Determinants of neurosurgical outcome in pituitary tumors

The experience with transsphenoidal surgery and its importance to outcomes

PURPOSE

Surgical experience is considered paramount for excellent outcome of transsphenoidal surgery (TSS). However, objective data demonstrating the surgical success in relation to the experience of pituitary surgery units or individual experience of pituitary surgeons is sparse.

METHODS

Based on literature data, we have investigated the influence of experience with TSS for pituitary adenomas on endocrinological remission rates and on operative complications. The surgical experience was assessed by calculating the number of transsphenoidal operations per year.

RESULTS

For TSS of microprolactinomas, mean remission rates were 77% in centers with < 2 operations per year for microprolactinomas, 82% with 2-4 operations, 84% with 4-6 operations, and 91% with > 6 operations. A yearly experience with more than 10 initial operations for Cushing's disease (CD) warrants a remission rate exceeding 70%. Remission rates in CD exceeding 86% have only been reported for single surgeon series. Extraordinarily high complication rates were found in some series with < 25 yearly total operations for pituitary adenomas. Major vascular complications were less than 2% and revision rates for rhinorrhea usually < 2.5% in centers performing > 25 transsphenoidal operations per year.

CONCLUSIONS

We conclude that a center with experience of > 25 transsphenoidal operations for pituitary adenomas per year provides a high likelihood of safe TSS. Surgery for CD requires a particularly high level of practice to guarantee excellent remission rates. The endocrinologist has the unique opportunity to audit the surgical success by hormone measurement and to refer patients to neurosurgeons with proven excellence.

The utility of high-resolution intraoperative MRI in endoscopic transsphenoidal surgery for pituitary macroadenomas: early experience in the Advanced Multimodality Image Guided Operating suite

OBJECTIVE

Endoscopic skull base surgery has become increasingly popular among the skull base surgery community, with improved illumination and angled visualization potentially improving tumor resection rates. Intraoperative MRI (iMRI) is used to detect residual disease during the course of the resection. This study is an investigation of the utility of 3-T iMRI in combination with transnasal endoscopy with regard to gross-total resection (GTR) of pituitary macroadenomas.

METHODS

The authors retrospectively reviewed all endoscopic transsphenoidal operations performed in the Advanced Multimodality Image Guided Operating (AMIGO) suite from November 2011 to December 2014. Inclusion criteria were patients harboring presumed pituitary macroadenomas with optic nerve or chiasmal compression and visual loss, operated on by a single surgeon.

RESULTS

Of the 27 patients who underwent transsphenoidal resection in the AMIGO suite, 20 patients met the inclusion criteria. The endoscope alone, without the use of iMRI, would have correctly predicted extent of resection in 13 (65%) of 20 cases. Gross-total resection was achieved in 12 patients (60%) prior to MRI. Intraoperative MRI helped convert 1 STR and 4 NTRs to GTRs, increasing the number of GTRs from 12 (60%) to 16 (80%).

CONCLUSIONS

Despite advances in visualization provided by the endoscope, the incidence of residual disease can potentially place the patient at risk for additional surgery. The authors found that iMRI can be useful in detecting unexpected residual tumor. The cost-effectiveness of this tool is yet to be determined.

Evolution of minimally invasive approaches to the sella and parasellar region

Introduction Given advancements in endoscopic image quality, instrumentation, surgical navigation, skull base closure techniques, and anatomical understanding, the endonasal endoscopic approach has rapidly evolved into a widely utilized technique for removal of sellar and parasellar tumors. Although pituitary adenomas and Rathke cleft cysts constitute the majority of lesions removed via this route, craniopharyngiomas, clival chordomas, parasellar meningiomas, and other lesions are increasingly removed using this approach. Paralleling the evolution of the endonasal route to the parasellar region, the supraorbital eyebrow craniotomy has also been increasingly used as an alternative minimally invasive approach to reach this skull base region. Similar to the endonasal route, the supraorbital route has been greatly facilitated by advances in endoscopy, along with development of more refined, low-profile instrumentation and surgical navigation technology.

Objectives This review, encompassing both transcranial and transsphenoidal routes, will recount the high points and advances that have made minimally invasive approaches to the sellar region possible, the evolution of these approaches, and their relative indications and technical nuances.

Data Synthesis The literature is reviewed regarding the evolution of surgical approaches to the sellar region beginning with the earliest attempts and emphasizing technological advances, which have allowed the evolution of the modern technique. The surgical techniques for both endoscopic transsphenoidal and supraorbital approaches are described in detail. The relative indications for each approach are highlighted using case illustrations.

Conclusions Although tremendous advances have been made in transitioning toward minimally invasive transcranial and transsphenoidal approaches to the sella, further work remains to be done. Together, the endonasal endoscopic and the supraorbital endoscope-assisted approaches are complementary minimally invasive routes to the parasellar region.

Immediate and delayed postoperative morbidity in functional and non-functioning pituitary adenomas

Neurosurgery is the most widely used definite treatment for pituitary tumors, while medical treatments are a good option to improve symptoms, which tend to recur when drugs are stopped. The aim of this study was to assess postsurgical morbidity of secreting pituitary adenomas (adrenocorticotropin hormone -ACTH- and growth hormone -GH- secreting) and non-functioning (NF) adenomas, operated between January 2002 and May 2009. We retrospectively reviewed the data of 94 patients who were operated by the same neurosurgeons and compared the immediate (1st month) and delayed (1st year) complications between the three groups of adenomas. Forty had immediate post-operative complications (42% of NF, 37% of GH-secreting and 48% of ACTH-secreting adenomas). The most frequent complications were transient diabetes insipidus (23%), cerebrospinal fluid leaks (7%), sinusitis and meningitis (2%). Patients with Cushing's disease showed a tendency to have more transient diabetes insipidus and sinusitis compared to NF adenomas (P = 0.071). Ten patients had delayed complications during the first post-operative year (7% of NF, 11% of GH-secreting and 15% of ACTH-secreting), with a greater incidence of arthromyalgias and acute carpal tunnel syndrome in ACTH-secreting adenomas, compared with the other groups (P < 0.05). We conclude, that although ACTH-secreting adenomas are mostly microadenomas (78%) and affect younger patients, they are associated with a greater number of immediate and delayed complications during the first postoperative year (mainly invalidating arthromyalgias and acute carpal tunnel syndrome) compared with larger GH-secreting and NF adenomas, probably related to acute glucocorticoid deprivation after successful surgery.

Volumetric measurement for comparison of the accuracy between intraoperative CT and postoperative MR imaging in pituitary adenoma surgery

BACKGROUND AND PURPOSE

To improve the resection rate of unexpected residual pituitary tumor under image guidance, iCT provides a less time-consuming and more convenient approach of promising the safety of the trans-sphenoidal surgery. However, iCT was thought to have worse image quality than MR imaging. This study was designed to determine the predictive concordance of iCT with standard postoperative high-strength MR imaging for the detection of residual tumors.

MATERIALS AND METHODS

From February to December 2009, 33 patients with pituitary macroadenomas were enrolled in this prospective study. All patients received endoscopic trans-sphenoidal surgery for tumor removal and underwent iCT before the surgery finished. If an accessible tumor remnant was suspected and resectable, the surgery was continued. To assess the accuracy of intraoperative evaluation of tumor resection, the intraoperative findings were compared with MR imaging findings obtained 2 to 3 months after surgery by individually calculating the residual tumor volume.

RESULTS

There were no statistically significant differences in the comparison between iCT and postoperative MR imaging findings (P > .05), and the predictive rates were also high (R(2) value >0.9). The GTR rate in the case of the noninvasive and fresh cases was 89% (17/19). The overall GTR rate was 58% (19/33), the second-look rate was 21% (7/33), and only one-fourth of the recurrent cases reached GTR.

CONCLUSIONS

The extent of resection in trans-sphenoidal surgery can be reliably assessed by iCT. Compared with postoperative MR imaging findings, the findings in this study provided quantitative evidence that iCT not only holds significant promise for maximizing the extent of tumor resection but also eliminates the unnecessary blind surgical manipulation, thus increasing the safety of the procedure.

Maximizing the extent of tumor resection during transsphenoidal surgery for pituitary macroadenomas: can endoscopy replace intraoperative magnetic resonance imaging?

OBJECT

Endoscopic approaches to pituitary tumors have become an effective alternative to traditional microscopic transsphenoidal approaches. Despite a proven potential to decrease unexpected residual tumor, intraoperative MR (iMR) imaging is infrequently used even in the few operating environments in which such technology is available. Its use is prohibitive because of its cost, increased complexity, and longer operative times. The authors assessed the potential of intrasellar endoscopy to replace the need for iMR imaging without sacrificing the maximum extent of resection.

METHODS

In this retrospective study, 27 consecutive patients underwent fully endoscopic resection of pituitary macroadenomas. Intrasellar endoscopy was used to determine the presence of residual tumor within the sella turcica and tumor cavity. Intraoperative MR imaging was used to identify rates of unexpected residual tumor and the need for further tumor resection.

RESULTS

Intraoperative estimates of the extent of tumor resection were correct in 23 patients (85%). Of 4 patients with unacceptable tumor residuals, 3 underwent further tumor resection. After iMR imaging, the rate of successful completion of the planned extent of resection increased to 26 patients (96%). Rates of both endocrinopathy reversal and postoperative complications were consistent with previously published results for microscopic and endoscopic resection techniques.

CONCLUSIONS

The findings in this study provided quantitative evidence that intrasellar endoscopy has significant promise for maximizing the extent of tumor resection and is a useful adjunct to surgical approaches to pituitary tumors, particularly when iMR imaging is unavailable. A larger prospective study on the extent of resection following endoscopic transsphenoidal surgery would strengthen these findings.

Clinical predictors of advanced sellar masses

OBJECTIVE

To identify clinical variables associated with the presence of a structurally advanced sellar mass (ASM).

METHODS

We performed a retrospective study of patients referred for evaluation of suspected new pituitary disease or sellar mass to the Endocrine Oncology Unit of Mount Sinai Hospital in Toronto, Ontario, Canada. By multivariate analysis, we examined predictors of a structurally ASM (a sellar lesion with any of the following characteristics: diameter of >or=1 cm on magnetic resonance imaging [MRI], optic chiasmal compression on MRI, or clinical or biochemical evidence of hypopituitarism).

RESULTS

Data from 152 patients were analyzed. Of the 152 sellar masses, 142 (93%) were pituitary adenomas. An ASM was noted in 85 of the 152 patients (56%). In the final multivariate model, male sex (odds ratio [OR], 6.23; 95% confidence interval [CI], 2.84 to 13.56; P<0.001) and self-reported visual field defect (OR, 3.62; 95% CI, 1.07 to 12.25; P = 0.039) were significantly independently associated with the presence of an ASM. The presence of new or changed headaches also tended to be associated with an ASM (OR, 2.11; 95% CI, 0.96 to 4.64; P = 0.063). Age and self-reported galactorrhea were not independently associated with the presence of an ASM and were conditionally removed from the final model.

CONCLUSION

In patients with suspected sellar or pituitary disease, male sex and self-reported visual field defects independently predict the presence of an ASM. New or changed headaches also tend to be related to the presence of an ASM. The presence of predictors of an ASM should prompt expedited sellar MRI and biochemical evaluation.

Nonfunctioning pituitary adenoma: incidence, causes of death and quality of life in relation to pituitary function

The incidence of clinically significant, nonfunctioning pituitary adenoma, requiring surgical treatment, has not been established. According to previous studies, both surgery type and subsequent radiotherapy may have an impact on quality of life (QOL), and some studies have shown increased cardiovascular mortality in patients with pituitary disease. We studied all patients with functionless, suprasellar pituitary adenoma who were operated on during the period 1985-1996 (N = 192; transsphenoidal surgery = 160, craniotomy = 32). QOL was evaluated from Short Form 36 and Major Depression Inventory questionnaires. Causes of death were obtained from the Danish Register of Causes of Death. Incidence was 5.6/mill/year. Postoperatively, 27% of the patients had normal pituitary function and 27% were panhypopituitary. Fifty three patients had died. Death from cardiovascular, cerebrovascular and malignant diseases was not increased. Overall, QOL was not different from QOL of an age- and sex matched background population. QOL was, however, impaired in patients who had undergone craniotomy as compared to patients undergoing transsphenoidal surgery. QOL was not reduced in hypopituitary patients or in patients receiving radiotherapy.