2025 Poster Presentations
P348: BEYOND TRADITIONAL BOUNDARIES: A SKULL BASE MORPHOMETRIC CADAVERIC STUDY OF THE NOVEL CONTRALATERAL NASOFRONTAL TREPHINATION APPROACH TO THE LATERAL RECESS OF THE SPHENOID SINUS
Guilherme Mansur, MD1; Moataz D Abouammo, MD, MSc1; Mohammad B Alsavaf, MD1; Chandrima Biswas, MD1; Rodrigo Gehrke, MD1; Claudio Callejas, MD1; Maithrea S Narayanan, MBBS, MMED2; Guilherme Finger, MD, MSc1; Kyle Wu, MD1; Kathleen Kelly, MD1; Ricardo L Carrau, MD1; Daniel M Prevedello, MD1; 1The Ohio State University; 2Hospital Kuala Lumpur
Background: The lateral recess (LR) of the sphenoid, defined as the most lateral extension of this sinus, is a pneumatized cavity that extends beyond a line drawn from the foramen rotundum to the vidian canal. Notably, the LR is not a constant anatomical feature, as its presence depends on the degree of pneumatization of the sphenoid sinus. Conditions affecting the LR, including cerebrospinal fluid (CSF) leaks, encephaloceles, chronic sphenoid sinusitis, mucoceles, and various neoplasms, often necessitate surgical intervention. Traditional endoscopic endonasal approaches like the transpterygoid approach (TPA) are commonly employed but can involve significant morbidity due to extensive dissection and manipulation of critical structures. This study introduces and evaluates the feasibility, anatomical aspects, and limitations of a novel Contralateral Nasofrontal Trephination (CNT) technique, aimed at reducing morbidity and improving surgical outcomes.
Methods: Twenty fresh cadaveric specimens (25 LRs due to asymmetrical pneumatization) were dissected. Each specimen underwent bilateral spheno-ethmoidectomies with full exposure to the LR of the sphenoid. The vidian canal was exposed and the vidian nerve was preserved. Subsequently, a nasofrontal incision and trephination were performed on the contralateral side. Draf 2b was then performed connecting it to the sinonasal tract. Quantitative measures of the area of exposure (AoE) and volume of surgical freedom (VSF) were obtained for each port, and statistical analyses were performed using the Shapiro-Wilk test and paired t-tests, with a significance level of 5%. Additionally, we provide an illustrative case where the CNT approach was successfully applied to treat a meningoencephalocele within the LR.
Results: The descriptive statistics revealed an AoE of 314.03 ± 40.74 mm² for the CNT approach and 276.27 ± 40.76 mm² for the endoscopic endonasal approach (EEA). The VSF for the EEA was 2191.39 ± 23.75 cc, whereas the VSF for the CNT approach was 1664.32 ± 65.15 cc. The Shapiro-Wilk test confirmed normal distribution of variables. Paired t-tests showed that the CNT approach provided a significantly larger AoE (t = 10.478, p < 0.001, mean difference = 37.759 mm²) compared to the EEA. Conversely, the EEA provided a greater VSF (t = 42.568, p < 0.001, mean difference = 527.071 cc).
Conclusion: The CNT approach offers advantages over the traditional TPA. By avoiding extensive dissection near the Vidian Canal and pterygopalatine fossa, the CNT approach mitigates the risk of complications such as hypoesthesia, dry eye, and other sensory deficits. This method also preserves the integrity of the orbital contents, reducing the risks when compared to approaches that require transorbital corridors. The CNT can be combined with endonasal corridors to enhance surgical access and maneuverability. This dual-port strategy, using the CNT for either the endoscope or instruments while utilizing the nostrils for additional instruments or the endoscope, maximizes the advantages of both approaches. The reduced VSF may impact the CNT's suitability for more complex surgical procedures requiring extensive dissection. Despite this, for focal pathologies such as bone defects associated with CSF leaks and encephaloceles, the CNT approach offers good maneuverability, as demonstrated in our illustrative case.
