Calculating nasoseptal flap dimensions: a cadaveric study using cone beam computed tomography

Nasoseptal flap with extended pedicle dissection based on the maxillary artery: Clinical series of 55 cases

KEY POINTS

Nasoseptal flap with extended pedicle dissection is a low morbidity and high success rate flap. It is a flap that can be applied to reconstruct a wide range of ipsilateral skull base defects.

Differences in the predicted nasoseptal flap length among races: A propensity score matching analysis

OBJECTIVES

We compared the lengths of a nasoseptal flap (NSF) and skull base according to race, age, and sex.

METHODS

We performed paranasal sinus computed tomography in 19,961 adult patients between 2003 and 2022. The race of the patients was East Asian (n = 71), Caucasian (n = 71), or Middle Eastern (n = 71). The expected lengths of the NSF and anterior skull base defect were measured and analyzed according to race, age, and sex.

RESULTS

Compared with Caucasians and Middle Easterners, East Asians had a shorter NSF length (p < 0.001) and lower ratio of the expected NSF length to the expected defect length (p < 0.001). There was no difference in the values among age groups. The expected NSF length was longer, and the ratio of the expected NSF length to the expected defect length was higher, in males than females (p < 0.001 for both).

CONCLUSIONS

East Asians and females had a shorter NSF length and lower ratio of expected NSF to surgical defect lengths after anterior skull base reconstruction compared with the other races and with males, respectively. Anatomical differences should be considered when long NSF lengths are required, such as for anterior skull base reconstruction.

Anterior skull base reconstruction using nasoseptal flap: cadaveric feasibility study and clinical implication [SevEN-001]

BACKGROUND

Pedicled nasoseptal flap (PNSF) has significantly improved the surgical outcomes of endoscopic endonasal approach (EEAs) by reducing cerebrospinal fluid (CSF) leakage. The purpose of this study is to assess the feasibility of using a PNSF for anterior skull base (ASB) reconstruction and to describe a method to compensate for a short flap based on our results.

METHODS

In this cadaveric study, ASB dissection without sphenoidotomy was performed using 10 formalin-fixed and 5 fresh adult cadaver specimens, and the sufficiency of the PNSF to cover the ASB was assessed. After the sphenoidotomy, the length by which the PNSF fell short in providing coverage at the posterior wall of the frontal sinus (CPFS), and the extent of the anterior coverage from the limbus (CL) of the sphenoid bone was measured.

RESULTS

Without sphenoidotomy, the mean length of the remaining PNSF after the coverage of the posterior wall of the frontal sinus was 0.67 cm. After sphenoidotomy, the PNSF fell short by a mean length of 2.10 cm, in providing CPFS. The CL was 1.86 cm. Based on these findings, defects resulting from an endoscopic resection of ASB tumors were reconstructed using PNSF without total sphenoidotomy in 3 patients. There were no postoperative CSF leaks or complications.

CONCLUSIONS

The use of PNSF for ASB reconstruction may be insufficient to cover the entire ASB defect after removal of large lesions which need total sphenoidotomy. When possible, by leaving some portion of the anterior sphenoid wall for supporting the PNSF, successful ASB reconstruction could be achieved in endoscopic resection of ASB tumors. Additional methods might be needed in some cases of large ASB lesions wherein the anterior sphenoid wall should be removed totally and the ASB defect is too large.

Anatomo-radiological study supporting the use of ipsilateral nasoseptal flap for the transpterygoid management of temporo-sphenoidal meningoceles. A review of 21 cases

OBJECTIVES

Surgical treatment of temporo-sphenoidal meningoceles involves the reduction of the meningocele, watertight closure and defect coverage with a nasoseptal flap (NSF). It can be performed contralaterally or ipsilaterally: in the latter situation, the pedicle of the flap must be dissected into the pterygopalatine fossa. The objective of this study was to evaluate the benefit of using an ipsilateral NSF in transpterygoid approaches for the management of temporo-sphenoidal meningoceles, compared to a contralateral NSF, based on a radiological study.

MATERIAL AND METHODS

Retrospective monocentric study of 21 cases, between 2002 and 2018. Measurement of the NSF lengths, and lengths needed to cover the defect were evaluated on the preoperative scanner. Early and later failure and complication rates were evaluated.

RESULTS

Seventeen cases of temporo-sphenoidal meningoceles with available CT scan were identified. The mean duration of follow up was 27.9 months [1-147]. Theoretical lengths of the ipsi and contralateral NSF were comparable: 71.4±7.8mm vs. 78.8±8mm, P=0.729. In 8 cases/18 (42%), the theoretical length of the contralateral NSF was not long enough to cover the defect beyond the V2 (mean lack of 8.87±6.6mm). In all cases, the theoretical length of the ipsilateral NSF was sufficient to cover the defect. In the case series, failure and complication rates were similar.

CONCLUSION

The use of an ipsilateral NSF for the transpterygoid management of temporo-sphenoidal meningoceles, although more complex, allows a better coverage of the defect, compared to the contralateral NSF, which is not long enough in 42% of cases.

Lengthening the nasoseptal flap pedicle with extended dissection into the pterygopalatine fossa

OBJECTIVES/HYPOTHESIS

Releasing the nasoseptal flap (NSF) pedicle from the sphenopalatine artery (SPA) foramen may considerably improve flap reach and surface area. Our objectives were quantify increases in pedicle length and NSF reach through extended pedicle dissection into the pterygopalatine fossa (PPF) through cadaveric dissections and present clinical applications.

STUDY DESIGN

Anatomical study and retrospective clinical cohort study.

METHODS

Twelve cadaveric dissections were performed. Following standard NSF harvest, the distance from the anterior edge of the flap to the anterior nasal spine while pulling the flap anteriorly was measured. As dissection into the SPA foramen and PPF continued, similar interval measurements were completed in four stages after release from the SPA foramen, release of the internal maxillary artery (IMAX), and transection of the descending palatine artery (DPA). The extended pedicle dissection technique was performed in seven consecutive patients for a variety of different pathologies.

RESULTS

The mean length of the NSF from the anterior nasal spine and maximum flap reach were 1.91 ± 0.40 cm/9.3 ± 0.39 cm following standard harvest, 2.52 ± 0.61 cm/9.75±1.06 cm following SPA foramen release, 4.93 ± 0.89 cm/12.16 ± 0.54 cm following full IMAX dissection, and 6.18 ± 0.68 cm/13.41 ± 0.75 cm following DPA transection. No flap dehiscence or necrosis was observed in all seven surgical patients.

CONCLUSIONS

Extended pedicle dissection of the NSF to the SPA/IMAX markedly improves the potential length and reach of the flap. This technique may provide a feasible option for reconstruction of large anterior skull base and craniocervical junction defects. Seven successful cases are presented here, but further studies with larger series are warranted to validate findings in a clinical setting.

LEVEL OF EVIDENCE

4 Laryngoscope, 130:18-24, 2020.

Three-dimensional evaluation of maxillary sinus volume in different age and sex groups using CBCT

AIM

Sinus maxillaris is an important anatomical formation in many branches of dentistry due to its proximity to the field of work. Various methods have been used in literature to measure the maxillary sinus volume (MSV) such as cadavers, stereology, two-dimensional conventional radiographs, computed tomography (CT), magnetic resonance imaging (MRI). The aim of this study is to evaluate the change of maxillary sinus volume according to age and gender with MIMICS 19.0 (Materialise HQ Technologielaan, Leuven, Belgium) which is one of three-dimensional modeling software.

MATERIALS AND METHODS

This study was performed in 200 patients selected by a retrospective review of the archives of the Dicle University, Faculty of Dentistry, Department of Oral and Maxillofacial Radiology. Patients were divided into five age groups (18-24 years, 25-34 years, 35-44 years, 45-54 years, and ≥ 55 years) and by sex. Cone-beam computed tomography (CBCT) images of the patients were transferred to the MIMICS software and the MSV was measured. All statistical analyses were performed using the SPSS (Statistical Package for Social Sciences, version 21) software.

RESULTS

There was no statistically significant difference between the right and left maxillary sinus volume according to the findings obtained from our study, and maxillary sinus volume in males was found to be significantly higher than that of females. Another finding of our study is that the maxillary sinus volume decreases with age increase. Especially it was also found that the sinus volume in males in the 18-24 age group was statistically significantly higher than females.

CONCLUSION

Consequently, maxillary sinus volume measurements can be made on CT, CBCT, MRI scans using reconstruction software.

The radioanatomy of endonasal flap coverage of skull base defects: A tool for preoperative planning

OBJECTIVES/HYPOTHESIS

To develop a tool for the calculation of surgical skull base defects and endonasal flap dimensions on preoperative computed tomography (CT) to aid surgical planning.

STUDY DESIGN

Case series.

METHODS

A literature search was conducted to identify all endonasal flaps. There were five basic models identified. These are the nasoseptal flap, anterior lateral nasal wall flap, bipedicled anterior septal flap, posterior pedicled inferior turbinate flap, and middle turbinate flap. Publications on the radioanatomy of endonasal flaps and surgical skull base defects were also identified. Using these descriptions as a reference, 38 radioanatomic variables were measured on CT scans obtained from 60 preoperative endonasal skull base surgery patients. These were then used to model endonasal flap coverage of six defects: transfrontal, transcribriform, transplanar, transsellar, transsphenoidal, and transclival.

RESULTS

The nasoseptal provides adequate coverage for most defects. The posteriorly pedicled inferior turbinate flap is a good alternative, and provides better coverage of posterior skull base defects. The anterior lateral nasal wall flap is the best choice for transfrontal defects. The middle turbinate flap and bipedicled anterior septal flaps provide secondary options when larger flaps are not available.

CONCLUSIONS

We have developed a simple tool for the calculation of endonasal flap coverage of surgical skull base defects on preoperative CT scans.

LEVEL OF EVIDENCE

4. Laryngoscope, 128:1287-1293, 2018.

Development of the Endoscopic Endonasal Sinus and Skull Base Surgery Questionnaire

BACKGROUND

The patients' perspective of health outcomes has become important input for assessing treatment effects. However, existing endoscopic endonasal surgery (EES) instruments are not fully aligned with the concept of health-related quality of life (HRQoL). A prospective cohort study was therefore conducted to develop a suitable quality-of-life tool to assess nasal morbidity after EES: the Endoscopic Endonasal Sinus and Skull Base Surgery Questionnaire (EES-Q).

METHODS

The study included 300 patients: 207 with sinus pathology and 93 with anterior skull base pathology. The EES-Q was administered prior to surgery and postoperatively (2 weeks, 3 months, and 1 year). Psychometric instrument properties were tested and relevant health domains were formulated. Seventy-two items were generated by the conventional psychometric approach. An exploratory factor analysis was used to test construct validity. The optimal number of factors to retain was determined by using the eigenvalues-greater-than-1 rule and scree plot. Orthogonal varimax rotation was used to enhance interpretability. Internal consistency was assessed using the Cronbach α.

RESULTS

The factor analysis yielded a 3-factor solution, representing physical, psychological, and social functioning. The final version of the instrument consisted of 30 items with a high internal consistency (>0.80) for all 3 HRQoL domains.

CONCLUSIONS

The EES-Q is a comprehensive, multidimensional, disease-specific instrument. A distinguishing characteristic is that, apart from the physical and psychological domains, the EES-Q also encompasses a social domain. Understanding different HRQoL aspects in patients undergoing EES may help caregivers restore, improve, or preserve the patient's health through individualized care, which depends on identifying their specific needs.