Extracapsular en bloc resection in pituitary adenoma surgery

The Learning Curve for Endoscopic Endonasal Transsphenoidal Pituitary Surgery: Evaluating Endocrine Outcomes

OBJECTIVE

In South Australia endoscopic endonasal approach (EEA) pituitary surgery has been practiced since 2006, largely by two neurosurgeons with a small fellowship-trained otolaryngology team. The aim of this cohort study was to determine if a "learning curve" can be established over this time period, as represented by structural and endocrine patient outcomes.

METHOD

Retrospective cohort study of patients undergoing EEA surgery between 2006 and 2021 in Adelaide, South Australia at three tertiary teaching hospitals.. Cases were divided by each surgeon and split into groups of sequential 40 cases. Endocrine assessment pre- and post-operatively involved static pituitary and end-organ hormones, with dynamic tests as required, assessed by an pituitary endocrinologist. Each hormonal axis (gonadal, cortisol, thyroid, prolactin and growth hormone) was documented preoperatively and at an early and long term follow up at 1-2 and 12 months, respectively.

RESULTS

The study included a cohort of 443 pituitary adenomas managed with endoscopic endonasal transsphenoidal surgery in a consecutive fashion between two neurosurgeons over 16-years. Gross tumour resection but not visual visual outcomes improved with surgical experience but this outcome may be neurosurgeon dependent. Endocrine outcomes were not consistently improved with experience, but lower rates of hypopituitarism were seen with experience with one neurosurgeon. Average follow up was approximately 5 years, and a minimum follow up of 12 months for all patients.

CONCLUSIONS

We present long term endocrine follow up for patients with functional and non-functional adenomas. Improved rates of gross tumour resection were evident with with surgical experience. However, there was no apparent change in post-operative endocrine outcomes.

Extracapsular Resection of Pituitary Adenomas: A Systematic Review

There is considerable variation in the surgical techniques for transsphenoidal excision of pituitary tumors. Recently, an extracapsular method has been developed that involves using the tumor pseudocapsule as a dissection plane to increase the extent of resection. This review assessed the outcomes of this new approach as compared with standard transsphenoidal surgery. We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library, MEDLINE/PubMed, the US National Institutes of Health Ongoing Trials Register (ClinicalTrials.gov), the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP; apps.who.int/trialsearch), and LILACS databases for relevant literature and checked reference lists of relevant articles. Randomized controlled trials and prospective and retrospective cohort studies comparing extracapsular and intracapsular resection of pituitary tumors were included in the review. Five cohort studies with 1,588 participants were included. Extracapsular resection was associated with a higher likelihood of complete excision (relative risk [RR] 1.31, 95% confidence interval [CI] 1.01–1.70, p = 0.04) and endocrinologic remission (RR 1.26, 95% CI 1.03–1.54, p = 0.02). Because there was a significant risk of bias and substantial heterogeneity, the estimates of effect may not be robust. In patients with pituitary adenomas undergoing transsphenoidal excision, extracapsular resection may be associated with higher rates of complete excision and endocrinologic remission, but the evidence is not strong. Hence, randomized controlled trials to determine the magnitude of benefit and identify an improvement in progression-free or overall survival are warranted.

Endoscopic endonasal surgery for non-invasive pituitary neuroendocrinology tumors with incomplete pseudocapsule

Background

Pituitary neuroendocrinology tumors (PitNETs) with pseudocapsule can be effectively removed by the pseudocapsule-based extracapsular resection technique. In the areas without pseudocapsule, the tumor cells can spread into the adjacent tissues at the cellular level, which brings a great challenge to achieving total tumor resection.

Methods

Our surgical strategy for PitNETs with an incomplete pseudocapsule is to combine the pseudocapsule-based extracapsular resection technique with the intensive excision technique for the removal of the tumor. Specifically, the pseudocapsule-based extracapsular resection technique is applied in the areas with pseudocapsule, while in the areas without pseudocapsule, the intensive excision technique bounded by adjacent normal structures is adopted. Moreover, a pathological examination was performed to determine the situations of pseudocapsule and tumor cell remnant.

Results

All growth hormone-secreting PitNETs achieved biochemical remission after surgery. There was no deterioration of pituitary functions postoperatively, and the preoperative hypopituitarism had improved in all patients postoperatively. In total, two cases suffered a transient diabetes insipidus, and intraoperative cerebrospinal fluid leakage was observed in two cases but no postoperative cerebrospinal fluid leakage in all cases. There was no recurrence during the follow-up. The fragmental pseudocapsule and small tumor remnants were found in the majority of suspicious tissues by histological staining.

Conclusion

The effectiveness and safety of the surgical strategy were preliminarily explored for removing PitNETs without incomplete pseudocapsules. In overview, the pseudocapsule-based extracapsular resection technique is applied in areas with pseudocapsule, while the intensive excision bounded by adjacent normal structures is adopted in other areas.

Arachnoid Remodeling by Clipping Technique Facilitates Surgical Maneuverability during Transsphenoidal Surgery for Pituitary Macroadenoma

Objective

Pituitary adenomas frequently extend into the suprasellar space. After a suprasellar tumor is removed, the superiorly extended arachnoid becomes redundant and sinks down into the intrasellar space which often hiders visualization and accessibility to the hidden space behind the evaginated arachnoid. We introduced arachnoid remodeling by clipping technique, and evaluated its usefulness and safety during TSS.

Methods

Total 223 patients who underwent arachnoid remodeling with our new clipping technique were included. Redundant arachnoid was clipped along the dural edge with multiple 2.6-mm titanium clips until the redundant arachnoid membrane no longer blocked the surgical route. To check for possible deterioration of hormonal function by this technique, we assessed anterior pituitary function of 166 patients who underwent arachnoid remodeling by clipping and compared this with those of other 429 control patients.

Results

Our technique greatly enhanced the accessibility and visualization of intrasellar and parasellar spaces, both of which are generally hindered by redundant arachnoid during transsphenoidal surgery (TSS). We found no difference in anterior pituitary function between a clip-assisted arachnoid remodeling group and the control group, implying that this technique does not result in hypopituitarism.

Conclusion

During TSS for pituitary adenomas with suprasellar extension, arachnoid remodeling by clipping technique is very useful and convenient for the management of the redundant arachnoid membrane to enhance visualization and surgical accessibility.

Comparison of outcomes between intracapsular resection and pseudocapsule-based extracapsular resection for pituitary adenoma: a systematic review and meta-analysis

Background

Transsphenoidal surgery is the preferred first-line therapy for most pituitary adenoma(PA), and the conventional strategy of treatment is intracapsular resection(IR). The protocol of extracapsular resection(ER), which considers the pseudocapsule as the PA boundary for surgical removal, has also been introduced gradually. In this study, the clinical efficacies and complications were explored and compared between these two procedures.

Methods

A systematic literature review was performed in the PubMed, EMBASE, Web of Science and Cochrane databases. Articles comparing between IR and ER were included.

Results

There were 7 studies containing 1768 cases in accordance with the inclusion criteria. Although the meta-analysis showed no significant difference in complete resection, a sensitivity analysis revealed that ER was more conducive to total PA resection than IR. Moreover, we found a significant difference in favor of ER regarding biochemical remission. Furthermore, there was no significant difference in the incidence rate of certain complications, such as hormone deficiency, diabetes insipidus, intraoperative cerebrospinal fluid(CSF) and postoperative CSF leakage. However, a sensitivity analysis suggested that IR decreased the risk of intraoperative CSF leakage.

Conclusions

This meta-analysis unveiled that ER contributed to biochemical remission. To some extent, our results also showed that ER played a positive role in complete resection, but that IR reduced the incidence of intraoperative CSF leakage. However, the available evidence needs to be further authenticated using well-designed prospective, multicenter, randomized controlled clinical trials.

Pseudocapsule-Based Resection for Pituitary Adenomas via the Endoscopic Endonasal Approach

Introduction

The endoscopic endonasal approach (EEA) is a safe and effective treatment for pituitary adenomas (PAs). Since extracapsular resection (ER) of PAs improves tumor resection and endocrine remission rates, the interface between the pseudocapsule and gland draws increasing attention. However, it is difficult to precisely dissect the tumor along the exact boundary, and complete removal of the tumor increases the risks of normal tissue damage and cerebrospinal fluid (CSF) leakage. In this study, we investigated the extracapsular resection as well as the pseudocapsule histology to evaluate the effectiveness and safety of pseudocapsule-related surgical interventions.

Methods

From December 2017 to December 2019, 189 patients of PAs via EEA in our single center were analyzed retrospectively. The images, operative details, and clinical follow-up of patients were collected. Sixty-four patients underwent pseudocapsule-based ER, and 125 patients also underwent traditional intracapsular resection (IR) with or without intensive excision for FPAs. The clinical characteristics, tumor resection, endocrinological outcomes, and postoperative morbidities of the two groups were compared. Informed consent for publication of our article was obtained from each patient. Histological examination of pseudocapsule was performed using hematoxylin and eosin and reticulin staining.

Results

The gross total recession was 62 (96.9%) in the ER group and 107 (85.6%) cases in the IR group, whereas the endocrine remission rate was 29/31 (93.5%) and 40/53 (75.5%) cases, respectively. Anterior pituitary functions were not aggravated postoperatively in any patient, but transient diabetes insipidus (DI) occurred more in the IR group (64.0%) than in ER (48.4%). Pseudocapsule specimens were obtained in 93 patients, and clusters of small cell aggregation were detected in 11 pseudocapsule specimens (11.8%) whereas other patients showed no remarkable developed pseudocapsule. Intraoperative CSF leak occurred more in the ER group (28.1%) than in the IR group (13.6%), but no difference was seen between two groups postoperatively. No case of intracranial hematoma or pituitary crisis occurred in both groups. After a mean follow-up of 22.8 months, tumor recurrence was observed in 4 (2.1%) cases.

Conclusion

Pseudocapsule-based extracapsular resection of PAs via EEA is an effective and safe procedure to achieve complete resection with high and sustained endocrine remission and without deteriorating pituitary function.

Pseudocapsule and pseudocapsule-based extracapsular resection in pituitary neuroendocrine tumors

Since Costello et al. proposed the concept of pseudocapsule of pituitary neuroendocrine tumors (PitNETs) in 1936, many studies have been published on its occurrence, development process, histopathology, and morphology. Pseudocapsule has been proposed as the anatomical interface between PitNETs and normal pituitary gland, therefore the so-called pseudocapsule-based extracapsular resection (ER) technique was developed as an extracapsular surgery method for PitNETs,which differs from the conventional intracapsular resection (IR). In recent years, ER has also been widely used in patients of different tumor types, sizes, and age groups, because the pseudocapsule can be identified more clearly under the endoscopy. Endoscopic transsphenoidal resection for PitNETs has become the preferred surgical method. We reviewed relevant literatures in the past 10 years, showing that ER could achieve better rate of gross total resection (GTR) and biochemical remission, and reduce tumor recurrence than IR, without increasing postoperative complications. Therefore, the pseudocapsule and ER should be valued by neurosurgeons and actively promoted clinically.

The incidence of postoperative cerebrospinal fluid leakage after elective cranial surgery: a systematic review

Cerebrospinal fluid (CSF) leakage is a major complication after elective neurosurgical procedures. The aim of this systematic literature review is to summarize the incidence rates of postoperative cerebrospinal fluid leakage for neurosurgical procedures, classified by surgical approach. The Pubmed, Cochrane, Embase, and Web of Science databases were searched for studies reporting the outcome of patients undergoing elective neurosurgical procedures. The number of patients, surgical approach, and indication for surgery were recorded for each study. Outcomes related to CSF leakage such as clinical manifestation and treatment were reported as well. One hundred and thirteen studies were included, reporting 94,695 cases. Overall, CSF leaks were present in 3.8% of cases. Skull base surgery had the highest rate of CSF leakage with 6.2%. CSF leakage occurred in 5.9% of anterior skull base procedures, 6.4% of middle fossa, and 5.2% of transpetrosal surgeries. 5.8% of reported infratentorial procedures were complicated by CSF leakage versus 2.9% of supratentorial surgeries. CSF leakage remains a common serious adverse event after cranial surgery. There exists a need for standardized procedures to reduce the incidence of postoperative CSF leakage, as this serious adverse event may lead to increased health care costs.

Sellar and parasellar lesions: multidisciplinary management

Introduction

The endoscopic endonasal transsphenoidal approach to the sella and parasellar regions is now increasingly used for removal of a variety of lesions localized in the ventral skull base. The advantage of the endoscope is enhanced visualization and improved panoramic view that can result in more complete removal of the tumor. An extensive knowledge of the anatomy is mandatory to approach this region.

Materials and methods

From February 2009 to March 2020, the endoscopic endonasal approach was used in 153 patients with sellar and parasellar lesions, at our Institution: 136 pituitary adenomas, 7 craniopharyngiomas, 3 Rathke’s cysts, a tuberculum sellae meningioma, an aneurysm of the internal carotid artery (ICA), a clivus chordoma, a papillary glioneuronal tumor, an histiocytosis, a pituitary metastasis from breast cancer and a chondrosarcoma.

Results

The most common surgical complications were cerebral spinal fluid leak (9), bleeding (2), pituitary abscess (2). Among endocrinological complications, the most important were diabete insipidus (23) and panhypopituitarism (3). Two patients complicated with meningitis. There were no visual worsening and no operative mortality. We had persistence of disease in 20 cases. Twelve patients underwent surgical revision for recurrence of the disease.

Conclusions

Pre-operative planning and collaboration with several specialists are necessary in order to offer the patient the best treatment, minimizing complications.

Sources of residuals after endoscopic transsphenoidal surgery for large and giant pituitary adenomas

BACKGROUND

Giant and large pituitary adenomas (PA) constitute a specific subset of PAs, with gross total resection (GTR) rates frequently not exceeding 50%. Both an anatomical inaccessibility and an inadequate tumor visualization are thought to play a role. This study analyzes risk factors for postoperative residuals after endoscopic transsphenoidal pituitary surgery for large and giant pituitary adenomas.

METHODS

A retrospective analysis of patients with giant and large PA operated between 2015 and 2018 was performed.

RESULTS

Forty patients (13 females, 27 males) were included in the analysis (30 large and 10 giant PAs). The mean MRI follow-up time was 5.9 ± 6.54 months. Overall, GTR was achieved in 29 patients (72.5%), subtotal resection in 9 (22.5%), and the inconclusive result was in 2 (5%). Unexpected residuals represented 7 (77.7%) of all 9 residual tumors. The most frequent intraoperative factor associated with unexpected residual tumors was improper identification of residual tumor due to obstruction of view in 2 (28.5%) cases and inability to distinguish normal tissue from tumor in the other two (28.5%). Sub-analysis based on tumor size revealed that with large PAs, GTR was achieved in 25 (83.3%), STR in 4 (13.3%), and inconclusive in 1 (3.3%) patient. In patients with giant PAs, GTR was achieved in 4 (40%), STR in 5 (50%), and inconclusive in 1 (10%). Analysis of preoperative factors showed a significant association of residual tumors with larger suprasellar AP distance (p = 0.041), retrosellar extension (p = 0.007), and higher Zurich Score (p = 0.029).

CONCLUSION

Large and giant PAs are challenging lesions with high subtotal resection rates. Suprasellar AP distance, retrosellar extension, and higher Zurich Score seem to be significant predictors of degree of resection in these tumors. Improving the intraoperative ability to distinguish tumor from a normal tissue might further decrease the number of unexpected residuals.

Development and clinical validation of a grading system for pituitary adenoma consistency

OBJECTIVE

Pituitary adenoma (PA) consistency, or texture, is an important intraoperative characteristic that may dictate operative dissection techniques and/or instruments used for tumor removal during endoscopic endonasal approaches (EEAs). The impact of PA consistency on surgical outcomes has yet to be elucidated.

METHODS

The authors developed an objective 5-point grading scale for PA consistency based on intraoperative characteristics, including ease of tumor debulking, manipulation, and instrument selection, ranging from cystic/hemorrhagic tumors (grade 1) to calcified tumors (grade 5). The proposed grading system was prospectively assessed in 306 consecutive patients who underwent an EEA for PAs, and who were subsequently analyzed for associations with surgical outcomes, including extent of resection (EOR) and complication profiles.

RESULTS

Institutional database review identified 306 patients who underwent intraoperative assessment of PA consistency, of which 96% were macroadenomas, 70% had suprasellar extension, and 44% had cavernous sinus invasion (CSI). There were 214 (69.9%) nonfunctional PAs and 92 functional PAs (31.1%). Distribution of scores included 15 grade 1 tumors (4.9%), 112 grade 2 tumors (36.6%), 125 grade 3 tumors (40.8%), 52 grade 4 tumors (17%), and 2 grade 5 tumors (0.7%). Compared to grade 1/2 and grade 3 PAs, grade 4/5 PAs were significantly larger (22.5 vs 26.6 vs 27.4 mm, p < 0.01), more likely to exhibit CSI (39% vs 42% vs 59%, p < 0.05), and trended toward nonfunctionality (67% vs 68% vs 82%, p = 0.086). Although there was no association between PA consistency and preoperative headaches or visual dysfunction, grade 4/5 PAs trended toward preoperative (p = 0.058) and postoperative panhypopituitarism (p = 0.066). Patients with preoperative visual dysfunction experienced greater improvement if they had a grade 1/2 PA (p < 0.05). Intraoperative CSF leaks were noted in 32% of cases and were more common with higher-consistency-grade tumors (p = 0.048), although this difference did not translate to postoperative CSF leaks. Gross-total resection (%) was more likely with lower PA consistency score as follows: grade 1/2 (60%), grade 3 (50%), grade 4/5 (44%; p = 0.045). Extracapsular techniques were almost exclusively performed in grade 4/5 PAs. Assignment of scores showed low variance and high reproducibility, with an intraclass correlation coefficient of 0.905 (95% CI 0.815-0.958), indicating excellent interrater reliability.

CONCLUSIONS

These findings demonstrate clinical validity of the proposed intraoperative grading scale with respect to PA subtype, neuroimaging features, EOR, and endocrine complications. Future studies will assess the relation of PA consistency to preoperative MRI findings to accurately predict consistency, thereby allowing the surgeon to tailor the exposure and prepare for varying resection strategies.

Various Strategies of Transsphenoidal Pseudocapsule-Based Extracapsular Resection in Noninvasive Functional Pituitary Adenomas and their Effectiveness and Safety

Introduction

Increasing attention has been paid to the pseudocapsule-based extracapsular resection in transsphenoidal surgery for pituitary adenomas. Prior reports focused more on Cushing disease or nonfunctional pituitary adenomas. In this study we present systematic research, especially concerning all kinds of noninvasive functional pituitary adenomas (NIFPAs) adopting various strategies of extracapsular resection, in order to evaluate the effectiveness and safety of these surgical methods for NIFPAs.

Materials and Methods

From October 2008 to November 2014, 116 patients suffering from NIFPAs underwent pseudocapsule-based extracapsular resection (ER) with different surgical strategies; that is, by a microscope or endoscope via the endonasal transsphenoidal approach. During the same period, 90 patients suffering NIFPAs also underwent traditional transsphenoidal intracapsular resection (IR). In different postoperative periods, we re-examined the endocrine series and recorded the complications. Enhanced magnetic resonance imaging examination was also performed three months later.

Results

In the ER and IR group, the tumors were completely removed in 97 (83.7%) and 62 (68.9%) cases, whereas the endocrine disorders were remitted in 89 (76.7%) and 53 (58.9%) cases, respectively. Statistical analyses to compare the overall complete resection rates and the overall endocrine remission rates in both groups showed significant differences (P = 0.028 and 0.006, respectively). Intraoperative rhinorrhea occurred in 26.7% patients of the ER group and 13.3% of the IR group, showing a significant difference (P = 0.019). Transient diabetes insipidus occurred in 73.3% patients of the ER group and 63.3% of the IR group, with no difference between groups (P = 0.126). There was no case with intracranial hematoma or pituitary crisis in both the groups.

Conclusion

With our various surgical strategies of ER, the patients can achieve content imaging resection, high and sustained endocrine remission, which are effective and safe for NIFPAs.

Precision Therapy in Acromegaly Caused by Pituitary Tumors: How Close Is It to Reality?

Acromegaly presents with an enigmatic range of symptoms and comorbidities caused by chronic and progressive growth hormone elevations, commonly due to endocrinologic hypersecretion from a pituitary gland tumor. Comprehensive national acromegaly databases have been appearing over the years, allowing for international comparisons of data, although still presenting varying prevalence and incidence rates. Lack of large-scale analysis in geographical and ethnic differences in clinical presentation and management requires further research. Assessment of current and novel predictors of responsiveness to distinct therapy can lead to multilevel categorization of patients, allowing integration into new clinical guidelines and reduction of increased morbidity and mortality associated with acromegaly. This review compares current data from epidemiological studies and assesses the present-day application of prognostic factors in medical practice, the reality of precision therapy, as well as its future prospects in acromegaly, with a special focus on its relevance to the South Korean population.

Immediate postoperative measurement of thyroid-stimulating hormone as an early predictor of remission in thyroid-stimulating hormone-secreting pituitary adenomas

OBJECTIVE

Thyroid-stimulating hormone (TSH)-secreting pituitary adenoma (TSHoma) is a rare type of pituitary adenoma; thus, little is known about TSHomas. The purpose of this study was to analyze clinical characteristics and therapeutic outcomes of TSHomas based on a single-center experience. The authors also searched for reliable preoperative and early postoperative factors that could predict long-term endocrinological remission.

METHODS

The clinical, radiological, and pathological characteristics and surgical and endocrinological outcomes of 31 consecutive cases of TSHomas that were surgically treated between 2005 and 2017 were reviewed retrospectively. Preoperative factors were evaluated for their ability to predict long-term remission by comparing remission and nonremission groups. TSH and free thyroxine levels were measured at 2, 6, 12, 18, and 24 hours after surgery to determine whether they could predict long-term remission.

RESULTS

Gross-total removal of tumor was achieved in 28 patients (90.3%), and 26 patients (83.9%) achieved endocrinological remission by surgery alone based on long-term endocrinological follow-up (median 50 months, range 32-81 months). The majority of the tumors were solid (21/31, 67.7%), and en bloc resection was possible in 16 patients (51.6%). Larger tumor size and tumor invasion into cavernous sinus and sphenoid sinus were strong predictors of lower rates of endocrinological remission. Immediate postoperative TSH level at 12 hours after surgery was the strongest predictor, with a 0.62 μIU/mL cutoff. Postoperative complications included CSF rhinorrhea in one patient and epistaxis in another patient, who underwent additional surgical treatment for the complications.

CONCLUSIONS

Tumor size and extent are major prognostic factors for both extent of resection and endocrinological remission. The consistency of TSHomas was more likely to be solid, which makes extracapsular dissection more feasible. Long-term remission of TSHomas could be predicted even during the early postoperative period.

Peel-off resection of the pituitary gland for functional pituitary adenomas: pathological significance and impact on pituitary function

PURPOSE

Functional pituitary adenomas (FPAs) lacking a well-defined pseudocapsule can invade the adjacent pituitary gland. In such situations, peel-off resection of the adjacent pituitary gland after selective adenomectomy might lead to complete tumor removal, resulting in optimal endocrinological outcomes. Here, we present the significance of peel-off resection of the pituitary gland in patients with FPA in whom complete extracapsular tumor removal cannot be achieved.

METHODS

We performed a retrospective review of 21 patients with FPA who underwent transsphenoidal surgery (TSS). After selective adenomectomy, peel-off resection of the adjacent pituitary gland was performed in 13 patients because complete extracapsular resection could not be achieved, while peel-off resection was not performed in the remaining 8 patients because complete extracapsular resection was accomplished. The clinical outcomes of these groups were compared. The pituitary tissues obtained by peel-off resection were pathologically examined for tumor cells.

RESULTS

Early postoperative biochemical remission was achieved in 20 patients (95.2%). Anterior pituitary functions were not aggravated postoperatively in any patient: however, transient diabetes insipidus (DI) occurred in 2 patients. There were no statistically significant differences in the clinical outcomes of the two groups. A pseudocapsule was pathologically detected in the adjacent anterior pituitary even in patients in whom no pseudocapsule was intraoperatively detected. Tumor cells were pathologically detected in 7 (58.3%) of 12 pituitary tissues examined.

CONCLUSIONS

Peel-off resection of the pituitary gland, which can remove a small tumor cell remnant in the adjacent pituitary, might maximize the effectiveness of TSS with minimal impact on postoperative pituitary function.

The optimal surgical techniques for pituitary tumors

In this paper, the currently used and well evaluated techniques for the surgery of pituitary tumors will be reviewed. Since the first surgical approaches to pituitary tumors more than 100 years have elapsed. Various surgical techniques have been developed, refined and standardized. Most of these tumors are to date treated via transsphenoidal approaches. Many pituitary adenomas, particularly, smaller, enclosed ones, can be completely excised and a selective adenomectomy is usually attempted. It leads to remission of hormonal oversecretion and also to recovery of pituitary function in many patients. The resection of pseudocapsule around the adenoma seems to improve the operative results further. Transcranial approaches, employing craniotomies, are still needed in some patients with pituitary adenomas and in many of those harbouring craniopharyngiomas. The operative techniques will be described and briefly commented. Moreover, the application and usefulness of several technical developments will be reviewed, such as the use of the endoscope, magnetic resonance imaging, fluorenscent dyes and neuronavigation. The use of the intraoperative Doppler probe, ultrasound and the value of intraoperative hormonal measurements will be briefly discussed. There is sufficient evidence that the best and optimal outcome in terms of tumor resection and correction of hormonal oversecretion as well as the lowest rate of complications are obtained in centers of excellence with sufficiently experienced, specialized surgeons and a high patient load.

Removal of the Medial Wall of the Cavernous Sinus for Functional Pituitary Adenomas: A Technical Report and Pathologic Significance

BACKGROUND

Removal of the medial wall of the cavernous sinus (MW) is challenging for neurosurgeons. We describe a practical method of endoscopic MW removal via endonasal transsphenoidal approach to minimalize intraoperative blood loss and postoperative morbidities. We also present the pathologic significance of this technique for functional pituitary adenomas (FPAs).

METHODS

We performed MW removal in patients with FPA with no well-defined pseudocapsule and a tumor in direct contact with the MW. The MW was judged to have tumor invasion based on the intraoperative appearance, and it was removed regardless of the appearance of MW involvement. Intraoperative findings and postoperative clinical, endocrinologic, and pathologic outcomes were retrospectively reviewed.

RESULTS

Fourteen patients underwent MW removal for FPA, including 12 patients with acromegaly and 2 with Cushing disease. Mean intraoperative blood loss was 170 mL (range, 32-400 mL), and none of the patients required blood transfusion. Among the 7 patients without intraoperative apparent MW involvement, 4 (57.1%) had pathologically confirmed tumor invasion into the MW (occult invasion). Biochemical remission by surgery alone was achieved in 13 patients (92.9%). Transient oculomotor palsy occurred in 1 patient (7.1%).

CONCLUSIONS

Occult tumor invasion into the MW was often detected in patients with FPA without a well-defined pseudocapsule but in direct contact with the MW. Our technique can enhance the effectiveness of surgery with minimal postoperative morbidities.

Perilesional Resection of Glioblastoma Is Independently Associated With Improved Outcomes

BACKGROUND

Resection is a critical component in the initial treatment of glioblastoma (GBM). Often GBMs are resected using an intralesional method. Circumferential perilesional resection of GBMs has been described, but with limited data.

OBJECTIVE

To conduct an observational retrospective analysis to test whether perilesional resection produced a greater extent of resection.

METHODS

We identified all patients with newly diagnosed GBM who underwent resection at our institution from June 1, 1993 to December 31, 2015. Demographics, presenting symptoms, intraoperative data, method of resection (perilesional or intralesional), volumetric imaging data, and postoperative outcomes were obtained. Complete resection (CR) was defined as 100% resection of all contrast-enhancing disease. Univariate analyses employed analysis of variance (ANOVA) and Fisher's exact test. Multivariate analyses used propensity score-weighted multivariate logistic regression.

RESULTS

Newly diagnosed GBMs were resected in 1204 patients, 436 tumors (36%) perilesionally and 766 (64%) intralesionally. Radiographic CR was achieved in 69% of cases. Multivariate analysis demonstrated that perilesional tumor resection was associated with a significantly higher rate of CR than intralesional resection (81% vs 62%, multivariate odds ratio = 2.5, 95% confidence interval: 1.8-3.4, P < .001). Among tumors in eloquent cortex, multivariate analysis showed that patients who underwent perilesional resection had a higher rate of CR (79% vs 58%, respectively, P < .001) and a lower rate of neurological complications (11% vs 20%, respectively, P = .018) than those who underwent intralesional resection.

CONCLUSION

Circumferential perilesional resection of GBM is associated with significantly higher rates of CR and lower rates of neurological complications than intralesional resection, even for tumors arising in eloquent locations. Perilesional resection, when feasible, should be considered as a preferred option.

Clinical Significance of Radical Surgery in the Treatment of Silent Corticotroph Adenoma

OBJECTIVE

Silent corticotroph adenomas (SCA) are endocrine-inactive pituitary adenomas with positive immunohistochemistry staining for adrenocorticotropic hormone (ACTH). We investigated whether SCA-associated clinical profiles were more aggressive than hormonally negative adenomas (HNA).

METHODS

Among 627 patients with pathologically proven endocrine-inactive pituitary adenomas between 2004 and 2013, positive immunohistochemistry revealed 55 SCAs and 411 HNAs. Surgical outcomes and radiological and endocrinological characteristics were compared.

RESULTS

Strong female predominance was observed in the SCA group (p<0.001). Cavernous sinus invasion was identified in 22 (40%) SCA patients and 72 (17.6%) HNA patients (p<0.001). There were no differences in ACTH or cortisol levels between the two groups. The incidence of preoperative hypopituitarism and postoperative hormonal outcome did not differ between two groups. Total resection was achieved in 35 patients (63.7%) with SCA and 332 patients (80.8%) with HNA (p=0.007). When tumors were completely removed, recurrence rates were not statistically different between two groups (p=0.60). When complete resection was not achieved, tumors regrew from these remnants in seven patients (35.0%) with SCA and 12 patients (15.2%) with HNA (p=0.05).

CONCLUSION

Total surgical resection for SCA is often challenging as these tumors frequently invade a cavernous sinus. Early remnant tumor intervention is justified, because untreated residual pituitary tumors regrow when patients were followed up for a long time. Prophylactic radiotherapy is not warranted for completely resected SCAs as tumor recurrence is uncommon.

Resection of pituitary macroadenomas via the pseudocapsule along the posterior tumor margin: a cohort study and technical note

OBJECTIVE Extracapsular resection of pituitary microadenomas improves remission rates, but the application of pseudocapsular techniques for macroadenomas has not been well described. In larger tumors, the extremely thin, compressed normal gland or its complete absence along the tumor's anterior surface limits the application of the traditional pseudocapsular technique that can be used for microadenomas. However, in the authors' experience, the interface between the pseudocapsule at the posterior margin of the adenoma and the compressed normal gland behind it is universally present, providing a surgical dissection plane. In mid-2010, the authors began using a new surgical technique to identify and use this interface for the resection of larger macroadenomas, a technique that can be used with the microscope or the endoscope. METHODS The authors performed a cohort study using prospectively collected preoperative imaging reports and operative details and retrospectively reviewed postoperative images and clinical follow-up of patients with a pituitary macroadenoma 20-40 mm in maximum diameter undergoing microscopic transsphenoidal resection. Since dissection of the tumor capsule only pertains to encapsulated tumor within the sella and not to tumor invading the cavernous sinus, assessment of tumor removal of noninvasive tumors emphasized the entire tumor, while that of invasive tumors emphasized the intrasellar component only. The incidence of residual tumor on postoperative imaging, new-onset endocrinopathy, and recovery of preoperative pituitary deficits was compared between patients who underwent surgery before (Group A) and after (Group B) implementation of the new technique. RESULTS There were 34 consecutive patients in Group A and 74 consecutive patients in Group B. Tumors in 18 (53%) Group A and 40 (54%) Group B patients had no evidence of cavernous sinus invasion on MRI. Use of the posterior pseudocapsule technique reduced the incidence of intrasellar residual tumor on postoperative MRI for tumors without cavernous sinus invasion (39% [Group A] vs 10%, p < 0.05) and in all tumors regardless of invasion (50% vs 18%, p < 0.005). The incidence of new endocrinopathy was less likely (25% vs 12%, p = 0.098) and the recovery of prior deficits more likely (13% vs 27%, p = 0.199) among patients treated using the pseudocapsule approach, although the differences are not statistically significant. CONCLUSIONS Use of the posterior pseudocapsule dissection plane can enhance the resection of pituitary macroadenomas.

The Surgical Side Effects of Pseudocapsular Resection in Nonfunctioning Pituitary Adenomas

OBJECTIVE

Pseudocapsular resection is a useful surgical technique for removing functioning pituitary adenomas; however, the significance of this procedure in nonfunctioning pituitary adenomas (NFPAs) had not been discussed in detail. We clarify the safety of pseudocapsular resection in NFPAs based on the incidence of surgical complications and evaluation of pituitary function.

METHODS

In 143 patients, initial surgery for NFPAs was performed with preoperative and postoperative pituitary provocation tests. Patients were categorized into 3 groups: total group (n = 65), in which the pseudocapsule was totally removed; partial group (n = 11), in which the pseudocapsule was partially removed; and nonremoval group (n = 67), in which the pseudocapsule was not removed or did not exist. The main outcome measure was the incidence of surgical complications and postoperative pituitary functions.

RESULTS

Intraoperative cerebrospinal fluid leakage and temporary diabetes insipidus occurred more frequently in the total group than in the nonremoval group; however, the differences were not statistically significant. There was no difference in the incidence of any other complications, including postoperative cerebrospinal fluid leakage and permanent diabetes insipidus, between the total and nonremoval groups. Postoperative anterior pituitary function improved to the same degree in both the total and the nonremoval groups. Univariate and multivariate analyses revealed that pseudocapsular resection was not a factor in the postoperative deterioration of pituitary function.

CONCLUSIONS

Pseudocapsular resection in NFPAs does not increase the risk of surgical complications or aggravate postoperative pituitary function.

Snare technique for the remodeling of the redundant arachnoid pouch to prevent cerebrospinal fluid rhinorrhea and hematoma collection during transsphenoidal surgery for suprasellar-extended pituitary tumors

OBJECTIVE Transsphenoidal surgery (TSS) is considered a most effective treatment for pituitary tumors with huge suprasellar extension. However, the chance of developing CSF leakage is relatively high, because tearing of the arachnoid membrane is common and there could be multiple tear points during the dissection of suprasellar tumors from the overlying arachnoid membrane. If there are multiple leaking points in the arachnoid membrane packing methods such as using fat or multilayered fascia graft may not be sufficient to seal off the leaking points. Moreover, the packing material may not provide sufficient tamponade to stop bleeding, and thus generates postoperative hematoma formation in the tumor resection cavity. To prevent these complications, the authors have developed a new technique for remodeling the redundant arachnoid pouch (the so-called snare technique) to reconstruct the diaphragm, seal off the CSF leak points completely, and reduce the dead space in the tumor resection cavity. METHODS In 9 patients with huge macroadenomas (> 2.5 cm in diameter) with suprasellar extension, the snare technique was used to remodel the arachnoid pouch after tumor removal via standard TSS between July 2009 and August 2014. Complications were investigated, including postoperative CSF rhinorrhea, postoperative hematoma collection, and visual compromise. RESULTS During the resection of the tumor, CSF leakage was encountered in 8 cases, all of which were sealed off using the snare technique. In 1 case without intraoperative CSF leakage, the snare technique was also applied after intentional puncturing of the arachnoid membrane to reduce the volume and tension of the arachnoid pouch. None of the 9 patients experienced postoperative CSF rhinorrhea. Lumbar CSF drainage was not required in any case. Magnetic resonance imaging studies performed 24 hours after surgery revealed a remarkable reduction in the height of the diaphragm in all cases. Visual deficits improved in all patients immediately after surgery. CONCLUSIONS Remodeling of the arachnoid pouch using the snare technique is simple and effective for completely sealing off the CSF leak point and preventing hematoma collection in the tumor resection cavity after TSS for huge pituitary tumors with suprasellar extension.

Effects of preoperative bromocriptine treatment on prolactin-secreting pituitary adenoma surgery

Pituitary adenomas are benign intracranial endocrine tumors, accounting for ~10% of intracranial tumors. The aim of the present study was to analyze the effects of preoperative treatment with bromocriptine on the surgical treatment and postoperative complications of prolactin-secreting pituitary adenomas (prolactinomas). Data from 102 patients whose prolactinomas were surgically treated between March 2006 and March 2010 were retrospectively reviewed in the present study. The study group included 54 patients who had been treated preoperatively with bromocriptine. The patients were examined by magnetic resonance imaging (MRI) of the head and coronal computed tomography (CT) scanning, after which the pathological diagnosis of prolactinoma was confirmed. A total of 64 patients underwent total resection surgery through the nose and sphenoid sinus, and 25 patients underwent subtotal resection surgery or excision of a large portion of the tumor, leaving only a small quantity of residual tumor or tumor capsule. Patients were followed up for 1-9 months using MRI and measurements of serum prolactin levels. Seven patients were lost to follow-up. The results of the present study demonstrated that patients who were treated with large doses of bromocriptine or used bromocriptine chronically suffered from an increased rate of surgical difficulties and postoperative complications, as compared with the patents who had not been pre-treated with bromocriptine. In conclusion, oral administration of bromocriptine is important in the treatment of prolactinoma tumors. However, large doses or long-term use of bromocriptine may increase difficulties in surgery or postoperative complications, and reduce its ability to treat prolactinonas, as it can lead to hardening of the tumor tissue and capsules, and aggravate pituitary stalk adhesions.

Time to Revive the Value of the Pseudocapsule in Endoscopic Endonasal Transsphenoidal Surgery for Growth Hormone Adenomas

OBJECTIVE

To investigate the role of endoscopic endonasal transsphenoidal surgery and the pseudocapsule in the treatment of growth hormone adenomas.

METHODS

The study included 43 patients (age range, 21-64 years) with growth hormone adenomas treated with an endoscopic endonasal approach. We compared the tumor characteristics and surgical outcomes of cases with (group A, 21 cases, from November 2013 to January 2015) and without (group B, 22 cases, from October 2011 to October 2013) extra-pseudocapsule resection.

RESULTS

The preoperative demographics, tumor characteristics, and surgical complications were not significantly different between groups A and B. Postoperative remission without adjuvant therapy was achieved in 18 of 21 cases (85.7%) in group A, which was significantly greater than that observed in group B (12 of 22 cases [54.4%]). In group A, the pseudocapsules were verified by endoscopy and histopathology. The pseudocapsule was removed en bloc with the whole adenoma in only 5 cases (23.8%). For the remaining 16 patients (76.2%), following extra-pseudocapsule dissection, incomplete pseudocapsule removals with intracapsule procedures were achieved.

CONCLUSIONS

The combination of extra-pseudocapsule resection and endoscopy led to a high rate of gross total tumor resection and endocrinologicl remission in acromegalic patients compared with the group with intracapsular resection. Extra-pseudocapsule resection resulted in no additional postoperative complications.