Resection of the medial wall of the cavernous sinus in functioning pituitary adenomas: Technical note and outcomes in a matched-cohort study

Clinical and therapeutic implications of cavernous sinus invasion in pituitary adenomas

Invasion of the cavernous sinus by pituitary adenomas impedes complete surgical resection, compromises biochemical remission, and increases the risk of further tumor recurrence. Accurate preoperative MRI-based diagnosis or intraoperative direct inspection of cavernous sinus invasion are essential for optimal surgical planning and for tailoring postoperative therapeutic strategies, depending on whether a total resection has been achieved, or tumoral tissue has been left in surgically inaccessible locations. The molecular mechanisms underlying the invasive behavior of pituitary adenomas remain poorly understood, hindering the development of targeted therapies. Some studies have identified genes overexpressed in pituitary adenomas invading the cavernous sinus, offering insights into the acquisition of invasive behavior. Their main limitation however lies in comparing purely intrasellar specimens obtained from invasive and non-invasive adenomas. Further, precise anatomical knowledge of the medial wall of the cavernous sinus is crucial for grasping the mechanisms of invasion. Recently, alongside the standard intrasellar surgery, extended endoscopic intracavernous surgical procedures with systematic selective resection of the medial wall of the cavernous sinus have shown promising results for invasive secreting pituitary adenomas. The first- and second-generation somatostatin agonist ligands and cabergoline are used with variable efficacy to control secretory activity and/or growth of intracavernous remnants. Tumor regrowth usually requires surgical reintervention, sometimes combined with radiotherapy or radiosurgery which is applied despite their benign nature. Unraveling the molecular pathways driving invasive behavior of pituitary adenomas and their tropism to the cavernous sinuses is the key for developing efficient innovative treatment modalities that could reduce the need for repeated surgery or radiotherapy.

Efficacy and safety of cavernous sinus medial wall resection in pituitary adenoma surgery: a systematic review and a single-arm meta-analysis

INTRODUCTION

Pituitary adenomas, benign tumors, can lower quality of life. Pituitary adenomas that invade the medial wall and cavernous sinus (CS) indicate tumor recurrence and partial surgical excision. Despite the cavernous sinus's complexity and risks, new research has improved the surgical procedure and made excision safer. This comprehensive review and single-arm meta-analysis evaluates endocrinological remission and resection rates in pituitary adenomas to determine the benefits and risks of MWCS resection.

METHODS

Databases were systematically searched for studies documenting the resection of the medial wall of the cavernous sinus. The primary outcome was endocrinological remission in patients who underwent resection of the MWCS.

RESULTS

Eight studies were included in the final analysis. The pooled proportion of endocrinological remission (ER) was 63.3%. The excision of MWCS pooled a gross total resection (GTR) proportion of 72.9%. Finally, ICA injury attained a pooled ratio of 0.5%, indicating minimal morbidity in the procedure.

CONCLUSION

The cavernous sinus was ruled out, proving the MWCS excision is safe. Limiting population selection to Knosp 3A or lower enhanced GTR frequencies and lowered recurrence, according to subgroup analyses. This meta-analysis shows that MWCS resection can be a beneficial treatment option for pituitary tumors, when there is no macroscopic medial wall invasion and careful patient selection is done, especially for GH- and ACTH-producing tumors that can cause life-threatening metabolic changes.

Endoscopic Endonasal Resection of the Medial Wall of the Cavernous Sinus and Its Impact on Outcomes of Pituitary Surgery: A Systematic Review and Meta-Analysis

Introduction. Pituitary adenomas have the potential to infiltrate the dura mater, skull, and the venous sinuses. Tumor extension into the cavernous sinus is often observed in pituitary adenomas and techniques and results of surgery in this region are vastly discussed in the literature. Infiltration of parasellar dura and its impact for pituitary surgery outcomes is significantly less studied but recent studies have suggested a role of endoscopic resection of the medial wall of the cavernous sinus, in selected cases. In this study, we discuss the techniques and outcomes of recently proposed techniques for selective resection of the medial wall of the cavernous sinus in endoscopic pituitary surgery. Methods. We performed a systematic review of the literature using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and protocol and a total of 4 studies with 106 patients that underwent an endoscopic approach for resection of pituitary tumors with resection of medial wall from cavernous sinus were included. Clinical and radiological data were extracted (sex, mean age, Knosp, prior surgery, tumor size and type, complication rate, and remission) and a meta-analysis using the RevMan 5.4 software was performed. Results. A total of 5 studies with 208 patients were included in this analysis. The mean age of the study population was 48.87 years (range 25−82) with a female/male ratio of 1:1.36. Majority of the patients had Knosp Grade 1 (n = 77, 37.02%) and Grade 2 (n = 53, 25.48%). The complication rate was 4.81% (n = 33/106) and the most common complication observed was a new transient CN dysfunction and diplopia. Early disease remission was observed in 94.69% of the patients (n = 196/207). The prevalence rate of CS medial wall invasion varied from 10.4 % up to 36.7%. This invasion rate increased in frequency with higher Knosp Grade. The forest plot of persistent disease vs. remission in this surgery approach showed a p < 0.00001 and heterogeneity (I^2 = 0%). Discussion. Techniques to achieve resection of the medial wall of the cavernous sinus via the endoscopic endonasal approach include the “anterior to posterior” technique (opening of the anterior wall of the cavernous sinus) and the “medial to lateral” technique (opening of the inferior intercavernous sinus and). Although potentially related with improved endocrinological outcomes, these are advanced surgical techniques and require extensive anatomical knowledge and extensive surgical experience. Furthermore, to avoid procedure complications, extensive study of the patient’s configuration of cavernous ICA, Doppler-guided intraoperative imaging, surgical navigation system, and blunt tip knives to dissect the ICA’s plane are recommended. Conclusion. Endoscopic resection of the medial wall of the cavernous sinus has been associated with reports of high rates of postoperative hormonal control in functioning pituitary adenomas. However, it represents a more complex approach and requires advanced experience in endoscopic skull base surgery. Additional studies addressing case selection and studies evaluating long term results of this technique are still necessary.

The endonasal midline inferior intercavernous approach to the cavernous sinus: technical note, cadaveric step-by-step illustration, and case presentation

PURPOSE

Traditional endoscopic endonasal approaches to the cavernous sinus (CS) open the anterior CS wall just medial to the internal carotid artery (ICA), posing risk of vascular injury. This work describes a potentially safer midline sellar entry point for accessing the CS utilizing its connection with the inferior intercavernous sinus (IICS) when anatomically present.

METHODS

The technique for the midline intercavernous dural access is described and depicted with cadaveric dissections and a clinical case.

RESULTS

An endoscopic endonasal approach exposed the periosteal dural layer of anterior sella and CS. The IICS was opened sharply in midline through its periosteal layer. The feather knife was inserted and advanced laterally within the IICS toward the anterior CS wall, thereby gradually incising the periosteal layer of the IICS. The knife was turned superiorly then inferiorly in a vertical direction to open the anterior CS wall. This provided excellent access to the CS compartments, maintained the meningeal layer of the IICS and the medial CS wall, and avoided an initial dural incision immediately adjacent to the ICA.

CONCLUSION

The midline intercavernous dural access to the CS assisted by a 90° dissector-blade is an effective modification to previously described techniques, with potentially lower risk to the ICA.

The medial wall and medial compartment of the cavernous sinus: an anatomic study using plastinated histological sections

The medial wall of the cavernous sinus (CS) has a significant role in evaluation and treatment of pituitary adenomas. This study was conducted to clarify the fine architecture of the medial wall and medial compartment of the CS at both macro- and micro-levels in twenty-one human cadaveric heads by using the epoxy sheet plastination technique. The sellar part medial wall is an intact dural layer that separates the CS from the pituitary gland. This dural wall adhered to the diaphragma sellae and the periosteum of the sella turcica to form fibrous triangles. Eight micro-protrusions of the pituitary gland were found at both sides of that wall. The thickness of the sellar part medial wall at its central portion was significantly thinner than that at the other surrounding portions. From the superior view, tortuous intracavernous carotid arteries can be divided into outward bending type and inward bending type. The inward bending intracavernous carotid was apt to bent towards the central part of the sellar part medial wall, where there were usually wide and short fibrous bands with more densely stained connective tissues between them. The micro-protrusion of the pituitary gland in the medial wall of the CS could provide an anatomical basis for the occult tumor invasion and the recurrence of residual tumor. Different bending facing states of tortuous intracavernous carotid arteries in the lateral direction may be a factor of the determination of the direction of growth of pituitary tumors.

Expression and clinical significance of Cathepsin K and MMPs in invasive non-functioning pituitary adenomas

Background

Cathepsin K (CTSK) is a protease that degrades type I collagen and extracellular matrix, thereby contributing to bone resorption and tumor invasion. Some pituitary adenomas (PAs) could invade the sphenoid sinus (SS) and cavernous sinus (CS).

Purpose

This retrospective cohort study aimed to study the expression of tumoral biomarkers (CTSK, MMP9, MMP2, TIMP2, and PTTG1) and evaluate their clinical significance in non-functioning pituitary adenomas (NFPAs) with different invasion patterns.

Methods

We assessed the expression levels of candidate invasion-specific protein biomarkers CTSK, MMP9, MMP2, TIMP2, and PTTG1 by immunohistochemical staining in paraffin-embedded NFPA tumor tissues. Variations in staining intensity were analyzed in cases with SS and CS invasion and non-invasive NFPAs.

Results

We found that the levels of CTSK were higher in PA cases with SS invasion than that in PA cases with CS invasion (95.57 ± 31.57 vs. 65.29 ± 29.64, P < 0.001), and the expression of MMP9 and MMP2 was higher in CS-invasive cases than that in SS-invasive cases (145.02 ± 49.25 vs. 111.80 ± 51.37, P = 0.002, and 138.67 ± 52.06 vs. 108.30 ± 41.70, P = 0.002). Multiple Cox regression demonstrated that higher CTSK expression (P=0.011), subtotal resection (P<0.001), invasion (P=0.037), and larger tumor diameter (P=0.001) were independent risk factors for recurrence. A positive correlation was observed between CTSK expression and tumor size (r=0.671, p<0.001). There was no significant difference in TIMP2 and PTTG1 levels between CS-and SS-invasive cases (97.42± 39.80 vs. 102.10± 43.22, P = 0.58 and 13.89 ± 4.59 vs. 12.56 ± 3.96, P = 0.14).

Conclusion

Our data indicated that CTSK has the potential as a marker for SS invasion of PAs, whereas MMP9 and MMP2 may be markers for CS invasion. And CTSK may play an important role in tumor relapse.

Advances in Pituitary Surgery

Pituitary surgery has advanced considerably in recent years with the exploration and development of various endoscopic approaches and techniques. Different endoscopic skull base approaches are being applied to access sellar tumors in different locations. Moreover, extracapsular dissection and cavernous sinus exploration have enabled gross total resection of sellar tumors where it could not have been achieved in the past. Techniques for skull base reconstruction have also progressed, allowing surgeons to remove larger and more complicated tumors than before. This review article discusses different endoscopic skull base approaches, surgical techniques for removing pituitary adenomas, and reconstruction methods for repairing postoperative low-flow and high-flow cerebrospinal fluid leakage.

Pretreating cavernous sinus with hemostatic agent injection molding during endoscopic endonasal pituitary surgery: technical note

OBJECTIVE

To clarify the technical pearls of cavernous sinus molding technique with hemostatic agent injection during endoscopic endonasal pituitary surgery.

METHODS

All patients pretreated with cavernous sinus hemostatic agent injection molding technique for hemostasis in endoscopic endonasal surgery for pituitary adenoma resection between November 2017 and June 2021 were included. A small incision was made in the cavernous sinus wall before intracavernous manipulation. The hemostatic agent was injected with gentle pressure. It spread along the venous channels and established partial molding of the cavernous sinus. Intraoperative bleeding, surgical field score, and complications were evaluated.

RESULTS

Thirty-eight patients with pituitary adenoma requiring cavernous sinus manipulation were pretreated with this technique. Technically, the tailored thin blunt metal tube with its 1 cm head end bended up 45° were the best instrument to accomplish injection. Multi-spot injections were preferred to control different compartments of the cavernous sinus, which both had a better effect in bleeding control and helped to reduce the influence of trigemino-cardiac reflex. Postoperative complications, including temporal lobe edema, hemorrhage, and exophthalmos were not observed.

CONCLUSION

Pretreating cavernous sinus with hemostatic agent injection molding technique during endoscopic endonasal pituitary surgery is a practical, effective and safe method for intracavernous bleeding control.

Prognostic Factors for Recurrence in Pituitary Adenomas: Recent Progress and Future Directions

Pituitary adenomas (PAs) are benign lesions; nonetheless, some PAs exhibit aggressive behaviors, which lead to recurrence. The impact of pituitary dysfunction, invasion-related risks, and other complications considerably affect the quality of life of patients with recurrent PAs. Reliable prognostic factors are needed for recurrent PAs but require confirmation. This review summarizes research progress on two aspects—namely, the clinical and biological factors (biomarkers) for recurrent PAs. Postoperative residue, age, immunohistological subtypes, invasion, tumor size, hormone levels, and postoperative radiotherapy can predict the risk of recurrence in patients with PAs. Additionally, biomarkers such as Ki-67, p53, cadherin, pituitary tumor transforming gene, matrix metalloproteinase-9, epidermal growth factor receptor, fascin actin-bundling protein 1, cyclooxygenase-2, and some miRNAs and lncRNAs may be utilized as valuable tools for predicting PA recurrence. As no single marker can independently predict PA recurrence, we introduce an array of comprehensive models and grading methods, including multiple prognostic factors, to predict the prognosis of PAs, which have shown good effectiveness and would be beneficial for predicting PA recurrence.