High-resolution computed tomography analysis of the medial infratemporal fossa: a pilot study.

BACKGROUND: The medial aspect of the infratemporal fossa (ITF) can be accessed endoscopically. Two important landmarks to help guide dissection in this area have previously been identified: the anterior border of the foramen ovale (AFO) and the "bony bridge" (BB), a consistent bridge of bone between the foramen ovale and spinosum. We conducted a pilot study using high-resolution computed tomography (HRCT) to measure the distances to these structures. METHODS: Thirty measurements were acquired from 15 adult patients undergoing HRCT scans of the sinuses. The position of the anterior nasal spine (ANS), AFO, and BB on the 3 orthogonal planes were identified by 3 observers. Euclidian distances between each of these structures were calculated. A cadaveric dissection was performed and images were acquired to provide an endoscopic view. RESULTS: Fifteen HRCT scans of the sinuses (8 females) were analyzed. The mean distances from the ANS to the AFO and BB were 78.5 ± 5.9 mm and 83.2 ± 6.0 mm, respectively. For males alone, these distances were 80.3 ± 4.3 mm and 85.3 ± 4.8 mm, respectively, and in females 77.0 ± 6.5 mm and 81.4 ± 6.7 mm, respectively. CONCLUSION: Average distance from the ANS to the AFO and BB was 78.5 mm and 83.2 mm, respectively. These measurements can be used by endoscopic skull base surgeons to guide dissection in the ITF.

Molecular markers of micrometastasis in oral cavity carcinomas.

OBJECTIVE: To examine the expression of candidate markers for micrometastasis. STUDY DESIGN: Cross-sectional analysis of subjects with oral cavity carcinomas who underwent sentinel lymph node biopsy (SLNB) and subsequent immunohistochemical (IHC) analysis. SUBJECTS AND METHODS: Two groups were identified based on SLNB status: negative SLNB (19/30) and positive SLNB (11/30). Specimens underwent IHC using conjugated monoclonal antibodies for membrane type-1 matrix metalloproteinase (MT1-MMP), CD44, focal adhesion kinase-1, and E-cadherin. Staining results were evaluated to determine if a particular marker was associated with SLNB status or other histopathologic prognosticators. RESULTS: For MT1-MMP, 21 percent (3/14) of evaluable specimens stained positively in the SLNB(-) group and 67 percent (4/6) stained positively in the SLNB(+) group (P=0.12). No statistically significant association was seen between any marker's staining pattern and SLNB status alone. When MT1-MMP staining was evaluated in tumors with SLNB(+) or perineural invasion (PNI) present on histopathology, six of nine specimens (67%) stained positively for MT1-MMP, vs one of 11 (9%) in specimens lacking either negative prognosticator (P=0.016, RR=7.33). CONCLUSION: Preliminary results suggest that MT1-MMP positivity in primary tumor specimens may identify aggressive tumor types, evidenced by the presence of micrometastasis or PNI.

Endoscopic transnasal study of the infratemporal fossa: a new orientation.

INTRODUCTION: The medial portion of the infratemporal fossa (ITF) is not infrequently involved in sinonasal and skull base pathologies. However, endoscopic view of the ITF remains unclear with lack of studies addressing this region from the endoscopic perspective. METHODS: Using an extended endoscopic approach, the pterygopalatine and infratemporal fossae were dissected in 10 sides of five adult cadaver heads. A plane of dissection along the pterygoid base and the infratemporal surface of the greater sphenoid wing was developed. High-quality images were produced by coupling the video camera to a digital recording system. RESULTS: The foramen rotundum, ovale, and spinosum were accessed and new landmarks were described from the endoscopic point of view. The sphenomandibularis muscle was also highlighted. Maxillary and mandibular nerves and middle meningeal artery were all identified. Columellar measurements to the foramen rotundum and ovale ranged from 6.1 to 8.0 cm for the former and 7.0 to 9.1 cm for the latter, with a mean of 6.75 cm and 7.78 cm respectively. CONCLUSION: The current study provides a novel endoscopic orientation to the medial ITF. Such knowledge should provide an anatomical basis for experienced surgeons to endoscopically address this region with more safety and efficacy.

Endoscopic reconstruction of large anterior skull base defects using acellular dermal allograft.

BACKGROUND: Endoscopic repair of small- to medium-sized anterior skull base (ASB) defects using bone, cartilage, fascia, fibrin glue, lipolized dura, and, more recently, acellular dermal allograft have all been described with equal efficacy. The purpose of this study was to review our experience with the use of acellular dermis as the sole graft material in endoscopic reconstruction of large ASB defects. METHODS: A retrospective chart review of all patients who underwent endoscopic repair of ASB defects at the University of Miami between the years of 2001 and 2006 was conducted. Fifty-six patients were identified who met these criteria. All repairs were performed by a transnasal, endoscopic approach. Outcome measures included success of graft take and incidence of major and minor complications. Dural defect size was defined as small (<0.4 cm), intermediate (0.4-2.0 cm), and large (>2.0 cm). RESULTS: AlloDerm (AlloDerm. LifeCell Corp. Woodlands, TX) was used as the primary graft material in 30/55 (55%) cases; 16/55 (29%) of the repaired defects were classified as large. Graft success was 97% in the AlloDerm group and 92% in the non-AlloDerm group. The incidence of major and minor complications in the AlloDerm group was 0 and 3.3%, respectively. In the non-AlloDerm group, the incidence of major and minor complications was 4 and 12%, respectively. There were no statistical differences in the complication rates based on the type of repair or defect size. CONCLUSION: Alloderm can be used successfully to repair ASB defects, including large defects that are >2 cm in size with little or no morbidity.

Conservation of residual acoustic hearing after cochlear implantation.

OBJECTIVE: This study was designed to test the hypothesis that partial hearing conservation is attainable after cochlear implantation with a long perimodiolar electrode. Surgical strategies for hearing conservation during cochlear implantation are described. STUDY DESIGN: Prospective, single-subject, repeated-measures design. SETTING: Academic tertiary care center. PATIENTS: Twenty-eight severely to profoundly hearing-impaired adult cochlear implant recipients who had some measurable hearing preoperatively. INTERVENTION: Cochlear implantation using Nucleus Freedom Contour Advance electrode. MAIN OUTCOME MEASURES: Preimplant and postimplant pure-tone thresholds and speech recognition scores were obtained to determine the incidence and degree of conserved hearing at a mean interval of 9 (+/-3.9) months. RESULTS: Thirty-two percent of subjects experienced complete conservation of hearing (0- to 10-dB loss), and 57% experienced partial conservation of hearing (>11 dB) after implantation. However, open-set speech recognition was partially conserved in only one subject. Cochlear implant performance was not better in patients with conservation of residual hearing. CONCLUSION: Conservation of pure-tone hearing was possible in 89% of implanted patients; however, residual speech perception was not conserved with this long perimodiolar electrode. A ceiling effect tends to inflate the prevalence of hearing conservation in implantation studies of severely to profoundly hearing-impaired patients.