Bone CT evaluation of nasal cavity of acromegalics--its morphological and surgical implication in comparison to non-acromegalics

Anatomical Differences in Sphenoid Sinus During Endoscopic Transsphenoidal Surgery: Comparison Between Nonfunctioning Pituitary Neuroendocrine Tumor (PiTNET) and Growth Hormone-Secreting PiTNET

BACKGROUND

In surgical practice during endoscopic endonasal approach, growth hormone-secreting pituitary neuroendocrine tumor (GH-secreting PitNET) patients show morphologic differences in the nasal cavities and sinuses, leading to a narrower surgical field and a carotid prominence and potentially increasing the complexity of the surgical and the risk of complications. The aim of the study is to evaluate the anatomical differences of the sphenoid sinus between patients with GH-secreting PitNETs and patients with nonfunctioning pituitary neuroendocrine tumor (NF-PitNET) who underwent endoscopic endonasal approach.

METHODS

This is a monocentric retrospective study conducted at the author's institution. The minimum intercarotid distance, the largest diameter of the sphenoid sinus (DSS), and the distance between vomer and clivus (VCD) were collected and compared. Presence, localization, and course of intersphenoid sinus septum were also evaluated.

RESULTS

One hundred consecutive patients were identified: 57 males (57%) and 43 females (43%), with a mean age of 55 years. Sixty patients had NF-PitNET (60%) and 40 had GH-secreting PitNET (40%). GH-secreting PitNET group presented inferior values of intercarotid distance (16.8 ± 3.94 mm vs. 20.4 ± 3.94 mm, P < 0.001), DSS (32.5 ± 9.81 mm vs. 38.6 ± 11.03 mm, P = 0.006), and VCD (25.5 ± 6.96 mm vs. 29.6 ± 8.47 mm, P = 0.012) compared to NF-PitNET group. Intersphenoid sinus septum showed no differences between the 2 groups.

CONCLUSIONS

Intercarotid distance, DSS, and VCD resulted smaller in acromegalic patients, confirming that patients with GH-secreting PitNETs have a narrower surgical field. A meticulous anatomical preoperative planning and neuronavigation are important to recognize the sphenoid anatomical landmarks in order to reduce the risk of complications, especially in acromegalic patients.

Vascular anomalies in patients with growth hormone-secreting pituitary adenomas: illustrative case report and systematic review of the literature

PURPOSE

Endonasal resection is the first-line treatment for patients harboring growth hormone (GH)-secreting pituitary adenomas. The complexity of the parasellar neurovascular structures makes pre-operative diagnostic imaging essential to understanding the anatomy of this region. We aimed to describe vascular anomalies in acromegalic patients and emphasize their relevance for surgery and preoperative planning.

METHODS

A systematic review following the PRISMA statement was performed in July 2021.

RESULTS

Thirty-three studies were evaluated. Elevated GH and insulin-like growth factor-1 (IGF-1) levels are linked to the occurrence of cardiovascular risk factors. This is attributed to endothelial dysfunction, mainly caused by changes in flow-mediated dilatation (FMD), which is probably the main cause of vascular anomalies in acromegaly. The occurrence of protrusions of the internal carotid artery (ICA) (35-53%), a narrow intercarotid distance, and an asymmetrical course was described. In 13-18% of acromegalic patients, the presence of an intracerebral aneurysm could be reported (incidence in the general population:0.8-1.3%). The selected studies were however performed with a small patient sample (range:1-257). We present a case report of a 57y/o male patient with anomalies of the ICA ("kissing carotid arteries") harboring a GH-secreting adenoma, which was resected via an endoscopic endonasal approach.

CONCLUSIONS

There is an association between acromegaly and endothelial dysfunction, which increases cardiovascular risk factors and vascular anomalies. Preoperative vascular imaging, e.g., CT angiography, should be implemented as a standard to identify patients at risk and estimate surgical morbidity. However, no evidence-based recommendations exist so far, so future studies are necessary.

Surgery for acromegaly: Indications and goals

Acromegaly is a disease that occurs secondary to high levels of GH, most often from a hormone-secreting pituitary adenoma, with multisystem adverse effects. Diagnosis includes serum GH and IGF-1 levels, and obtaining an MRI pituitary protocol to assess for a functional pituitary adenoma. Attempted gross total resection of the GH-secreting adenoma is the gold standard in treatment for patients with acromegaly for a goal of biochemical remission. Medical and radiation therapies are available when patients do not achieve biochemical cure after surgical therapy.

Morphometric Alterations of the Sphenoid Ostium and other Landmarks in Acromegaly: Anatomical Considerations and Implications in Endoscopic Pituitary Surgery

Background

The sphenoid ostium (SO) is an important landmark for the endoscopic surgeon. Changes in size and position of the SO and variations in other skull base landmarks in acromegalics have not been adequately evaluated.

Aims

The authors evaluated the morphometry and location of the SO and other landmarks in acromegaly and compared these findings with those in nonfunctioning pituitary adenomas (NFPAs).

Methods

In this retrospective case-control study, the dimensions and location of the SO and other skull base landmarks were radiologically evaluated in 18 patients with growth hormone (GH)-secreting adenomas. These findings were analyzed in relation to preoperative GH levels and compared with 18 age- and sex-matched controls with NFPAs.

Results

The dimensions of the SO were significantly larger in the GH-adenoma group (P < 0.05). The SO was further from the midline (P = 0.04) and closer to the sphenopalatine foramen (SPF) (P = 0.02) in the GH-adenoma group, and this finding correlated with increasing preoperative GH levels. Acromegalics demonstrated larger intracavernous carotid diameters (P = 0.05) and smaller intercarotid distances than the patients with NFPAs (P = 0.02).

Conclusion

The SO is larger and located higher up in the sphenoid face and closer to the SPF in patients with GH adenomas. Increasing GH levels in these patients correlate with the upward and lateral displacement of the SO. These patients demonstrate larger intracavernous carotid diameters and smaller intercarotid distances than patients with NFPAs. These morphological alterations are of particular relevance to the pituitary surgeon.

An advanced protocol for intraoperative visualization of sinunasal structures: experiences from pituitary surgery

OBJECTIVE

The transsphenoidal route to pituitary adenomas challenges surgeons because of the highly variable sinunasal anatomy. Orientation may be improved if the appropriate information is provided intraoperatively by image guidance. The authors developed an advanced image guidance protocol dedicated to sinunasal surgery that extracts information from multiple modalities and forms it into a single image that includes fine sinunasal structures and arteries.The aim of this study was to compare the advantages of this novel image guidance protocol with the authors' previous series, with emphasis on anatomical structures visualized and complication rate.

METHODS

This retrospective analysis comprised 200 patients who underwent surgery for pituitary adenoma via a transnasal transsphenoidal endoscopic approach. The authors' standard image guidance protocol consisting of CT for solid bone, T1CEMRI for soft tissues, and MRA for the carotid artery was applied in 100 consecutive cases. The advanced image guidance protocol added a first-hit ray casting of the CT scan for visualization of fine sinunasal structures, and adjustments to the MRA to visualize the sphenopalatine artery (SPA) were applied in a subsequent 100 consecutive cases.

RESULTS

A patent sphenoid ostium-i.e., an ostium not covered by a mucosal layer-was visualized significantly more often by the advanced protocol than the standard protocol (89% vs 40%, p < 0.001) in primary surgeries. The SPA and its branches were only visualized by the advanced protocol (87% and 91% of cases in primary surgeries and reoperations, respectively) and not once by the standard protocol. The number of visualized complete and incomplete sphenoid septations matched significantly more commonly with the surgical view when using the advanced protocol than the standard protocol at primary operation (mean 1.9 vs 1.6, p < 0.001). However, in 25% of all cases a complex and not a simple sinus anatomy was present. In comparison with the intraoperative results, a complex sphenoid sinus anatomy was always detected by the advanced but not by the standard protocol (25% vs 8.5%, p = 0.001).Furthermore, application of the advanced protocol reduced the cumulative rate of complications (25% vs 18% [standard vs advanced group]). Although an overall significant difference could not be determined (p = 0.228), a subgroup analysis of reoperations (35/200) revealed a significantly lower rate of complications in the advanced group (5% vs 30%, p = 0.028).

CONCLUSIONS

The data show that the advanced image guidance protocol could intraoperatively visualize the fine sinunasal sinus structures and small arteries with a high degree of detail. By improving intraoperative orientation, this may help to reduce the rate of complications in endoscopic transsphenoidal surgery, especially in reoperations.

Quantification of specific growth patterns and frequency of the empty sella phenomenon in growth hormone-secreting pituitary adenomas

PURPOSE

To assess and quantify the prevalence and co-occurence of a sellar floor lowering and empty sella phenomenon in patients with GH (growth hormone)-secreting pituitary adenoma.

METHODS

A total number of 159 acromegalic patients were included in this study, as well as two control groups (150 patients with non-GH-secreting adenomas and 50 patients without pituitary adenomas). Magnetic resonance images of all patients were evaluated for presence of an empty sella, downward and lateral tumor extension, and maximum superoinferior diameter of the mass. Additionally, these values were correlated with growth hormone and IGF-1 levels.

RESULTS

The empty sella phenomenon was detected significantly more often in patients with a GH-secreting adenoma with a prevalence of 22% vs. 5.3% in non-GH-secreting adenomas (p < 0.001) or 8% in the healthy control group (p = .036). Moreover, GH-secreting adenomas presented with a significant rate of downward tumor extension (74.8% vs. 35.5%; p < 0.001), whose extent correlated inversely but weakly with the GH hormone level (r = - 0.17; p = .036). It was also found that a decreased superoinferior diameter and higher ratio of intrasellar to suprasellar extension are predictive quantitative values for the presence of a GH-secreting adenoma (area under curve, 0.712).

CONCLUSIONS

GH-secreting pituitary adenomas are frequently associated with an empty sella phenomenon. Moreover, GH-secreting adenomas are frequently accompanied by an enhanced, quantitatively measurable impression of the sellar floor. Hypothetically, this is caused by tumor-induced local bone remodeling processes.

Anatomic Variations in Pituitary Endocrinopathies: Implications for the Surgical Corridor

Objectives/Hypotheses Functioning pituitary adenomas may produce endocrinopathies such as acromegaly and Cushing syndrome. Both conditions lead to characteristic anatomic variations as a result of hormonally induced abnormal soft tissue deposition. We evaluate the anatomic differences between acromegalics and Cushing disease patients and compare these dimensions to controls. Design Radiographic review of preoperative magnetic resonance images (MRI) of the pituitary gland. Setting Tertiary academic medical center. Participants Patients who underwent transnasal, transsphenoidal surgery for pituitary adenomas found to have acromegaly or pituitary Cushing between January 1, 2007 and September 1, 2015. A total of 15 patients with similar MRIs and no history of pituitary or sinonasal disease were selected as controls. Main Outcome Measures Dimensions assessed were intercarotid distance; carotid canal width; piriform aperture width; distance from the piriform aperture to the anterior face of the sphenoid; sphenoid sinus height, width, and length; angle from anterior nasal spine to anteroinferior face of sphenoid sinus; choanal height; and nasal cavity height at the level of the vertical segment of the middle turbinate. Sphenoid sinus pneumatization patterns were recorded. Results There were 30 acromegalics and 31 Cushing disease patients. When compared with controls, both acromegalics and Cushing disease patients had significantly wider piriform apertures and a longer distance from the piriform aperture to the anterior face of the sphenoid sinus (p < 0.05). Acromegalics had a significantly less acute angle (19 ± 3 degrees) from the anterior nasal spine to the sphenoid (p < 0.05). Cushing disease patients had significantly lower sphenoid sinus length and shorter nasal cavity height (p < 0.05). There were no differences in intercarotid distance or carotid canal width. Conclusions As acromegalics and Cushing disease patients have known anatomic variations, the skull base surgeon should be aware of these differences and adapt their techniques and approaches as needed.

Carotid artery protrusion and dehiscence in patients with acromegaly

PURPOSE

Acromegaly is a systemic disease which causes multiple bony alterations. Some authors reported that acromegalic patients have risk factors for an intraoperative vascular injury due to the specific anatomical features of their sphenoid sinus. The objective of our study was to analyze the anatomic characteristics of sphenoid sinus in acromegalic patients compared with controls, by evaluation of computed tomography (CT) findings.

METHODS

We examined 45 acromegalic (acromegaly group) and 45 non-acromegalic patients (control group) with pituitary adenomas who were matched for sex, age, height, tumor size, and cavernous sinus invasion (Knosp grade). Preoperative CT of the pituitary region including the sphenoid sinus was used to evaluate the following anatomic characteristics: type of sphenoid sinus (sellar or pre-sellar/conchal); intrasphenoid septa (non/single or multiple); carotid artery protrusion; carotid artery dehiscence; intercarotid distance.

RESULTS

Sixteen acromegalic patients (35.5 %) and 6 controls (13.3 %) had carotid artery protrusion. Additionally, 10 acromegalic patients (22.2 %) and 3 controls (6.6 %) had carotid artery dehiscence. Carotid artery protrusion and dehiscence were more frequent in the acromegaly group than in control group (p = 0.013 and 0.035, respectively). Other anatomic characteristics (type of sphenoid sinus, intrasphenoid septa, and intracarotid distance) showed no significant differences between acromegaly and control groups.

CONCLUSIONS

Our study suggests that carotid artery protrusion and dehiscence occur more frequently among acromegalic patients, compared with non-acromegalic patients. It is important for surgeons to be aware of these anatomic variations to avoid vital complications, such as carotid injuries, during surgery.

Fusiform dilatation of the cavernous carotid artery in acromegalic patients

BACKGROUND

Surgeons undertaking transsphenoidal surgery in patients with acromegaly confront multiple unique challenges secondary to the anatomic alterations caused by growth hormone-secreting tumors. The senior author has noted a fusiform dilatation of the cavernous carotid artery in many acromegalic patients. The authors aim to quantify this dilatation and correlate it with potential contributing factors.

METHODS

Clinical and radiographic data were retrospectively assessed in acromegalic patients undergoing transsphenoidal surgery from 2000 through 2011. Randomly selected patients with nonsecreting pituitary adenomas were used as the control cohort. Demographic information, comorbidities, and preoperative growth hormone and insulin-like growth factor-1 levels were recorded. Magnetic resonance (MR) imaging variables included tumor size, diameters of the petrous, cavernous, and supraclinoid segments of the carotid artery, and extent and location of cavernous sinus invasion. Independent correlations between acromegaly and each variable were assessed with multivariate regression analysis.

RESULTS

Forty randomly selected patients with growth hormone-secreting adenomas who underwent surgery and had MR imaging with thin coronal slices of the pituitary region were enlisted in our study cohort. The mean age was 45.7 years. Forty-two males (52.5 %) were included in the study. Mean carotid artery diameter measurements for acromegalic and control patients, respectively, were 4.2 vs. 3.8 mm (petrous carotid), 5.0 vs. 4.0 mm (cavernous carotid), and 3.3 vs. 2.9 mm (supraclinoid carotid). Multivariate analysis showed only age and cavernous carotid diameter were statistically significant independent variables (p = 0.02, p < 0.001, respectively). Age, tumor size, growth-hormone or insulin-like growth factor-1 levels, and cavernous sinus invasion did not correlate with cavernous carotid artery diameter.

CONCLUSIONS

In patients with acromegaly, there is a fusiform dilatation of the cavernous carotid artery that must be considered when planning transsphenoidal surgery.

Transphenoidal surgery in acromegalic patients: anatomical considerations and potential pitfalls

BACKGROUND

Transphenoidal surgery is an effective treatment for acromegalic patients with growth hormone (GH) producing pituitary adenomas. Since acromegaly is a systemic disease which causes multiple bony alterations, we hypothesized that it could affect the sphenoid sinus anatomy. The aim of the study was to determine whether acromegalic patients have sphenoid sinus alterations with potential surgical impact.

METHODS

Fourty-six consecutive patients (23 acromegalics-GH group, 23 non-acromegalics-nGH group) undergoing transphenoidal surgery were included in this study. Pre-operative volumetric CT scan of the head was used to assess the following anatomic characteristics: type of sphenoid sinus (sellar, pre-sellar, conchal); number of intrasphenoid septa; number of carotid-directed septa; intercarotid distance; depth of the sphenoid sinus; depth and size of the sella.

RESULTS

The sphenoid sinus was of the pre-sellar/conchal type in 26 % of the patients with acromegaly (n = 23) versus 9 % of the patients of the nGH group (n = 23). The number of intrasphenoid septations was significantly higher in the GH group than in the nGH group (P = .03). Interestingly, the intercarotid distance was smaller in GH patients than in nGH displaying a trend toward significance (P = .05). The sphenoid bone was deeper in the GH group as compared to the nGH group (P = .01) but the distance sphenoid sinus-sella was reduced (P < .01). Finally, the sella was not deeper, nor larger in acromegalic patients.

CONCLUSIONS

The sphenoid sinus of acromegalic patients resulted in being deeper, characterized by more septa and by a reduced intercarotid distance. These alterations deserve special pre- and intraoperative care, being potentially responsible for surgical difficulties.

Craniometric changes in patients with acromegaly from a surgical perspective

OBJECT

The objective of this study was to evaluate and analyze morphometric and volumetric changes of the skull due to acromegaly in areas relevant for neurosurgical practice, focusing on the surgical implications.

METHODS

On preoperatively acquired CT scans, cephalometric and volumetric measurements were performed on 45 patients with acromegaly (Group A) and 45 control patients (Group B). The authors determined thickness of the cranial vault, inner and outer diameters of the skull, and the diameter of sphenoidal and maxillary sinus, as well as frontal and maxillary sinus volumetry. The morphometric and volumetric CT data of the patients with acromegaly were compared with the data of a control group and correlated with clinical parameters.

RESULTS

Cranial vault thickness differed significantly (p < 0.0001) between the 2 groups. A correlation of the vault thickness with preoperative human growth hormone, insulin-like growth factor-I levels, and duration of clinical history in acromegaly could not be established. The outer anterior-posterior skull diameter of Group A (18.47 ± 0.94 cm) differed significantly (p = 0.0146) from Group B (17.98 ± 0.93 cm) and correlated significantly with preoperative human growth hormone (r = 0.3277; p = 0.0299) and insulin-like growth factor-–I serum levels (r = 0.3756; p = 0.0120). Measurements of the anterior-posterior diameter of the sphenoidal sinus differed significantly (p = 0.0074) between patients with acromegaly and controls. Volumetric analysis of the frontal sinus resulted in a statistically significant difference (p = 0.0382) between patients with acromegaly (14.89 ± 10.85 cm3) and controls (10.06 ± 6.93 cm3).

CONCLUSIONS

Significant craniometric changes and volumetric remodelling of the paranasal sinus occur in acromegaly. The bone alterations are of surgical importance for using the transsphenoidal approach. Detailed preoperative diagnostic examination and planning as well as selection of appropriate instruments are mandatory for safe and successful pituitary adenoma removal in patients with acromegaly.

Transsphenoidal surgery in patients with acromegaly: operative strategies for overcoming technically challenging anatomical variations

OBJECT

In addition to difficulties with anesthetic and medical management, transsphenoidal operations in patients with longstanding acromegaly are associated with inherent intraoperative challenges because of anatomical variations that occur frequently in these patients. The object of this study was to review the overall safety profile and anatomical/technical challenges associated with transsphenoidal surgery in patients with acromegaly.

METHODS

The authors performed a retrospective analysis of 169 patients who underwent endoscopic transsphenoidal operations for growth hormone-secreting adenomas to assess the incidence of surgical complications. A review of frequently occurring anatomical challenges and operative strategies employed during each phase of the operation to address these particular issues was performed.

RESULTS

Of 169 cases reviewed, there was no perioperative mortality. Internal carotid artery injury occurred in 1 patient (0.6%) with complex sinus anatomy, who remained neurologically intact following endovascular unilateral carotid artery occlusion. Other complications included: significant postoperative epistaxis (5 patients [3%]), transient diabetes insipidus (5 patients [3%]), delayed symptomatic hyponatremia (4 patients [2%]), CSF leak (2 patients [1%]), and pancreatitis (1 patient [0.6%]). Preoperative considerations in patients with acromegaly should include a cardiopulmonary evaluation and planning regarding intubation and other aspects of the anesthetic technique. During the nasal phase of the transsphenoidal operation, primary challenges include maintaining adequate visualization and hemostasis, which is frequently compromised by redundant, edematous nasal mucosa and bony hypertrophy of the septum and the nasal turbinates. During the sphenoid phase, adequate bony removal, optimization of working space, and correlation of imaging studies to intraoperative anatomy are major priorities. The sellar phase is frequently challenged by increased sellar floor thickness, distinct patterns of tumor extension and bony invasion, and anatomical variations in the caliber and course of the internal carotid artery. Specific operative techniques for addressing each of these intraoperative challenges are discussed.

CONCLUSIONS

Transsphenoidal surgery in patients with longstanding acromegaly frequently poses greater challenges than operations for other types of sellar lesions, yet these challenges may be safely and effectively overcome with the anticipation of specific issues and implementation of various intraoperative techniques.

Evaluation of pituitary macroadenomas with multidetector-row CT (MDCT): comparison with MR imaging

INTRODUCTION

It is important to have information on cavernous sinus extension and bony destruction in pituitary macroadenomas before surgery, but magnetic resonance (MR) imaging cannot always depict them. In the present study we sought to determine whether multidetector-row computed tomography (MDCT) could provide preoperative information in addition to that provided by MR imaging in pituitary macroadenoma.

METHODS

The subjects comprised 33 consecutive patients (15 women, 18 men; mean age 50 years) with surgically proven macroadenoma. For MDCT, using the soft-tissue window and bone window, three orthogonal multiplanar reconstruction images were generated from venous-phase contrast-enhanced 0.5-mm isotropic voxel data. MDCT and MR images were evaluated with regard to: (1) clarity of tumor margins; (2) identification of the normal pituitary gland; (3) identification of erosion or destruction of the sellar floor; and (4) visualization of the adjacent optic pathways.

RESULTS

MDCT more clearly demonstrated the lateral tumor margin than MR imaging (P = 0.002). No significant differences in visualization of the normal pituitary gland were noted between MDCT and dynamic MR imaging (P = 0.7). MDCT more clearly demonstrated sellar floor erosion or destruction at the sphenoid sinus than MR imaging (P < 0.001). MR imaging was superior to MDCT for visualizing the adjacent optic pathways (P < 0.001).

CONCLUSION

MDCT is superior to MR imaging for assessing lateral tumor margin and the sellar floor at the sphenoid sinus. MDCT offers useful preoperative information in addition to that obtained from MR imaging.