A review of the endoscopic approach to the pituitary through the sphenoid sinus

The Significance of the Intercarotid Distances for Transsphenoidal Pituitary Surgery: A Magnetic Resonance Imaging Study

OBJECTIVE

We performed magnetic resonance imaging (MRI) to analyze the distance between the left and right internal carotid arteries (ICD) around pituitary tumors for transsphenoidal surgery (TSS).

METHODS

Measurements were performed using thin slice T2-weighted MRI, and/or time-of-flight (TOI) MR angiography imaging for 64 nonfunctioning pituitary neuroendocrine tumors (NF-pitNETs), 22 growth hormone-producing pitNETs (GH producing pitNETs), and 46 normal controls. We measured the ICD at 3 anatomic levels: at the distal dural ring (ICD-A); at the most concave point of the C4-C5 bend (ICD-B); and at the most convex point of the C4 bend (ICD-C). Additionally, we measured the sagittal distance between the tuberculum selle and the junction of the sellar floor and clivus on the midsagittal MRI (TS-C).

RESULTS

We found that ICD-B was the longest and that ICD-A was the shortest among the 3 distance parameters in all groups (P < 0.001). The comparison of the groups revealed that the NF-pitNET group had longer distances than the normal control group at all ICDs (P < 0.001). The GH producing pitNET group had longer distance than the normal control group at ICD-B (P < 0.001). Tumor volume was correlated with ICD-A and ICD-B in the NF-pitNET, and was correlated with ICD-C in the GH producing pitNET group.

CONCLUSIONS

Among the distance parameters, ICD-B is the longest, and was approximately twice the width of the TS-C. The shape of the sella is an ellipse that is widest in the lateral dimension in TSS. A horizontal based dural incision may be more rational than a conventional X-shaped dural incision.

Management of Nonfunctioning Recurrent Pituitary Adenomas

Pituitary adenomas are typically slow-growing benign tumors. However, 50% to 60% of tumors progress following subtotal resection and up to 30% recur after apparent complete resection. Options for treatment of recurrent pituitary adenomas include repeat surgical resection, radiation therapy, and systemic therapies. There is no consensus approach for the management of recurrent pituitary adenomas. This article reviews the natural history of recurrent adenomas and emerging biomarkers predictive of clinical behavior as well as the outcomes associated with the various treatment modalities for these challenging tumors, with an emphasis on the surgical treatment.

Extent of Resection, Visual, and Endocrinologic Outcomes for Endoscopic Endonasal Surgery for Recurrent Pituitary Adenomas

OBJECTIVE

To assess outcomes after endoscopic endonasal surgery for recurrent or residual pituitary adenomas.

METHODS

We retrospectively analyzed 61 patients from 2009 to 2016 who underwent endoscopic endonasal surgery for recurrent or residual pituitary adenomas after previous microscopic or endoscopic transsphenoidal operation.

RESULTS

The previous surgical approach was endoscopic endonasal in 55.7% and microscopic in 44.2% of patients. The mean preoperative maximal tumor diameter was 2.3 cm. Tumor commonly invaded the suprasellar cistern (63.9%). Gross total resection (GTR) was achieved in 31 patients (51.7%). GTR rate was 68.4% and 21.7% for Knosp grade 0-2 and grade 3-4 tumors, respectively (P < 0.001). GTR was 73.1% and 35.3% for patients with previous microscopic and endoscopic transsphenoidal surgery, respectively (P = 0.002). On multivariate analysis, smaller tumor size (odds ratio [OR], 1.1 per cm; P = 0.007), Knosp grade 0-2 (OR, 9.7; P = 0.002), and previous microscopic approach (OR, 12.7; P = 0.007) were independent predictors of GTR. Preoperative visual deficit outcome was improved in 32.5%, unchanged in 62.5%, and worse in 5.0%. New postoperative endocrinopathies included adrenal insufficiency (6.5%), hypothyroidism (8.1%), hypogonadism (6.5%), and diabetes insipidus (4.9%). Complications included postoperative cerebrospinal fluid leak (4.9%), meningitis (1.6%), medical complications (4.9%), and postoperative hematoma requiring re-exploration (3.2%).

CONCLUSIONS

The endoscopic endonasal approach provides a safe and effective option for recurrent pituitary adenomas. Smaller tumor size, absence of cavernous sinus invasion, and previous microscopic approach were independent predictors of GTR. This finding might suggest that inadequate exposure or limited viewing angle may adversely affect extent of resection in primary microscopic surgeries.

Intraoperative Neurophysiological Monitoring for Endoscopic Endonasal Approaches to the Skull Base: A Technical Guide

Intraoperative neurophysiological monitoring during endoscopic, endonasal approaches to the skull base is both feasible and safe. Numerous reports have recently emerged from the literature evaluating the efficacy of different neuromonitoring tests during endonasal procedures, making them relatively well-studied. The authors report on a comprehensive, multimodality approach to monitoring the functional integrity of at risk nervous system structures, including the cerebral cortex, brainstem, cranial nerves, corticospinal tract, corticobulbar tract, and the thalamocortical somatosensory system during endonasal surgery of the skull base. The modalities employed include electroencephalography, somatosensory evoked potentials, free-running and electrically triggered electromyography, transcranial electric motor evoked potentials, and auditory evoked potentials. Methodological considerations as well as benefits and limitations are discussed. The authors argue that, while individual modalities have their limitations, multimodality neuromonitoring provides a real-time, comprehensive assessment of nervous system function and allows for safer, more aggressive management of skull base tumors via the endonasal route.

Surgical Measurement of the Sphenoid Sinus on Sagittal Reformatted CT in the Turkish Population

OBJECTIVE

The objectives of this study were to determine sinus measurements specific for the Turkish population using CT sagittal thin-slice reconstruction images and to clarify the three-dimensional anatomical features of the sphenoid sinus, along with its surrounding structures, that are relevant to performing an endoscopic sphenoidotomy.

MATERIALS AND METHODS

Images of 300 patients (165 female, 135 male) were studied. The research was conducted on the axial plane with a 1 mm slice thickness and a 0.6 mm slice interval, and sagittal reconstruction was performed with a 0.4 mm slice interval. Measurements of the sinus were obtained, and the presence of Onodi cells was researched.

RESULTS

Line 1 was found to be significantly shorter in the Turkish patients of this study compared to studies of other populations. Lines 4 and 6 were found to be longer on the left side (Line 4 right: 18.8±3.6 mm, left: 19.3±3.4 mm, p=0.027; Line 6 right: 24.1±6.8 mm, left: 24.3±6.8 mm, p=0.008). Lines 2, 3, 4 and 6 were longer in men than in women (p<0.05).

CONCLUSION

In the Turkish population, Line 1 is shorter, so the risk of skull base perforation is greater. Lines 4 and 6 are longer on the left side; thus, choosing the left ostium in sinus dilation is safer. Because of sex differences regarding Lines 2, 3, 4 and 6, sex should be considered in sphenoid sinus procedures.

Endoscopic transnasal approach for removing pituitary tumors

To describe a series of 129 consecutive patients submitted to the resection of pituitary tumors using the endoscopic transsphenoidal approach in a public medical center.

METHOD

Retrospective analysis based on the records of patients submitted to the resection of a pituitary tumor through the endoscopic transsphenoidal approach between 2004 and 2009.

RESULTS

One hundred and twenty-nine records were analyzed. The tumor was non-secreting in 96 (74.42%) and secreting in 33 patients (22.58%). Out of the secretory tumors, the most prevalent was the growth hormone producer (7.65%), followed by the prolactinoma, (6.98%). Eleven patients developed cerebral spinal fluid (CSF) fistulas, and four of them developed meningitis. One patient died due to intracerebral hemorrhage in the postoperative period.

CONCLUSION

The endoscopic transsphenoidal approach to sellar tumors proved to be safe when the majority of the tumors were non-secreting. The most frequent complication was CSF. This technique can be done even in a public hospital with financial limits, since the health professionals are integrated.

Endoscopic Endonasal Transsphenoidal Resection for Pituitary Apoplexy during the Third Trimester of Pregnancy

Pituitary apoplexy is an uncommon phenomenon typically characterized by vascular insufficiency or acute hemorrhage into a pituitary adenoma. The overall incidence of pituitary apoplexy ranges between 1 and 25% of all pituitary adenomas. With the widespread use of MRI technology, the diagnosis of asymptomatic intratumoral hemorrhage is closer to 10%. The authors report a case of a 27-year-old female in her 36th week of pregnancy who presented with severe onset headache and acute left-sided vision loss. MRI of the brain revealed a large hemorrhagic mass occupying the sella turcica. The patient underwent an emergent endoscopic endonasal transsphenoidal resection for pituitary apoplexy. Postoperatively, the patient's neurologic deficit resolved. Minimally invasive endoscopic endonasal transsphenoidal resection of pituitary apoplexy can be safely utilized in third trimester pregnant women presenting with acute severe neurologic deficits.

Characterization of sphenoid sinuses for Sudanese population using computed tomography

The purpose of this study is to determine the anatomical features of the sphenoid sinus using computerized tomography (CT).

100 Sudanese subjects were investigated for CT sinuses; Characterization of the sphenoid sinus and seven horizontal and vertical measurements were evaluated.

Onodi cell was found in 13 subjects, 10 of them were sellar and 3 were pre-sellar. Pneumatization was of the sellar type in 85%, presellar was 15%, and no subject was chonchal.

The mean length of vertical lines from the center of sphenoid ostium to the roof and bottom were 10.6 ± 3.1 mm, 11.1 ± 3.7 mm respectively. When the sphenoid ostium was located superior to the lowest point of the sella, the line from the center of the sphenoid sinus ostium to the posterior wall of the sinus was 15.2 ± 4.2 mm and when was located inferior, the line was 26.3 ± 5.2 mm on average. The mean length from the lowest point of the sella to the anterior wall of sphenoid sinus was 16.8 ± 3.6 mm. The line from anterior wall to posterior wall of sphenoid sinus lining skull base was 10.9 ± 3.2mm mm. The maximum depth was 25.2 ± 6.9 mm and the maximum width was 18.4 ± 5.9mm. The differences in the sphenoid sinus character take place between males and females.

The study provides essential anatomical information for Sudanese subjects and its impact in the clinical surgical practice.

A novel transnasal transsphenoidal speculum: a design for both microscopic and endoscopic transsphenoidal pituitary surgery

Over the last several years minimally invasive surgical approaches to the sella turcica and parasellar regions have undergone significant change. The transsphenoidal approach to this region has evolved from a sublabial transnasal, to transnasal, to pure endonasal approaches with the increasing popularity of endoscopic over microscopic techniques. Endoscopic and microscopic techniques individually or in combination have their own unique advantages, and the preference of one over the other awaits further technological refinements and surgical experience. In parallel with this evolution in techniques for transsphenoidal surgery, the authors designed an adaptable versatile speculum for the endonasal/transnasal transsphenoidal approach to the sella turcica and parasellar regions that can be used equally effectively with a microscope or an endoscope. The development of this instrument and its unique features are described, and its initial clinical use is summarized. This transnasal transsphenoidal speculum has interchangeable blades, unique blade angulations, and independent blade opening mechanisms and allows safe, optimal exposure in all patients regardless of the size and anatomical aberrations of individual nasal and endonasal regions. An attached endoscope carrier further allows it to be used interchangeably with microscopic or endoscopic techniques without having to remove the speculum; likewise, a single surgeon can use both hands without need of an assistant. A forehead headrest component adds further stabilization. This device has been used successfully in 90 transsphenoidal procedures.

Outcomes after a purely endoscopic transsphenoidal resection of growth hormone–secreting pituitary adenomas

Object

Using strict biochemical remission criteria, the authors assessed surgical outcomes after endoscopic transsphenoidal resection of growth hormone (GH)–secreting pituitary adenomas and identified preoperative factors that significantly influence the rate of remission.

Methods

A retrospective review of a prospectively maintained database was performed. The authors reviewed cases in which an endoscopic resection of GH-secreting pituitary adenomas was performed. The cohort consisted of 26 patients who had been followed for 3–60 months (mean 24.5 months). The thresholds of an age-appropriate, normalized insulin-like growth factor–I concentration, a nadir GH level after oral glucose load of less than 1.0 μg/l, and a random GH value of less than 2.5 μg/l were required to establish biochemical cure postoperatively.

Results

Overall, in 57.7% of patients undergoing a purely endoscopic transsphenoidal pituitary adenectomy for acromegaly, an endocrinological cure was achieved. The mean clinical follow-up duration was 24.5 months. In patients with microadenomas (4 cases) the cure rate was 75%, whereas in patients harboring macroadenomas (22 cases) the cure rate was 54.5%. Cavernous sinus invasion (Knosp Grades 3 and 4) was associated with a significantly lower remission rate (p = 0.0068). Hardy Grade 3 and 4 tumors were also less likely to achieve biochemical cure (p = 0.013). The overall complication rate was 11.5% including 2 incidents of transient diabetes insipidus and 1 postoperative CSF leak, which were treated nonoperatively.

Conclusions

A purely endoscopic transsphenoidal approach to GH-secreting pituitary adenomas leads to similar outcome for noninvasive macroadenomas compared with traditional microsurgical techniques. Furthermore, this approach may often provide maximal visualization of the tumor, the pituitary gland, and the surrounding neurovascular structures.

Surgical measurement to sphenoid sinus for the Chinese in Asia based on CT using sagittal reconstruction images

The objective this study was to measure the changes of sphenoid sinusin the Chinese in AsiausingCT sagittal thin-slice reconstruction images, and to clarify the three-dimensional anatomical features of sphenoid sinus with its surrounding structures, relevant to the performing of the endoscopic sphenoidotomy. The sagittal reconstruction images were obtained from 178 CT images of 89 cases of normal adult participants (54 males and 35 females) with sphenoid sinus. We took the high-resolution axial CT images, from all the subjects, of the thickness by 0.625 mm, and reconstructed 1-mm-thick gapless sagittal CT images to measure the distance of all the sellar and pre-sellar types on the three-dimensional reconstructable sagittal plane under the bone window (4,000 at its width, and 400 at its level) in the CT images. The length of mean vertical line from the center of sphenoid ostium to the roof of sphenoid sinus of Non Onodi cell type is 10.6 ± 1.5 mm, and of Onodi cell type is 3.3 ± 1.5 mm. The length of vertical line from the center of sphenoid ostium to the lowest level of the bottom of sphenoid sinus is 12 mm ± 3.7 mm. The length of mean horizontal line from the sphenoid ostium to the posterior wall of sphenoid sinus is 18 ± 1.5 mm or 28 ± 2.5 mm. The mean horizontal line from the lowest point of the sella to the anterior wall of sphenoid sinus is 17.5 ± 1.3 mm in length. The mean horizontal distance from anterior wall to posterior wall of sphenoid sinus of Non Onodi cell type lining skull base is 10.1 ± 1.0 mm, and of Onodi cell type, is 5.2 ± 4.3 mm. The longest horizontal distance from the anterior wall to the posterior wall of sphenoid sinus is 22.0 ± 7.7 mm. The present study provides atomical information about sphenoid sinus of the Chinese in Asia with some surgical distance measured between the sphenoid ostium and the surrounding structures, which is essential to avoid the complications during surgery.

Endoscopic trans-sphenoidal surgery for pituitary tumors

Trans-sphenoidal surgery, which is the most widely used technique for the treatment of pituitary tumors, has continued to evolve by introducing new approaches and technologies, such as the direct endonasal route and the endoscope. The endonasal approach is a minimally invasive route to the sella turcica with the advantages of using a simpler and more rapid nasal dissection and eliminating the nasal and lip complications. Restricted exposure provided by the endonasal approach is overcome by combined use of an endoscope that provides a more panoramic view of the surgical field beyond the area covered by the operating microscope. An operating microscope permits binocular vision and bimanual technique, which are familiar to neurosurgeons. Neurosurgeons should exploit the advantages of both modalities for the benefit of patients. This review describes the advances in trans-sphenoidal surgery focusing on the endoscopic approach.

Der Einfluss der Navigation auf die endoskopische NNH-Chirurgie

BACKGROUND

Over the last few years, navigation systems have been used in endoscopic sinus surgery (ESS). We were interested determining whether this has repercussions on surgical procedures.

MATERIAL AND METHODS

From December 2003 to April 2006, we prospectively evaluated all navigated ESS procedures (Vector vision, Brain lab) by means of a questionnaire. Numerous data were determined including diagnosis, navigation benefit, difficulty of the operation, radiological score and complications.

RESULTS

Navigated ESS was carried out on 106 patients (54 male symbol; 52 female symbol, average age 55 years) with the following diagnoses: 59 chronic sinusitis with nasal polyposis (13 primary surgery, 46 revision surgery), 14 mucocele, 8 benign tumour, 10 malignant sinonasal tumour, and 15 other diseases. There was only a slight correlation between the difficulty of the operation and the use of navigation (r=0.51, P=0.00) and no significant correlation between the radiological score with chronic sinusitis and the use of navigation (r=0.22, P=1.23). On the other hand, we found a significant difference between the benefit of navigation using primary and revision functional ESS in cases of chronic sinusitis with nasal polyps (P=0.005). The degree of benefit of navigation for the different diagnoses was in descending order: recurrent polyposis, mucocele, osteoma, malignant tumors, polyposis (primary surgery) and inverted papilloma. Without navigation, 15 operations (14%) would not have been possible as an endonasal procedure, and 12 operations (11%) would not have been carried out thoroughly enough. In spite of navigation in three operations (3%) the endonasal approach had to be changed to a transfacial approach. Twelve slight and three serious complications (1 dura defect + pneumoencephalos, dura defect, meningitis without CSF leak) occurred.

CONCLUSIONS

Navigation exerts a substantial influence on the execution of the ESS by clearly extending its possibilities.