endoscopic transnasal skull base approach was reported to be successful in cadaver dissection that had been embalmed with NVP, providing an atmosphere that was similar to something like a realistic surgical field (27). Another research revealed that cadavers fixed with NVP exhibited more range of motion than those preserved with formalin.…”

“…N-vinyl-2-pyrrolidone has a number of disadvantages. With increasing NVP concentration, flexibility decreased, and even at the maximum concentration of 20%, the brain tissue was too soft to dissect (27).…”

Workable Cadaveric Preservation for Developing Skills Training Models: A Review

“…The cadaver fixation for approaching norma basalis by endoscopic transnasal route was tested by utilizing a "preserve "solution (table:1) [52]. The cadavers were observed to have soft, pliable body cavities, transparent connective tissue with reduced subcutaneous fat, clearly delineated vessels, nerves and flexible joints.…”