Relaxing Sphenoidal Slit Incision to Extend the Anterior and Posterior Reach of Pedicled Nasoseptal Flaps During Endoscopic Skull Base Reconstruction of Transcribriform Defects: Technical Note and Results in 20 Patients

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.

Skull base repair following endonasal pituitary and skull base tumour resection: a systematic review

PURPOSE

Postoperative cerebrospinal fluid rhinorrhoea (CSFR) remains a frequent complication of endonasal approaches to pituitary and skull base tumours. Watertight skull base reconstruction is important in preventing CSFR. We sought to systematically review the current literature of available skull base repair techniques.

METHODS

Pubmed and Embase databases were searched for studies (2000-2020) that (a) reported on the endonasal resection of pituitary and skull base tumours, (b) focussed on skull base repair techniques and/or postoperative CSFR risk factors, and (c) included CSFR data. Roles, advantages and disadvantages of each repair method were detailed. Random-effects meta-analyses were performed where possible.

RESULTS

193 studies were included. Repair methods were categorised based on function and anatomical level. There was absolute heterogeneity in repair methods used, with no independent studies sharing the same repair protocol. Techniques most commonly used for low CSFR risk cases were fat grafts, fascia lata grafts and synthetic grafts. For cases with higher CSFR risk, multilayer regimes were utilized with vascularized flaps, gasket sealing and lumbar drains. Lumbar drain use for high CSFR risk cases was supported by a randomised study (Oxford CEBM: Grade B recommendation), but otherwise there was limited high-level evidence. Pooled CSFR incidence by approach was 3.7% (CI 3-4.5%) for transsphenoidal, 9% (CI 7.2-11.3%) for expanded endonasal, and 5.3% (CI 3.4-7%) for studies describing both. Further meaningful meta-analyses of repair methods were not performed due to significant repair protocol heterogeneity.

CONCLUSIONS

Modern reconstructive protocols are heterogeneous and there is limited evidence to suggest the optimal repair technique after pituitary and skull base tumour resection. Further studies are needed to guide practice.

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.

Efficacy of simultaneous pericranial and nasoseptal "double flap" reconstruction of anterior skull base defects after combined transbasal and endoscopic endonasal approaches

BACKGROUND

The "double flap" reconstruction technique, comprised of a simultaneous vascularized pedicled pericranial flap (PCF) and pedicled nasoseptal flap (NSF), can be used to repair anterior skull base defects after a combined cranionasal or transbasal-endoscopic endonasal approach (EEA) has been performed to remove malignant anterior skull base tumors. The use of two vascularized flaps may potentially decrease the incidence of post-radiation flap necrosis and postoperative cerebrospinal fluid (CSF) leaks after radiation therapy.

METHODS

We conducted a retrospective review of a prospective skull base database on patients who underwent the double flap reconstruction technique after a combined transbasal-EEA approach. Data collected for each patient included demographics, method of tumor resection and repair, complications, tumor recurrence, and follow-up.

RESULTS

Nine patients who underwent a combined transbasal-EEA approach for resection of anterior skull base tumors with significant intracranial extension followed by reconstruction of the cranial base using the double flap technique. Four were men and five were women, with a mean age of 49 years (range, 15-68 years). There was no postoperative CSF leakage detected or complications of infection, meningitis, mucocele, or tension pneumocephalus after a mean follow-up of 35.7 months (range, 4.5-98 months). Seven of the nine patients underwent adjuvant radiation without flap necrosis. Local tumor recurrence was not observed in any of the patients at last follow-up; however, one patient developed distant brain metastasis.

CONCLUSION

The simultaneous PCF and NSF double flap reconstruction is an effective technique in preventing postoperative CSF leakage and post-radiation necrosis when repairing anterior skull base defects after combined transbasal-EEA approaches. This technique may be useful in patients anticipated to undergo postoperative radiation therapy.

Update on anterior skull base reconstruction

PURPOSE OF REVIEW

Anterior skull base reconstruction has rapidly evolved over the past few years as endoscopic approaches to resect tumors in this region have become more established. The present review evaluates the robust amount of new literature on this topic over the past year with particular attention to minimally invasive methods for reconstruction.

RECENT FINDINGS

Although vascularized local flaps remain the mainstay reconstructive choice when available for the anterior skull base, innovative techniques for all types of reconstruction, ranging from free grafts to free flaps continue to emerge.

SUMMARY

Because of the unique challenges and wide variety of options available to repair the anterior skull base with the goal to prevent or treat cerebrospinal fluid leaks, surgical expertise and experience in this field is of utmost importance.

Repair of Anterior Skull Base Defect by Dual-Layer/Split-Frontal Pericranial Flap

INTRODUCTION

Normal skull base structures are destroyed either by the skull base pathology itself or during surgery that results in cerebrospinal fluid (CSF) leak. Skull base repair is usually performed transnasally by using a nasal septal flap. But when NSF is not available and failed repeated transnasal repair, a cranionasal repair with frontal pericranial flap (PF) can be attempted to achieve the highest successful chance. We performed a dual layer/split PF repair of a skull base defect using cranionasal approach and here we describe the technique.

CASE DESCRIPTION

A 74-year-old man suffered from CSF leak and ventriculitis after multiple transnasal surgeries for pituitary macroadenoma despite multiple repairs with intranasal vascularized flaps. We performed repair by cranionasal approach and using frontal PF. The frontal PF was divided into left and right halves. The left half went intradural, through the chiasmatic window to reach the sella and cover the tubercular and sellar defect from above. The right half went through the nasion into the nose to cover the defect from below. So the defect was covered by two vascularized flap from a single frontal PF. The repair was successful with no CSF leak and infection successfully treated by antibiotics.

CONCLUSION

We introduced the cranionasal dual layer/split PF technique to repair anterior skull base and successfully stopped the CSF leak in a patient after multiple EEA surgeries. This technique should only be considered in specific difficult situation where usual repair by EEA is impossible.

Clinical outcomes in male patients with lactotroph adenomas who required pituitary surgery: a retrospective single center study

PURPOSE

Lactotroph adenomas (LA) are the most frequently encountered pituitary tumors. Although more frequently observed in women, LAs in men were recently included in a more aggressive category regardless of histological grading, by the WHO. We aimed to perform a rigorous retrospective review of a single center's pre-operative evaluation, patient characteristics and outcomes of male LAs patients requiring pituitary surgery.

METHODS

A retrospective review, over 11 years, of patients who underwent resection of a pituitary adenoma at a single center was conducted. Predictors of persistent disease in male LAs patients along with a comparison to predictors of silent corticotroph adenomas (SCAs) patients who also underwent surgery at the center was also conducted.

RESULTS

Thirty-one male patients with LAs were identified. When compared to SCAs patients, LAs male patients were younger (41 vs. 50 years of age, p = 0.01). Men with LAs had more invasive tumors (75% vs. 44.7% p = 0.02). More LAs in men had residual tumor after surgery than patients with SCA (92.6% vs. 42.1%, p < 0.001). Male patients with LAs and patients with SCA had similar rates of requiring additional surgery (28.9% vs. 24.1%, p = NS) and radiation therapy (18.4% vs. 19.4%, p = NS).

CONCLUSIONS

High rates of DA resistance, invasive tumors and postoperative residual disease in male patients with LA who required surgery are shown. Surgery improved optic chiasm compression, PRL level and central hypogonadism but, not surprisingly, failed to normalize other pituitary hormones and/or eliminate need for DA therapy.