Intra-operative MRI facilitates tumour resection during trans-sphenoidal surgery for pituitary adenomas

Health Care Disparities in Transsphenoidal Surgery for Pituitary Tumors: An Experience from Neighboring Urban Public and Private Hospitals

Objectives  Few studies have assessed the role of socioeconomic health care disparities in skull base pathologies. We compared the clinical history and outcomes of pituitary tumors at private and public hospitals to delineate whether health care disparities exist in pituitary tumor surgery. Methods  We reviewed the records of patients who underwent transsphenoidal pituitary tumor resection at NYU Langone Health and Bellevue Hospital. Seventy-two consecutive patients were identified from each hospital. The primary outcome was time-to-surgery from initial recommendation. Secondary outcomes included postoperative diabetes insipidus, cerebrospinal fluid (CSF) leak, and gross total resection. Results  Of 144 patients, 23 (32%) public hospital patients and 24 (33%) private hospital patients had functional adenomas ( p  = 0.29). Mean ages for public and private hospital patients were 46.5 and 51.1 years, respectively ( p  = 0.06). Private hospital patients more often identified as white ( p  < 0.001), spoke English ( p  < 0.001), and had private insurance ( p  < 0.001). The average time-to-surgery for public and private hospital patients were 46.2 and 34.8 days, respectively ( p  = 0.39). No statistically significant differences were found in symptom duration, tumor size, reoperation, CSF leak, or postoperative length of stay; however, public hospital patients more frequently required emergency surgery ( p  = 0.03), developed transient diabetes insipidus ( p  = 0.02), and underwent subtotal resection ( p  = 0.04). Conclusion  Significant socioeconomic differences exist among patients undergoing pituitary surgery at our institution's hospitals. Public hospital patients more often required emergency surgery, developed diabetes insipidus, and underwent subtotal tumor resection. Identifying these differences is an imperative initial step in improving the care of our patients.

The Knosp Criteria Revisited: 3-Dimensional Volumetric Analysis as a Predictive Tool for Extent of Resection in Complex Endoscopic Pituitary Surgery

BACKGROUND

The Knosp criteria have been the historical standard for predicting cavernous sinus invasion, and therefore extent of surgical resection, of pituitary macroadenomas. Few studies have sought to reappraise the utility of this tool after recent advances in visualization and modeling of tumors in complex endoscopic surgery.

OBJECTIVE

To evaluate our proposed alternative method, using 3-dimensional (3D) volumetric imaging, and whether it can better predict extent of resection in nonfunctional pituitary adenomas.

METHODS

Patients who underwent endoscopic transsphenoidal resection of pituitary macroadenomas at our institution were reviewed. Information was collected on neurological, endocrine, and visual function. Volumetric segmentation was performed using 3D Slicer software. Relationship of tumor volume, clinical features, and Knosp grade on extent of resection was examined.

RESULTS

One hundred forty patients were identified who had transsphenoidal resection of nonfunctional pituitary adenomas. Macroadenomas had a median volume of 6 cm 3 (IQR 3.4-8.7), and 17% had a unilateral Knosp grade of at least 3B. On multiple logistic regression, only smaller log-transformed preoperative tumor volume was independently associated with increased odds of gross total resection (GTR; odds ratio: 0.27, 95% CI: 0.07-0.89, P < .05) when controlling for tumor proliferative status, age, and sex (area under the curve 0.67). The Knosp criteria did not independently predict GTR in this cohort ( P > .05, area under the curve 0.46).

CONCLUSION

Increasing use of volumetric 3D imaging may better anticipate extent of resection compared with the Knosp grade metric and may have a greater positive predictive value for GTR. More research is needed to validate these findings and implement them using automated methods.

Impact of Intraoperative Magnetic Resonance Imaging on Short-Term and Long-Term Outcomes After Transsphenoidal Resection of Pituitary Adenoma: A Systematic Review and Meta-Analysis

BACKGROUND

Intraoperative magnetic resonance imaging (iMRI) allows for greater tumor visualization and extent of resection. It is increasingly used in transsphenoidal surgeries but its role is not yet established.

OBJECTIVE

We aimed to clarify the usefulness of iMRI in transsphenoidal surgery using direct statistical comparisons, with additional subgroup and regression analyses to investigate which patients benefit the most from iMRI use.

METHODS

Systematic searches of PubMed, Embase, and Cochrane Central were undertaken from database inception to May 2020 for published studies reporting the outcomes of iMRI use in transsphenoidal resection of pituitary adenoma.

RESULTS

Thirty-three studies reporting 2106 transsphenoidal surgeries in 2099 patients were included. Of these surgeries, 1487 (70.6%) were for nonfunctioning pituitary adenomas, whereas 619 (29.4%) were for functioning adenomas. Pooled gross total resection (GTR) was 47.6% without iMRI and 66.8% with iMRI (risk ratio [RR], 1.32; P < 0.001). Subgroup and meta-regression analyses demonstrated comparable increases in GTR between microscopic (RR, 1.35; P < 0.001) and endoscopic (RR, 1.31; P < 0.001) approaches as well as functioning and nonfunctioning adenomas (P = 0.584). The pooled rate of hypersecretion normalization was 73.0% within 3 months and 51.7% beyond 3 months postoperatively. The pooled rate of short-term and long-term improvement in visual symptoms was 96.5% and 84.9%, respectively. The incidence of postoperative surgical complications was low. The pooled reoperation rate was 3.8% across 1106 patients.

CONCLUSIONS

The use of iMRI as an adjunct significantly increases GTR for both microscopic and endoscopic resection of pituitary adenomas, with comparable benefits for both functioning and nonfunctioning adenomas. Satisfactory endocrinologic and visual outcomes were achieved.

Adjunctive Benefit of High-Field 3 Tesla MRI Guidance in Endoscopic Transsphenoidal Resection of Pituitary Adenoma

Introduction Pituitary adenomas (PAs) although benign, are difficult to resect intracranial tumors and their residues are associated with morbidity and reduced quality of life. Thus, gross total resection (GTR) is the goal for all PAs. Role of various modalities for better intraoperative visualization and thus improve resection of adenoma have been tested and each have their pros and cons. The aim of this paper is to analyze adjunctive benefit of high-field 3 Tesla intraoperative magnetic resonance imaging (iMRI) in PAs resection by endoscopic transnasal transsphenoidal surgery (eTSS).

Materials and Methods A total of 50 patients who underwent iMRI-guided eTSS were included. MRI findings in preoperative, intraoperative, and 3 months postoperative stage were compared. Adjunctive value of iMRI in improving resection rates of adenoma, postoperative endocrinological outcomes, need for adjuvant radiotherapy, and postoperative cerebrospinal fluid leak rates was assessed.

Results High-field 3 Tesla iMRI helped us to detect residues in 24 (48%) patients and iMRI-guided second look surgery increased our GTR rates from initial 52 to 80% and also helped us to identify and achieve 100% GTR in intrasellar residues and parasellar residues that were medial to medial carotid tangential line. With better resection rates, need for adjuvant radiotherapy was also reduced and only 2% received adjuvant radiotherapy. Average increase in surgical time with the use of iMRI was 38.78 minutes without any side effects pertaining to prolonged surgery.

Conclusion High-field iMRI is a useful adjunct in assessment and improvement in extent of resection of PA by endoscopic transsphenoidal surgery. Also, it was found beneficial in preserving normal anatomical gland and, thus, reducing the need for postoperative adjuvant hormonal and radiation therapy.

Do We Need Intraoperative Magnetic Resonance Imaging in All Endoscopic Endonasal Pituitary Adenoma Surgery Cases? A Retrospective Study

There are previous reports investigating effectiveness of intraoperative magnetic resonance imaging (IO-MRI) in pituitary adenoma surgery but there is no clear data in the literature recommending when there is no need of intraoperative scan. This retrospective analysis was based on determining which patients does not need any IO-MRI scan following endoscopic endonasal pituitary adenoma surgery. Patients with functional or non-functional pituitary adenomas that were operated via endoscopic endonasal approach (EEA) between June 2017 and May 2019 were enrolled. Patients younger than 18 years old, patients who did not underwent IO-MRI procedure or not operated via EEA were excluded from the study. Hence, this study is designed to clarify if IO-MRI is useful in both functional and non-functional pituitary adenomas, functional adenomas did not split into subgroups. A total of 200 patients treated with pituitary adenoma were included. In Knosp Grade 0 – 2 group, primary surgeon’s opinion and IO-MRI findings were compatible in 150 patients (98.6%). In Knosp Grade 3 – 4 correct prediction were performed in 32 (66.6%) patients. When incorrectly predicted Knosp Grade 3 – 4 patients (n = 16) was analyzed, in 13 patients there were still residual tumor in cavernous sinus and in 3 patients there were no residual tumor. Fisher’s exact test showed there is a statistically significant difference of correct prediction between two different Knosp Grade groups (two-tailed P < 0.0001). Eighteen patients had a residual tumor extending to the suprasellar and parasellar regions which second most common site for residual tumor. Our findings demonstrate that there is no need of IO-MRI scan while operating adenomas limited in the sellae and not invading the cavernous sinus. However, we strongly recommend IO-MRI if there is any suprasellar and parasellar extension and/or cavernous sinus invasion.

Impact of intraoperative magnetic resonance imaging on gross total resection, extent of resection, and residual tumor volume in pituitary surgery: systematic review and meta-analysis

BACKGROUND

Residual tumor tissue after pituitary adenoma surgery, is linked with additional morbidity and mortality. Intraoperative magnetic resonance imaging (ioMRI) could improve resection. We aim to assess the improvement in gross total resection (GTR), extent of resection (EOR), and residual tumor volume (RV) achieved using ioMRI.

METHODS

A systematic review was carried out on PubMed/MEDLINE to identify any studies reporting intra- and postoperative (1) GTR, (2) EOR, or (3) RV in patients who underwent resection of pituitary adenomas with ioMRI. Random effects meta-analysis of the rate of improvement after ioMRI for these three surgical outcomes was intended.

RESULTS

Among 34 included studies (2130 patients), the proportion of patients with conversion to GTR (∆GTR) after ioMRI was 0.19 (95% CI 0.15-0.23). Mean ∆EOR was + 9.07% after ioMRI. Mean ∆RV was 0.784 cm3. For endoscopically treated patients, ∆GTR was 0.17 (95% CI 0.09-0.25), while microscopic ∆GTR was 0.19 (95% CI 0.15-0.23). Low-field ioMRI studies demonstrated a ∆GTR of 0.19 (95% CI 0.11-0.28), while high-field and ultra-high-field ioMRI demonstrated a ∆GTR of 0.19 (95% CI 0.15-0.24) and 0.20 (95% CI 0.13-0.28), respectively.

CONCLUSIONS

Our meta-analysis demonstrates that around one fifth of patients undergoing pituitary adenoma resection convert from non-GTR to GTR after the use of ioMRI. EOR and RV can also be improved to a certain extent using ioMRI. Endoscopic versus microscopic technique or field strength does not appear to alter the impact of ioMRI. Statistical heterogeneity was high, indicating that the improvement in surgical results due to ioMRI varies considerably by center.

A Novel Intraoperative Ultrasound Probe for Transsphenoidal Surgery: First-in-human study

Background. Ultrasound has been explored as an alternative, less bulky, less time-consuming and less expensive means of intraoperative imaging in pituitary surgery. However, its use has been limited by the size of its probes relative to the transsphenoidal corridor. We developed a novel prototype that is more slender than previously reported forward-viewing probes and, in this report, we assess its feasibility and safety in an initial patient cohort. Method. The probe was integrated into the transsphenoidal approach in patients with pituitary adenoma, following a single-centre prospective proof of concept study design, as defined by the Innovation, Development, Exploration, Assessment and Long-Term Study (IDEAL) guidelines for assessing innovation in surgery (IDEAL stage 1 - Idea phase). Results. The probe was employed in 5 cases, and its ability to be used alongside the standard surgical equipment was demonstrated in each case. No adverse events were encountered. The average surgical time was 20 minutes longer than that of 30 contemporaneous cases operated without intraoperative ultrasound. Conclusion. We demonstrate the safety and feasibility of our novel ultrasound probe during transsphenoidal procedures to the pituitary fossa, and, as a next step, plan to integrate the device into a surgical navigation system (IDEAL Stage 2a - Development phase).

10 Years' Experience of Using Low-Field Intraoperative MRI in Transsphenoidal Surgery for Pituitary Adenoma: Results of the Swiss Pituitary Registry (SwissPit)

BACKGROUND

For 20 years, several studies have reported intraoperative magnetic resonance imaging (iMRI) utility to achieve gross total resections in transsphenoidal pituitary adenoma surgery. Although few studies on low-field iMRI included >100 patients, data on hormonally active tumors remain scarce and follow-up times are <3 years. This is not sufficient to judge the long-term efficiency of the use of low-field iMRI. The aim of this retrospective study is to report the detailed outcome of iMRI-controlled transsphenoidal surgery in >200 patients during a follow-up exceeding 5 years.

METHODS

Patients undergoing surgery for pituitary adenoma by iMRI-controlled, endoscopically assisted transsphenoidal surgery at the authors' institution between 2006 and 2016 were eligible for inclusion. Data were collected in the Swiss Pituitary Registry. A Polestar 0.15T-scanner was used.

RESULTS

A total of 231 patients had surgery for 160 nonfunctioning adenomas; 28 hGH-, 27 PRL-, 10 ACTH-secreting and 6 mixed adenomas and were followed for 62 months (9-178). Additional iMRI-guided resections were possible in 54% and increased the gross total resection rate by 4% (P = 0.004). Remission rates were as follows: nonfunctioning adenoma, 53%; acromegaly, 61%; prolactinoma, 50%; Cushing disease, 90%. Tumor regrowth and recurrence was detected at a mean time of 24 and 63 months, respectively. Recovery of deficient hormone axes was detected in 22% to 27%. The risk for new postoperative hormonal deficiencies was 15%. Postoperative relieve of visual field and visual acuity deficiencies was seen in 94 (86%) and 73 (81%) patients, respectively.

CONCLUSION

Judged by long-term follow-ups of >200 nonfunctioning/functioning pituitary adenomas, the use of low-field iMRI in transsphenoidal surgery increases resection rates and sustainably influences outcomes.

Pituitary Adenomas and Invasiveness from Anatomo-Surgical, Radiological, and Histological Perspectives: A Systematic Literature Review

Invasiveness in pituitary adenomas has been defined and investigated from multiple perspectives, with varying results when its predictive value is considered. A systematic literature review, following PRISMA guidelines, was performed, searching PubMed and Scopus databases with terms that included molecular markers, histological, radiological, anatomical and surgical data on invasiveness of pituitary adenomas. The results showed that differing views are still present for anatomical aspects of the sellar region that are relevant to the concept of invasiveness; radiological and histological diagnoses are still limited, but might improve in the future, especially if they are related to surgical findings, which have become more accurate thanks to the introduction of the endoscope. The aim is to achieve a correct distinction between truly invasive pituitary adenomas from those that, in contrast, present with extension in the parasellar area through natural pathways. At present, diagnosis of invasiveness should be based on a comprehensive analysis of radiological, intra-operative and histological findings.

Intra-operative MRI vs endoscopy in achieving gross total resection of pituitary adenomas: a systematic review

BACKGROUND

Intraoperative magnetic resonance imaging (iMRI) is a technology that may improve rates of gross total resection (GTR) for pituitary adenomas. The endoscope is another less expensive technology, which also may maximize resection rates. A direct comparison of these approaches and their additive benefit has never been performed.

METHODS

A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) standard. PubMed and Embase databases were searched for studies that examined GTR for pituitary adenoma resection with either endoscopic transsphenoidal surgery (eTSS), microscopic transsphenoidal surgery with iMRI (mTSS + iMRI), or endoscopic transsphenoidal surgery with iMRI (eTSS + iMRI).

RESULTS

Eighty-five studies that reported GTR rates in 7124 pituitary adenoma patients were identified. For all pituitary adenomas, eTSS had a pooled proportion of GTR of 68.9% (95% CI 64.7-73.0%) which was similar to that of mTSS + iMRI (GTR 68.3%; 95% CI = 59.4-76.5%) and eTSS + iMRI (GTR 70.7%; 95% CI = 56.9-89.6%). For the subgroup of pituitary macroadenomas, pooled proportions for GTR were similar between eTSS and mTSS + iMRI (eTSS: GTR 59.4%; 95% CI = 49.6-68.7% vs mTSS + iMRI: GTR 68.8%; 95% CI = 57.3-79.3%), and higher for eTSS + iMRI (81.1%; 95% CI = 75.5-86.2%). The post-operative CSF leak proportion for eTSS (4.7%; 95% CI = 3.6-5.9%) was similar to that for eTSS + iMRI (3.7%; 95% CI = 1.6-6.5%) and mTSS + iMRI (4.6%; 95% CI = 2.0-8.3%). No direct statistical comparisons could be performed.

CONCLUSION

Final GTR proportions are similar whether the surgeon uses a microscope supplemented with iMRI or endoscope with or without iMRI. The benefit of the two technologies may be complementary for macroadenomas. These findings are important to consider when comparing the efficacy of different technical strategies in the management of pituitary adenomas.

High-Field Intraoperative Magnetic Resonance Imaging Increases Extent of Resection and Progression-Free Survival for Nonfunctioning Pituitary Adenomas

BACKGROUND

The effect of intraoperative magnetic resonance imaging (iMRI) on tumor control during endoscopic transsphenoidal surgery (TSS) for nonfunctioning pituitary adenomas (NFPAs) has not yet been completely characterized. The present study assessed the effect of the iMRI findings on gross total resection (GTR) and progression-free survival at a mean follow-up of 62 ± 9.4 months.

METHODS

Retrospective analyses were performed on the data from 133 consecutive patients with NFPA who had undergone endoscopic TSS with iMRI using a 1.5T scanner.

RESULTS

Compared with the first and final iMRI scans, the GTR rate increased from 42.9% to 63.9%. Multivariate logistic regression analysis revealed that a lower GTR rate was associated with a higher Knosp score (odds ratio [OR], 3.612; 95% confidence interval [CI], 1.568-8.321; P = 0.003), an increased tumor volume (OR, 0.926; 95% CI, 0.866-0.991; P = 0.025), and a history of surgery (OR, 0.376; 95% CI, 0.155-0.917; P = 0.031). During follow-up, 8 tumors (9.4%) recurred, and 29 remnants (60.4%) regenerated. The recurrence and regeneration rates were 0.019 and 0.121 patient/year, respectively. Kaplan-Meier analysis revealed that the tumor recurrence rates were lower for patients who had undergone GTR (P < 0.01) compared with those who had not. Univariate Cox regression analysis suggested that the presence of tumor remnants (hazard ratio, 1.546; 95% CI, 1.071-2.232; P = 0.02) was the influencing factor associated with tumor progression.

CONCLUSIONS

High-field iMRI can increase the GTR rate in endoscopic TSS for NPFAs. The increased GTR rate was associated with longer progression-free survival. Cavernous sinus invasion, tumor size, and surgical history were important predictors of GTR in patients with NFPA.

Long-term follow-up after endoscopic trans-sphenoidal surgery or initial observation in clivus chordomas

BACKGROUND

Resection of clivus chordomas through extensive skull base approaches is associated with high mortality and morbidity even in experienced hands. We report our experience with endoscopic trans-sphenoidal surgery, or a "wait-and-scan" strategy in selected patients.

METHOD

Ten patients were diagnosed with clivus chordomas during an 8-year period. Six patients underwent primary treatment with endoscopic trans-sphenoidal surgery, followed by adjuvant proton-beam therapy in three of these patients. Four patients with minor symptoms were followed-up untreated. Mean follow-up was 91 months.

RESULTS

Of the six patients operated on, total or gross total resection was achieved in four, partial resection in one and biopsy was taken in one. Preoperative cranial neuropathies resolved in three out of five patients, and no new cranial nerve palsies were encountered. Postoperative cerebrospinal fluid leak occurred in one patient. Four patients were initially followed-up without any treatment, and three of these have remained stable without tumour progression for a mean of 94 months. Due to a slow, though progressive growth of tumour, one patient was operated on after 80 months of initial observation.

CONCLUSIONS

The natural course of clivus chordomas has yet to be defined. The endoscopic trans-sphenoidal approach is a valid, minimally invasive alternative for the treatment of clival chordomas, and in selected patients a "wait and scan" strategy can be considered. Our long-term results show low mortality and good functional outcome. An endonasal endoscopic trans-sphenoidal approach should be a principal part of the armamentarium of surgeons treating clivus chordomas.

The Ongoing Gap in Availability of Imaging Services at Teaching Versus Nonteaching Hospitals

RATIONALE AND OBJECTIVES

This study aimed to characterize associations between availability of imaging services and intensity of teaching among US hospitals.

MATERIALS AND METHODS

Using the American Hospital Association Annual Survey Database, we studied information regarding the availability of imaging services at general hospitals nationwide in 2007 (4102 hospitals) and in 2012 (3876). Teaching intensity was categorized as Council of Teaching Hospitals (COTH) member, non-COTH teaching hospital (non-COTH member with affiliated medical school and/or residency), and nonteaching hospital. Availability in hospitals of reported basic and advanced imaging modalities, as well as beds, number of employed physicians, and case mix index, was analyzed. Univariable and multivariable trends were assessed.

RESULTS

All 15 assessed modalities showed significant increases in availability with increasing hospital teaching intensity (P < 0.001). Modalities showing the largest differences between COTH and nonteaching hospitals in 2012 were image-guided radiation therapy (78% vs. 14%), positron emission tomography/computed tomography (74% vs. 17%), and single-photon emission computed tomography (88% vs. 35%). The gap between COTH and nonteaching hospitals increased from 43% in 2007 to 57% in 2012 for positron emission tomography/computed tomography, and from 34% to 48% for virtual colonoscopy. COTH status was a significant predictor, independent of beds and employed physicians, for 10 modalities (P < 0.001-0.038). Greater case mix index was significantly associated with availability of advanced, although not basic, modalities.

CONCLUSIONS

Availability of imaging services increased with greater hospital teaching intensity. Differences were most pronounced and sustained over time for advanced modalities. Our findings reflect the greater advanced imaging resources necessary to support the complexity of care rendered at teaching hospitals. This differential must be considered when exploring adjustments to teaching hospitals' funding levels.

Clinical Concerns about Recurrence of Non-Functioning Pituitary Adenoma

Background

Non-functioning pituitary adenomas (NFPA) are clinically challenging because they present at a late stage with local mass effects or hypopituitarism. Surgery for non-functioning pituitary adenoma requires a special strategic approach for both minimal morbidity and radical resection. However, the clinical predictive factors associated with recurrence are limited. Here, we investigated optimal treatment of non-functioning pituitary adenoma.

Methods

We enrolled 289 patients who presented with non-functioning pituitary adenoma between January 2000 and January 2012 and who had received follow-up for at least one year for this retrospective study. Of these patients, 152 were male and 137 were female, with a median age of 51 years (range 15.79 years) and a median follow-up of four years (range 1.12.6 years). Characteristics of patients and tumors were reviewed with electronic medical records and radiologic images, retrospectively.

Results

Of the tumors, 193 were gross-totally resected, 53 were near-totally resected, and 43 were sub-totally resected. The extent of resection and adjuvant radiotherapy were both statistically significant prognostic factors of recurrence. Immunohistochemistry of tumor specimens did not yield consistent results.

Conclusion

With a high rate of recurrence, NFPA should be closely followed-up over a long-term period. Improvement of surgical techniques with advanced surgical equipment and adjuvant radiosurgery would lead to reduce the recurrence rate and improve patients' outcome.

A magnetic resonance imaging-based classification system for indication of trans-sphenoidal hypophysectomy in canine pituitary-dependent hypercortisolism

OBJECTIVES

The objectives of this study were to establish a magnetic resonance imaging-based classification system for canine hyperadrenocorticism according to pituitary gland extension, determine indications for trans-sphenoidal hypophysectomy, and clarify the prognosis for each disease grade.

METHODS

A 5-point classification system (Grades 1 to 5) was developed based on tumour extension in dorsal and cranio-caudal directions. Cases were then classified as Type A: no arterial circle of Willis or cavernous sinus involvement and Type B: cases in which these blood vessels were involved.

RESULTS

Medical records and magnetic resonance imaging data of 37 cases with hyperadrenocorticism were reviewed. Thirty-three cases underwent surgery; 4 Grade 5 cases did not have appropriate indications for surgery, and other therapies were used. Complete resection was achieved for 3, 3, 22 and 1 Grade 1A, 2A, 3A and 3B cases, respectively. Resection was incomplete in 1, 1 and 2 Grade 3A, 3B and 4B cases, respectively. Remission was achieved in 29 cases. Recurrence occurred in 4 cases, all of which were classified as Grade 3.

CLINICAL SIGNIFICANCE

Dogs with Type A, Grade 1 to 3 hyperadrenocorticism had a good prognosis following trans-sphenoidal hypophysectomy. Grade 3B, 4 and 5 cases may not be suitable for this surgery.

Intraoperative magnetic resonance imaging assessment of non-functioning pituitary adenomas during transsphenoidal surgery

PURPOSE

To review the utility of intraoperative imaging in facilitating maximal resection of non-functioning pituitary adenomas (NFAs).

METHODS

We performed an exhaustive MEDLINE search, which yielded 5598 articles. Upon careful review of these studies, 31 were pertinent to the issue of interest.

RESULTS

Nine studies examined whether intraoperative MRI (iMRI) findings correlated with the presence of residual tumor on MRI taken 3 months after surgical resection. All studies using iMRI of >0.15T showed a ≥90% concordance between iMRI and 3-month post-operative MRI findings. 24 studies (22 iMRI and 2 intraoperative CT) examined whether intraoperative imaging improved the surgeon's ability to achieve a more complete resection. The resections were carried out under microscopic magnification in 17 studies and under endoscopic visualization in 7 studies. All studies support the value of intraoperative imaging in this regard, with improved resection in 15-83% of patients. Two studies examined whether iMRI (≥0.3T) improved visualization of residual NFA when compared to endoscopic visualization. Both studies demonstrated the value of iMRI in this regard, particularly when the tumor is located lateral of the sella, in the cavernous sinus, and in the suprasellar space.

CONCLUSION

The currently available literature supports the utility of intraoperative imaging in facilitating increased NFA resection, without compromising safety.

Pituitary surgery and volumetric assessment of extent of resection: a paradigm shift in the use of intraoperative magnetic resonance imaging

OBJECTIVE

The aim of this study was to quantitatively assess the role of intraoperative high-field 3-T MRI (3T-iMRI) in improving the gross-total resection (GTR) rate and the extent of resection (EOR) in endoscopic transsphenoidal surgery (TSS) for pituitary adenomas.

METHODS

Radiological and clinical data from a prospective database were retrospectively analyzed. Volumetric measurements of adenoma volumes pre-, intraoperatively, and 3 months postoperatively were performed in a consecutive series of patients who had undergone endoscopic TSS. The quantitative contribution of 3T-iMRI was measured as a percentage of the additional rate of GTR and of the EOR achieved after 3T-iMRI.

RESULTS

The cohort consisted of 50 patients (51 operations) harboring 33 nonfunctioning and 18 functioning pituitary adenomas. Mean adenoma diameter and volume were 21.1 mm (range 5–47 mm) and 5.23 cm3 (range 0.09–22.14 cm3), respectively. According to Knosp's classification, 10 cases were Grade 0; 8, Grade 1; 17, Grade 2; 12, Grade 3; and 4, Grade 4. Gross-total resection was the surgical goal (targeted [t]GTR) in 34 of 51 operations and was initially achieved in 16 (47%) of 34 at 3T-iMRI and in 30 (88%) of 34 cases after further resection. In this subgroup, the EOR increased from 91% at 3T-iMRI to 99% at the 3-month MRI (p < 0.05). In the 17 cases in which subtotal resection (STR) had been planned (tSTR), the EOR increased from 79% to 86% (p < 0.05) and GTR could be achieved in 1 case. Intrasellar remnants were present in 20 of 51 procedures at 3T-iMRI and in only 5 (10%) of 51 procedures after further resection (median volume 0.15 cm3). Overall, the use of 3T-iMRI led to further resection in 27 (53%) of 51 procedures and permitted GTR in 15 (56%) of these 27 procedures; thus, the GTR rate in the entire cohort increased from 31% (16 of 51) to 61% (31 of 51) and the EOR increased from 87% to 95% (p < 0.05).

CONCLUSIONS

The use of high-definition 3T-iMRI allowed precise visualization and quantification of adenoma remnant volume. It helped to increase GTR and EOR rates in both tGTR and tSTR patient groups. Moreover, it helped to achieve low rates of intrasellar remnants. These data support the use of 3T-iMRI to achieve maximal, safe adenoma resection.

Current imaging techniques for the diagnosis of pituitary adenoma

Stepwise improvements in the imaging of pituitary adenomas in the last 100 years have had a tremendous impact on patient care. Pituitary tumors are now diagnosed earlier in the time course of the disease, improving chances of endocrine and visual recovery. There is improved pre-surgical planning due to a better understanding of the investment of the tumor around important surrounding parasellar structures. Approaches to tumors are now safer due to stereotactic navigation and residual disease can be radiographically followed for a lifetime and treated prior to irreversible neurological damage. Furthermore, adjuvant radiotherapy can be more precisely delivered to the tumor bed with the aid of higher resolution images. Thanks to these incremental improvements previously formidable macroadenomas, which carried a high risk for morbidity and residual disease, can now be treated safely and effectively. Here, we review modern imaging modalities used to diagnose pituitary adenomas, and identify areas for further improvement.

"Intrasellar Balloon Technique" in intraoperative MRI guided transsphenoidal endoscopic surgery for sellar region tumors. Usefulness on image interpretation and extent of resection evaluation. Technical note

BACKGROUND

Intraoperative magnetic resonance imaging (iMRI) is an effective and proven tool in transsphenoidal endoscopic surgery. However, image interpretation is not always easy and can be hindered by the presence of blood, tumor remains or the displacement of surrounding structures. In this article we present a novel technique based on using intrasellar ballons to reduce these difficulties and facilitate the surgeon's intraoperative assessment by iMRI.

METHODS

Eighteen patients with pituitary macroadenomas underwent transsphenoidal surgery during 2013-2014 under low-field iMRI control (PoleStar N20, 0.15 T). Intrasellar balloons were used in all of them to assess the presence of tumoral remnants. We compared the findings in iMRI and postoperative high-field MRI control scans and also analyzed the number of intermediate imaging controls needed during surgery using this technique.

RESULTS

In total, of the 18 patients, 14 underwent a complete resection. In the remaining four patients, a safe maximal resection was performed, leaving a remnant because of cavernous sinus invasion. In all cases, the balloons were a major help in distinguishing the anatomical structures from the tumoral remnants. Fewer imaging controls were required, and there were no false-positives or negative intraoperative findings. No complications related to the technique were registered.

CONCLUSION

The "intrasellar balloon technique" is a useful tool that facilitates surgeons' intraoperative decision making. It is an important contribution to overcome the limitations of low-field iMRI as it provides a precise delineation of the resection margins, reduces false-positives and -negatives, and decreases the number of intermediate imaging controls required.

Pure endoscopic transsphenoidal surgery for functional pituitary adenomas: outcomes with Cushing's disease

BACKGROUND

This study was performed to examine patient outcomes following pure endoscopic transsphenoidal surgery (ETS) for Cushing's disease (CD).

METHOD

We studied 64 consecutive patients who underwent 69 endoscopic transsphenoidal procedures. Radiological evaluation comprised detailed examination of preoperative magnetic resonance images (MRI), including positron emission tomography (PET) for select cases. Inferior petrosal sinus sampling (IPSS) was not performed for any patient. Remission was defined by the presence of hypocortisolemia with requirement for steroid replacement therapy or eucortisolemia with suppression to <1.8 μg/dl after 1 mg dexamethasone on evaluation at least 3 months after surgery.

RESULTS

Preoperative MRI was abnormal in 87.5 % of cases and included 11 macroadenomas (17.2 %). PET was used to localize the adenoma in four cases. For microadenomas, operative procedures executed were as follows: selective adenomectomy (n = 15), enlarged adenomectomy (n = 21) and subtotal/hemihypophysectomy (n = 17). Overall, pathological confirmation of an adenoma was possible in 58 patients (90.6 %). Forty-nine patients (76.6 %) developed hypocortisolemia (<5 μg/dl) in the early postoperative period. Mean follow-up was 20 months (range 6-18 months). Remission was confirmed in 79.7 % of the 59 cases followed up for >3 months and was superior for microadenomas (86.4 %) versus macroadenomas (55.6 %) and equivocal MRI adenomas (66.7 %). Postoperative CSF rhinorrhea occurred in five patients, and new endocrine deficits were noted in 17.1 % patients. A nadir postoperative cortisol <2 μg/dl in the 1st week after surgery was highly predictive of remission (p = 0.001).

CONCLUSION

ETS allows for enhanced intrasellar identification of adenomatous tissue, providing remission rates that are comparable to traditional microsurgery for CD. The best predictor of remission remains induction of profound hypocortisolemia in the early postoperative period.

Non-functioning pituitary adenoma: when and how to operate? What pathologic criteria for typing?

After diagnosis of non-functioning pituitary adenoma and impact assessment (pituitary deficiency, visual field disorder), the question of management arises between surgery and surveillance. This part of the Consensus document aims to clarify the principal situations encountered in clinical practice (visual disorder, pituitary deficiency, asymptomatic adenoma, etc.), so as to determine which ones indicate surgery and which ones simple surveillance. Particular contexts are also dealt with (elderly patients, young women hoping for pregnancy, etc). The principal surgical techniques (microscopy, endoscopy, etc.) are also considered. Finally, in case of surgery, the principal pathologic criteria are specified (immunolabeling, proliferation markers, etc.).

Surgical complications after transsphenoidal microscopic and endoscopic surgery for pituitary adenoma: a consecutive series of 506 procedures

BACKGROUND

This single-institution, consecutive series of transsphenoidal procedures included all patients in a defined population of 2.6 million inhabitants who underwent surgery during a specific time period.

OBJECTIVE

We sought to determine the surgical complication rate and overall survival rate after transsphenoidal surgery for pituitary adenoma.

METHODS

All transsphenoidal procedures for histologically verified pituitary adenomas performed between September 2002 and February 2011 at our institution were included in this study. The data were obtained from a prospectively collected database and from reviewing medical records. No patients were lost to follow-up, and the median follow-up time was 28 months.

RESULTS

A total of 506 transsphenoidal procedures were performed on 446 patients. There were 268 microscopic and 238 endoscopic procedures involving 352 non-functioning and 154 hormone-secreting adenomas. A total of 73% of the procedures were primary surgeries, and 27% were repeat surgeries for tumor recurrence. The overall complication rate was 9.1%. The three most frequent complications were cerebrospinal fluid (CSF) leakage (4.7%), meningitis (2%), and visual deterioration (2%). Multivariate analyses showed that the overall risk for complications increased with older age, surgery for recurrent tumors, and surgery performed by a low-volume surgeon. There was no significant difference in the overall complication rate between the microsurgical and endoscopic techniques. The rate of surgical mortality was 0.6%, and the overall survival rates at 1 and 5 years were 95% and 90%, respectively. The only negative predictor of survival was older age.

CONCLUSIONS

Transsphenoidal surgery for pituitary adenomas has a low complication rate and a low rate of mortality. We did not find a significant difference in the complication rate between endoscopic and microscopic techniques.

Radiofrequency heating and magnetic field interactions of fixed partial dentures during 3-tesla magnetic resonance imaging

OBJECTIVE

This study evaluated the heating and magnetic field interactions of fixed partial dentures in a 3-Tesla (3T) magnetic resonance imaging (MRI) environment.

STUDY DESIGN

Three substructure materials (Co-Cr, Ni-Cr, ZrO₂) were used to fabricate twelve 4-retained bridges and 12 crowns. Specimens were evaluated at 3T for radiofrequency heating and magnetic field interactions. One-way analysis of variance (ANOVA) test was used to compare continuous variables of temperature change. Significance was set at P < .05. Translational attraction and torque values of specimens were also evaluated.

RESULTS

None of the groups exhibited excessive heating (mean temperature change, < 1.4 °C), with maximum increase at the end of the T-1. Moreover, in all groups, only relatively minor magnetic field interactions that would not cause movement in situ were observed.

CONCLUSION

The study findings indicated that patients with fixed partial dentures (single crown or bridge) fabricated from Co-Cr, Ni-Cr, and zirconia substructures may safely undergo MRI at up to 3T.

Magnetic resonance imaging criteria to predict complete excision of parasellar pituitary macroadenoma on postoperative imaging

Purpose To evaluate preoperative magnetic resonance imaging (MRI) criteria for their ability to predict the complete removal of parasellar pituitary macroadenoma on the 3-month postoperative MRI. Methods Dedicated pre- and postoperative pituitary MRI studies were reviewed in 49 patients who had undergone transsphenoidal surgery for macroadenomas with potential unilateral parasellar involvement. Twelve preoperative MRI findings and postoperative MRI outcomes were statistically compared. Results Depiction of the inferolateral (positive predictive value [PPV]: 0.6; negative predictive value [NPV], 0.92) and lateral (PPV: 0.65; NPV: 0.85) compartments of the cavernous sinus and the percentage of intracavernous carotid artery encasement (PPV: 0.63; NPV, 1.0 for <50% encasement) were the only criteria significantly predictive of parasellar tumor complete resection. The odds ratios indicated that depiction of the lateral venous or inferolateral venous compartments increased the likelihood of a complete resection by 6 times, whereas for every 25% reduction in intracavernous carotid artery encasement, the chance of a complete resection increased 3.4 times. Conclusion The preoperative MR imaging features that are useful in predicting the complete removal of the parasellar component of a pituitary adenoma as assessed by postoperative MRI are (1) depiction of the lateral and inferolateral compartment of the cavernous sinus and (2) decreasing encasement of the intracavernous carotid artery.