Image-guided endonasal transsphenoidal microsurgical treatment of recurrent microadenomas of the pituitary gland

Endoscopic Endonasal Trans-Sphenoidal Minimally Invasive Pituitary Surgery with Image Guided Navigation System (Igns): Learning Experience of Ent Surgeon: First Author

Introduction- Endoscopic minimally invasive pituitary surgery (MIPS) is advantageous over microscopic technique, as it provides superior close up, wide angle view of surgical target area. Image guided navigation system (IGNS) guides the surgeon to localize the lesion. In the present study we analyzed the Image Guided Surgical procedure and outcome of Endoscopic minimally invasive pituitary surgery and shared our experiences regarding disease clearance.

MATERIALS AND METHODS

During the period of April 2015 to August 2022 a total 104 patients, diagnosed with pituitary adenoma underwent surgery and further followed up in a multidisciplinary team approach in a tertiary care hospital of Kolkata, India. The data obtained were reviewed statistically to satisfy the study objectives.

RESULTS

Total 104 operations were done on 98 patients and total cases taken for calculation and analysis was 98, which consist of 11 microadenomas, 81 macroadenomas. Among 35 patients with normal preoperative hormonal assay, one patient developed postoperative hypopituitarism. Among 6 patients with preoperative hypopituitarism 4 patients (66.6%) recovered after surgery. Overall, 85 cases had total disease clearance as detected on post-operative MRI. In functioning pituitary adenoma (FPA) clinical and endocrinological improvement occurred after primary surgery in 85.36% (n = 35) and after revision surgery it was 84.44% (n = 38). Macroadenomas, giant adenomas were found to have statistically significant higher risk of incomplete disease clearance but large adenomas do not have statistically higher risk of incomplete clearance.

CONCLUSION

IGNS requires extra time for setup, but with proper registration of tracker instruments it adds precision to the surgery. IGNS supplements endoscopic visualization with localization of target lesion by real time stereotactic feedback using preset preoperative imaging data, thus increasing accuracy, safety and effectiveness of minimally invasive surgery.

Use of Neuronavigation and Augmented Reality in Transsphenoidal Pituitary Adenoma Surgery

The aim of this study was to report on the clinical experience with microscope-based augmented reality (AR) in transsphenoidal surgery compared to the classical microscope-based approach. AR support was established using the head-up displays of the operating microscope, with navigation based on fiducial-/surface- or automatic intraoperative computed tomography (iCT)-based registration. In a consecutive single surgeon series of 165 transsphenoidal procedures, 81 patients underwent surgery without AR support and 84 patients underwent surgery with AR support. AR was integrated straightforwardly within the workflow. ICT-based registration increased AR accuracy significantly (target registration error, TRE, 0.76 ± 0.33 mm) compared to the landmark-based approach (TRE 1.85 ± 1.02 mm). The application of low-dose iCT protocols led to a significant reduction in applied effective dosage being comparable to a single chest radiograph. No major vascular or neurological complications occurred. No difference in surgical time was seen, time to set-up patient registration prolonged intraoperative preparation time on average by twelve minutes (32.33 ± 13.35 vs. 44.13 ± 13.67 min), but seems justifiable by the fact that AR greatly and reliably facilitated surgical orientation and increased surgeon comfort and patient safety, not only in patients who had previous transsphenoidal surgery but also in cases with anatomical variants. Automatic intraoperative imaging-based registration is recommended.

Guidelines in the management of CNS tumors

INTRODUCTION

Evidence-based, clinical practice guidelines in the management of central nervous system tumors (CNS) continue to be developed and updated through the work of the Joint Section on Tumors of the Congress of Neurological Surgeons (CNS) and the American Association of Neurological Surgeons (AANS).

METHODS

The guidelines are created using the most current and clinically relevant evidence using systematic methodologies, which classify available data and provide recommendations for clinical practice.

CONCLUSION

This update summarizes the Tumor Section Guidelines developed over the last five years for non-functioning pituitary adenomas, low grade gliomas, vestibular schwannomas, and metastatic brain tumors.

Optimizing MR imaging for intraoperative image guidance in sellar pathologies

PURPOSE

With the advancement of extended endonasal approaches, the ability to surgically reach parasellar tumor extensions increase. The aim of the study was to propose an optimized imaging protocol for surgical guidance in the cavernous sinus (CS) for proper visualization structures at risk.

METHODS

Prospective case control analysis of 20 consecutive pituitary adenoma patients scheduled for endoscopic transnasal surgery. Assessment of the capability of three different MRI sequences (MPRAGE, VIBE, CISS) by 4 investigators to correctly visualize sellar and parasellar structures. Invasiveness and position of the normal pituitary gland were compared with the intraoperative findings.

RESULTS

The consensus between the 4 examiners to achieve the same results for all modalities was 40% for MPRAGE, 70% for VIBE and 60% for CISS sequences (p = 0.155). A consensus of Knosp Grade per patient was 80% for MPRAGE, 100% for VIBE and 90% for CISS (overall kappa 0.60). A higher Knosp Grade was found in MPRAGE sequences compared to the other sequences. Intraoperative status of invasiveness was correctly identified in 12/20 (60%) with MPRAGE, 19/20 (95%) with VIBE and 11/20 (55%) with CISS sequences. The position of the normal pituitary gland was most frequent evaluable in 15/20 (75%) and correctly identified in 12/15 (80%) cases.

CONCLUSION

Our data showed that VIBE sequences obtain the highest degree of consensus with intraoperative findings of invasiveness and position of the normal pituitary gland. VIBE sequences, due to their high spatial resolution and at the same time fast image acquisition could provide improved imaging for neuronavigation.

An advanced navigation protocol for endoscopic transsphenoidal surgery

OBJECTIVE

To report our clinical experience with an advanced navigation protocol that provides seamless integration into the operating workflow of endoscopic transsphenoidal surgery.

PATIENTS AND METHODS

From 32 consecutive cases of endoscopic transsphenoidal surgery, an optimal setup of continuous electromagnetic instrument navigation was created. Additionally, our standard multimodality image navigation of T1-weighted magnetic resonance (MR) images for soft tissue, MR angiogram for vascular structures, and computed tomography (CT) for solid bone was advanced by the addition of a CT surface rendering for fine paranasal sinus structures. The anatomic structures visualized and their clinical impacts were compared between standard and advanced visualization protocol. Bone-windowed CT images served as reference. The accuracy of the navigation setup was assessed by intraoperative landmark tests. Potential tissue shift was calculated by comparing pre- and postoperative MR angiograms of 20 macroadenomas.

RESULTS

After a learning curve of 2 cases (1 ferromagnetic interference and 1 dislocation of the patient reference tracker), the advanced navigation protocol was feasible in 30 cases. Advanced multimodality imaging was able to visualize significantly finer paranasal sinus structures than multimodality image navigation without CT surface rendering, equal to bone-windowed CT images (P < 0.001, McNemar test). This was found helpful for orientation in cases of complex sphenoid sinus anatomy. The accuracy of the advanced navigation setup corresponded to standard optic navigation with skull fixation. A tissue shift of median 2 mm (range 0-9 mm) was observed in the posterior genu of the internal carotid arteries after tumor resection.

CONCLUSIONS

The advanced navigation protocol permits continuous suction-tracked navigation guidance during endoscopic transsphenoidal surgery and optimal visualization of solid bone, fine paranasal sinus structures, soft-tissue and vascular structures. This may add to the safety of the procedure especially in cases of anatomical variations and in cases of recurrent adenomas with distorted anatomy.

Endoscopic endonasal transsphenoidal approach for resection of a coexistent pituitary macroadenoma and a tuberculum sellae meningioma

The coexistence of a pituitary macroadenoma and a tuberculum sellae meningioma is very rare. This article demonstrates the surgical technique of the simultaneous resection of a pituitary macroadenoma and a tuberculum sellae meningioma using an endoscopic, endonasal, biportal, transsphenoidal approach. A 36-year-old woman presented with frontal headache and extended visual field loss of the right eye. She underwent cranial magnetic resonance imaging (MRI) revealing a 2 × 2 × 2.5 mm contrast-enhancing intrasellar and suprasellar lesion with compression of the optic chiasma. The coexistence of a pituitary macroadenoma and meningioma was suggested. A biportal endoscopic endonasal transsphenoidal approach was performed to remove both lesions. The histological results confirmed the coexistence of the pituitary macroadenoma and meningioma, World Health Organization (WHO) grade I. The endoscopic, endonasal, transsphenoidal approach is a safe and reliable minimal invasive surgical alternative for resection of the intra-, supra- and parasellar lesions, avoiding additional craniotomy.

Use of Tissue Glues in Endoscopic Pituitary Surgery: A Cost Comparison

Background:

Post-operative cerebrospinal fluid (CSF) leaks are a common complication of endoscopic pituitary surgery and account for a significant proportion of hospital costs associated with this procedure. Tisseel® is a tissue glue commonly used as an adjunct in dural repair but is not optimal for this purpose. DuraSeal® has several properties advantageous for dural repair but is not widely accepted in Canada partly due to its increased cost.

Objective:

A cost analysis of DuraSeal® versus Tisseel® in endoscopic pituitary surgery.

Methods:

A cost analysis was performed based on typical endoscopic pituitary surgery cases performed at our tertiary care institution. Operating room, hospital admission, and surgical sealant costs were obtained directly while estimates of patient recovery time and post-operative CSF leak rates were based on consensus values reported in the literature. Outcomes were reported for various possible clinical scenarios of sealant use.

Results:

In a model where surgical sealant is employed only in high-risk cases, use of DuraSeal® allows for a yearly cost savings of at least $4486.72. If surgical sealant is used in all cases, regular use of DuraSeal® versus Tisseel® either marginally reduces yearly costs or increases them by a maximum of $7619.25, depending on the case volume and estimated post-operative CSF leak rate.

Conclusion:

In most clinical scenarios, use of DuraSeal® in endoscopic pituitary surgery may reduce overall yearly hospital costs compared to Tisseel®.

Application of image guidance in pituitary surgery

Background:

Surgical treatment of pituitary pathologies has evolved along the years, adding safety and decreasing morbidity related to the procedure. Advances in the field of radiology, coupled with stereotactic technology and computer modeling, have culminated in the contemporary and widespread use of image guidance systems, as we know them today. Image guidance navigation has become a frequently used technology that provides continuous three-dimensional information for the accurate performance of neurosurgical procedures. We present a discussion about the application of image guidance in pituitary surgeries.

Methods:

Major indications for image guidance neuronavigation application in pituitary surgery are presented and demonstrated with illustrative cases. Limitations of this technology are also presented.

Results:

Patients presenting a history of previous transsphenoidal surgeries, anatomical variances of the sphenoid sinus, tumors with a close relation to the internal carotid arteries, and extrasellar tumors are the most important indications for image guidance in pituitary surgeries. The high cost of the equipment, increased time of surgery due to setup time, and registration and the need of specific training for the operating room personnel could be pointed as limitations of this technology.

Conclusion:

Intraoperative image guidance systems provide real-time images, increasing surgical accuracy and enabling safe, minimally invasive interventions. However, the use of intraoperative navigation is not a replacement for surgical experience and a systematic knowledge of regional anatomy. It must be recognized as a tool by which the neurosurgeon can reduce the risk associated with surgical approach and treatment of pituitary pathologies.

TRANSSPHENOIDAL PITUITARY MACROADENOMAS RESECTION GUIDED BY POLESTAR N20 LOW-FIELD INTRAOPERATIVE MAGNETIC RESONANCE IMAGING

OBJECTIVE

To evaluate the applicability of low-field intraoperative magnetic resonance imaging (iMRI) during transsphenoidal surgery of pituitary macroadenomas.

METHODS

Fifty-five transsphenoidal surgeries were performed for macroadenomas (modified Hardy's Grade II–IV) resections. All of the surgical processes were guided by real-time updated contrast T1-weighted coronal and sagittal images, which were acquired with 0.15 Tesla PoleStar N20 iMRI (Medtronic Navigation, Louisville, CO). The definitive benefits as well as major drawbacks of low-field iMRI in transsphenoidal surgery were assessed with respect to intraoperative imaging, tumor resection control, comparison with early postoperative high-field magnetic resonance imaging, and follow-up outcomes.

RESULTS

Intraoperative imaging revealed residual tumor and guided extended tumor resection in 17 of 55 cases. As a result, the percentage of gross total removal of macroadenomas increased from 58.2% to 83.6%. The accuracy of imaging evaluation of low-field iMRI was 81.8%, compared with early postoperative high-field MRI (Correlation coefficient, 0.677; P &lt;0.001). A significantly lower accuracy was identified with low-field iMRI in 6 cases with cavernous sinus invasion (33.3%) in contrast to the 87.8% found with other sites (Fisher's exact test, P &lt;0.001).

CONCLUSION

The PoleStar N20 low-field iMRI navigation system is a promising tool for safe, minimally invasive, endonasal, transsphenoidal pituitary macroadenomas resection. It enables neurosurgeons to control the extent of tumor resection, particularly for suprasellar tumors, ensuring surgical accuracy and safety, and leading to a decreased likelihood of repeat surgeries. However, this technology is still not satisfying in estimating the amount of the parasellar residual tumor invading into cavernous sinus, given the false or uncertain images generated by low-field iMRI in this region, which are difficult to discriminate between tumor remnant and blood within the venous sinus.