The use of the rigid endoscope in trans-sphenoidal pituitary surgery

Comparison of the endoscopic endonasal to microscopic sublabial transsphenoidal approach in a case series of pituitary macroadenomas

For a number of years, the microscopic sublabial transsphenoidal (MST) approach was considered the gold standard approach for the treatment of pituitary macroadenomas. Nonetheless, the trend is currently shifting away from the MST to the endonasal transsphenoidal (EET) approach. The aim of the present study was to examine the post-operative outcomes of the first cases operated by a team of two young surgeons using the EET approach, compared to the cases operated by a team of senior neurosurgeons with extensive experience with the MST approach. For this purpose, data from 20 patients with pituitary adenoma were retrospectively collected from a single center who were operated by the current and previous pituitary-surgery teams. All the patients who presented with visual impairment in the EET group recovered completely (5/5), whereas 4/5 patients in the MST group recovered completely. Primary hospitalization duration was similar in the two groups. Gross tumor removal was achieved in 90% of patients in the EET group compared to 70% of the patients operated with the MST technique. Intraoperative complications were comparable between the two groups. The first cases operated at the center with EET proved to have better visual outcomes and a larger tumor removal when compared to the MST group. A greater experience in using this technique could exponentiate the differences in the post-operative outcomes, such as a lower hospitalization duration and fewer intraoperative complications. On the whole, colleagues who have yet to familiarize themselves with the EET approach could perhaps be encouraged to learn to utilize this technique, provided that their center is staffed with an experienced team of skull base surgeons to intervene in an intraoperative complication.

Superiority of endoscopic transsphenoidal pituitary surgery to microscopic transseptal pituitary surgery for treatment of Cushing's disease

OBJECTIVE

This study aims to compare the efficacy and safety of endoscopic transsphenoidal pituitary surgery and microscopic transseptal pituitary surgery in the treatment of Cushing's disease (CD).

METHODS

A total of 46 patients with CD were randomized into endoscopic group and microscopic group, with 23 cases in each group. The endoscopic group received the endoscopic transsphenoidal pituitary surgery, and the microscopic group received the microscopic transseptal pituitary surgery. The retrospective data, surgical outcomes, surgical cure rates, and complications in two groups were compared.

RESULTS

Compared with microscopic group, the operative time was significantly shorter (p<0.05), the estimated blood loss was significantly less (p<0.05), and the hospital stay was significantly shorter (p<0.05) in endoscopic group. The surgical cure rate in endoscopic and microscopic groups was 69.56% and 60.86%, respectively, with no significant difference between the two groups (p>0.05). The incidence of complications in endoscopic group was significantly lower than that in microscopic group (p<0.01).

CONCLUSIONS

For the treatment of CD, the efficacy of endoscopic transsphenoidal pituitary surgery is basically the same as that of traditional microscopic transseptal pituitary surgery. However, the endoscopic surgery can further shorten the operative time, reduce the estimated blood loss, shorten the hospital stay, and reduce the complications.

Management of Giant Pituitary Adenomas: Role and Outcome of the Endoscopic Endonasal Surgical Approach

Giant adenomas represent a significant surgical challenge. Although traditionally several transcranial and transsphenoidal microscopic approaches have had a central role in their management, in the last 2 decades here have been increasing reports of the endoscopic endonasal approach for giant adenomas, citing its improved resection rates and lower complication profile. However, its role as the preferred approach has not been fully established and there is currently a paucity of evidence-based recommendations available in the literature. This article reviews the current literature and attempts to define the role and outcomes of the endoscopic endonasal surgical approach for giant pituitary adenomas.

Complications associated with microscopic and endoscopic transsphenoidal pituitary surgery: experience of 1153 consecutive cases treated at a single tertiary care pituitary center

OBJECTIVE

Pituitary adenomas (PAs) are benign neoplasms that are frequently encountered during workup for endocrinopathy, headache, or visual loss. Transsphenoidal surgery remains the first-line approach for PA resection. The authors retrospectively assessed complication rates associated with transsphenoidal PA resection from an institutional database.

METHODS

A retrospective analysis of 1153 consecutive transsphenoidal pituitary adenoma resections performed at the Keck Hospital of USC between November 1992 and March 2017 was conducted. Microscopic transsphenoidal resection was performed in 85.3% of cases, and endoscopic transsphenoidal resection was performed in 14.7%. Analysis of perioperative complications and patient and tumor risk factors was conducted.

RESULTS

The overall median hospital stay was 3 days. There was 1 perioperative death (0.1%). Surgical complications included postoperative cerebrospinal fluid leak (2.6%), epistaxis (1.1%), postoperative hematoma (1.1%), meningitis (1.0%), cranial nerve paresis (0.8%), hydrocephalus (0.8%), vision loss (0.6%), stroke (0.3%), abdominal hematoma or infection (0.2%), carotid artery injury (0.1%), and vegetative state (0.2%). Perioperative medical complications included bacteremia/sepsis (0.5%), pneumonia (0.3%), myocardial infarction (0.3%), and deep venous thrombosis/pulmonary embolism (0.1%). Endocrine complications were the most frequent, including transient diabetes insipidus (4.3%), symptomatic hyponatremia (4.2%), new hypopituitarism (any axis) (3.6%), permanent diabetes insipidus (0.3%), and adrenal insufficiency (0.2%). There were no significant differences between microscopic and endoscopic approaches with regard to surgical complications (6.4% vs 8.8%, p = 0.247) or endocrine complications (11.4 vs 11.8%, p = 0.888). Risk factors for surgical complications included prior transsphenoidal surgery (11.4% vs 6.8%, p = 0.025), preoperative vision loss (10.3% vs 6.8%, p = 0.002), and presence of PA invasion on MRI (8.5% vs 4.4%, p = 0.007).

CONCLUSIONS

In this single tertiary center study assessing complications associated with transsphenoidal PA resection, the rate of death or major disability was 0.26%. Risk factors for complications included prior surgical treatment and PA invasion. No differences in complication rates between endoscopic and microscopic surgery were observed. When performed at experienced pituitary centers, transsphenoidal surgery for PAs may be performed with a high degree of safety.

Sellar Reconstruction: Is it Necessary?

Background

Sellar reconstruction is practiced routinely during the transsphenoidal approach to pituitary tumor resection. This practice exposes the patient to risks of donor site complications and may interfere with measuring postoperative tumor reduction. We propose that it is not a necessary component of transsphenoidal pituitary surgery in the absence of intraoperative cerebrospinal fluid (CSF) leak.

Methods

A retrospective chart review of 45 cases of minimally invasive pituitary surgery were reviewed. Twenty-eight cases were identified with no sellar reconstruction being performed. Age, sex, revision surgery, postoperative CSF leak, days with lumbar drain, meningitis, ophthalmoplegia, visual acuity loss, postoperative epistaxis, diabetes insipidus, development of empty sella syndrome, and length of stay were investigated in these cases.

Results

Twenty-three cases were the primary procedure and five cases were revision surgery. Complication rates were low and compared favorably with those reported in the literature. Five cases of transient diabetes insipidus occurred. There was one postoperative CSF leak that required 4 days with a lumbar drain. No cases of empty sella syndrome developed. There were no cases of meningitis. The average length of stay was 2.9 days.

Conclusion

Sellar reconstruction during transsphenoidal approach to pituitary tumor resection is not required for patients without evidence of an intraoperative CSF leak. This practice exposes the patient to the risks of donor site complications without reducing the rate of postoperative complications.

Endoscopic Transnasal Pituitary Surgery: Report on 180 Cases

The endoscopic transnasal approach is an evolving technique for treating lesions in the sella turcica. Since this method was introduced at our institution 4 years ago, the majority of transsphenoidal procedures are performed with it. The records of all patients having endoscopic transnasal hypophysectomy at the Mayo Clinic during the last 4 years were reviewed retrospectively. The criteria analyzed were safety, functional and cosmetic outcome, and complications. During the 4-year period, the operative procedure was modified to improve operative exposure and safety. The results of our review showed a significant decrease in length of hospital stay, reduced operative time, reduced need for nasal packing, and elimination of a sublabial incision. The complication rate was equivalent to that reported for the traditional transseptal transsphenoidal approach. As the neurosurgeons at our institution gained experience with this approach, an increasing number of pituitary microadenomas were resected safely and successfully. In addition, because of the limited septal dissection, this approach is particularly helpful for revision operations. This approach also can be used for the full range of pituitary lesions and in conjunction with adjunctive techniques, including frontal craniotomy and -knife irradiation. Currently, the endoscopic transsphenoidal approach is the method preferred for surgically treating pituitary lesions in adults at our institution.

The Learning Curve in Minimally Invasive Pituitary Surgery

Background

Minimally invasive pituitary surgery (MIPS) is performed via an endoscopic transnasal transsphenoidal approach. This provides excellent illumination, visualization, and magnification of the operative field, in addition to avoiding complications associated with other approaches. In this study we examined the first 45 cases of MIPS to determine if a learning curve exists for this technique.

Methods

A retrospective chart review was performed of the first 45 cases of MIPS at a major academic medical center. Cases were divided into three groups of 15 patients each. Group characteristics including age, sex, and revision surgery were compared. Complication rates investigated included death, intracerebral hemorrhage, intraoperative cerebrospinal fluid leak, postoperative cerebrospinal fluid leak, use of lumbar drain, meningitis, postoperative epistaxis, ophthalmoplegia, visual impairment, and diabetes insipidus. Other factors examined included intraoperative blood loss, length of stay, and tumor histology. One way analysis of variance statistical analysis was used to determine the significance of differences between groups.

Results

Groups were comparable in respect to characteristics studied. Statistically significant (p < 0.05) differences in complication rates and other factors between groups were not shown. Complication rates are low.

Conclusion

This study does not establish a learning curve for our first 45 cases of MIPS. This finding supports the concept that an otolaryngology/neurosurgery team skilled in endoscopic techniques and pituitary surgery can safely transition from open approaches to an endoscopic approach in pituitary surgery.

The endoscopic surgical resection of intrasellar lesions conserves the hormonal function: a negative correlation to the microsurgical technique

BACKGROUND

The endonasal endoscopic approach is still currently under investigation for sellar tumor surgery: a higher resection rate is to be expected and complications should be minimized. The authors report their surgical results of endonasal endoscopic neurosurgery with special focus on postoperative hypopituitarism in comparison to microsurgical procedures.

METHODS

Sixty patients received endoscopic endonasal transsphenoidal procedures for sellar pathologies. All patients were followed up prospectively. A second group of 60 patients received microsurgical transsphenoidal procedures for sellar pathologies in our neurosurgical department before and were prospectively followed until now. Special attention was paid to hormonal insufficiency and medical substitution.

RESULTS

Sixty-eight percent (41 of 60) of the patients who underwent microsurgical procedures showed a new persisting pituitary insufficiency postoperatively. Twenty-three patients (55.5%) were substituted with thyroxine, hydrocortisone and sexual hormones and one patient (2.5%) also with ADH cause of global pituitary insufficiency. In 19 cases without any hormonal insufficiency after microsurgical procedures nine patients (47%) showed remnant tumor in follow-up MRI. The patients who underwent endoscopic procedures for pituitary adenomas revealed significant (P<0.01) less new persistent hormonal insufficiency with 13% of all cases (8/60). Five patients (62.5%) were substituted with thyroxine and hydrocortisone, two patients (25%) substituted with thyroxine, hydrocortisone and sexual hormones and one patient also with ADH because of global pituitary insufficiency. Thereby, in follow-up MRI and hormonal testing, radical tumor resection was detected in 92% in the endoscopic group.

CONCLUSIONS

This study seems to indicate that a better intraoperative identification and preservation of pituitary gland is possible in endoscopic transsphenoidal surgery with consecutive lower postoperative hypopituitarism rate.

Efficacy of Microsurgical Sublabial Approach (MSA) Versus Endoscopic Endonasal Approach (EEA) for the Treatment of Pituitary Adenomas Based on Radiological and Hormonal Outcome

BACKGROUND

The purpose of this study was to compare the surgical efficacy of the microsurgical sublabial approach (MSA) versus the endoscopic endonasal approach (EEA) for the treatment of pituitary adenomas, based on short-term (12 months) radiological and endocrinological follow-up.

METHODS

One hundred and fourteen patients affected by pituitary adenoma were enrolled at our Unit between January 2007 and February 2012; 72 were treated with MSA, and 42 with EEA. The preoperative parameters considered were: type of lesion (secreting or nonsecreting), lesion size, presence of intralesional hemorrhage, lesion perimeter (nodular vs. uniform), intrasellar vs. suprasellar, involvement of cavernous sinus, and osteodural infiltration. Hormonal assays and magnetic resonance imaging (MRI) scans were performed at 12 months after the surgical procedure.

RESULTS

Univariate analysis of the data documented a statistically significant difference in favor of MSA for the subgroups of secreting adenomas (90.9 % vs. nonsecreting 48.3 %), microadenomas (100 % vs. macroadenomas 57.1 %), adenomas without osteodural infiltration (87.5 % vs. 55.5 % with the infiltration) or those without intralesional hemorrhage (75 % vs. 45.9 % with the hemorrhage), and growth hormone (GH) adenomas (88.8 % vs. 43.7 %). Multivariate analysis confirmed the greater effectiveness of MSA for the treatment of micro-secreting adenomas.

CONCLUSIONS

Recent advances in the EEA for treating pituitary adenomas could lead to this modality replacing the microsurgical technique. In our experience the MSA allowed us to achieve better results in the treatment of microadenomas.

Limiti e complicanze dell'endoscopia transfenoidale

L'approccio endoscopico alla regione sellare appare la metodica più indicata per ottenere sia una migliore visualizzazione delle strutture endosellari sia un adeguato funzionamento del sistema di ventilazione dei seni paranasali.

Nella nostra esperienza, su 102 casi trattati c/o le Cliniche Neurochirurgica ed Otorinolaringoiatrica del Policlinico San Matteo, Università di Pavia non si sono evidenziate complicanze maggiori, mentre l'incidenza delle complicanze minori è stata del 5,4%.

In questo gruppo abbiamo riscontrato: lesioni della lamina papiracea (0,9%), sinechie (3,6%) e sovrainfezioni (0,9%), tutte risolte con semplice trattamento medico.

L'affinamento delle nuove tecnologie con i sistemi motorizzati sia di lavaggio che di asportazione tissutale e la possibile evoluzione di una visione 3D associati all'allenamento specifico con miglioramento della manualità chirurgica esaltano le caratteristiche di mini-invasività di questa tecnica proponendola come la miglior via per raggiungere la cavità sellare nel rispetto delle funzioni vitali dei seni paranasali quali il trasporto mucociliare e la ventilazione rinosinusale.

Endoscopic Versus Microscopic Transsphenoidal Approach for Pituitary Adenomas: Comparison of Outcomes During the Transition of Methods of a Single Surgeon

OBJECTIVE

The transition from microscopic to fully endoscopic transsphenoidal surgery requires a surgeon to assess how the change in technique will affect the extent of tumor resection (EOR), outcomes, and complications. We compared a single surgeon's experience transitioning from one technique to the other and examined the operative outcomes and EOR between microscopic versus endoscopic transsphenoidal surgery.

METHODS

Retrospective data analysis of adult patients who were treated surgically for a pituitary adenoma between August 2005 and May 2015 by a single neurosurgeon, who was originally trained and practiced in the microscopic transsphenoidal approach. Patient demographics, perioperative conditions, tumor characteristics, operative times, volumetric EOR, postoperative outcome, and the endoscopic learning curve were evaluated.

RESULTS

One hundred and nine patients underwent microscopic transsphenoidal surgery and 275 patients underwent a fully endoscopic approach. The patient characteristics were similar in the 2 groups. Operative room time was significantly shorter in the endoscopic group than in the microscopic group (180.2 vs. 215.6 minutes; P < 0.001). The endoscopic and microscopic groups had similar volumetric EOR (85.1% vs. 82.8%; P = 0.371) as well as residual tumor volume (1.06 cm³ vs. 1.15 cm³; P = 0.765). The mean length of hospital stay was 2.4 days in the endoscopic group and 3.2 days in the microscopic group (P = 0.03).

CONCLUSIONS

During the transition from the microscopic to the endoscopic approach, similar surgical outcomes and EOR were achieved in the 2 cohorts. In our experience, the endoscopic approach offers the advantage of shorter operative times and lengths of hospital stays after the surgeon has developed more experience with the technique.

Role of Endoscopic Skull Base and Keyhole Surgery for Pituitary and Parasellar Tumors Impacting Vision

Significant advances over the last 2 decades in imaging technology, instrumentation, anatomical knowledge, and reconstructive techniques have resulted in the endonasal endoscopic approach becoming an integral part of modern skull base surgery. With growing use and greater experience, surgical outcomes continue to incrementally improve across many skull base pathologies, including those tumors that impact vision and ocular motility. The importance of the learning curve and use of a multi-disciplinary approach is critical to maximizing success, minimizing complications, and enhancing quality of life in these patients. Realizing the limits of the endonasal route and reasonable use of transcranial approaches such as the supraorbital eyebrow craniotomy, it may br appropriate to consider nonsurgical therapy including various forms of radiotherapy [corrected] and medical treatment options.

Serial Re-Expansion of Pituitary Gland Is Associated with Endocrinologic Recovery

BACKGROUND

Minimizing pituitary dysfunction by preservation of the normal pituitary gland has a significant clinical impact on patient outcome after pituitary surgery. This study aimed to determine whether re-expansion of the healthy gland after surgery was related to endocrinologic outcome.

METHODS

From January 2012 to July 2014, 112 patients were eligible for this retrospective study. Magnetic resonance imaging with dynamic contrast enhancement done2 days and 3 months before and after surgery was evaluated to assess the tumor and normal pituitary gland. We assessed the size of the pituitary gland and evaluated the relationship with endocrinologic outcome.

RESULTS

The mean preoperative size of the gland was 3.86 mm, within 2 days after surgery it was 5.50 mm and 3 months after surgery it was 7.17 mm. Preoperatively patients were grouped based on their requirement of hormone replacement. Patients who required hormone replacement therapy before surgery and did not recover from hormonal insufficiency were classified as group 1 (26 patients), those who recovered from preoperative hormonal insufficiency and discontinued hormone replacement after surgery were classified as group 2 (17 patients), and those who showed hormonally normal status and did not need hormone replacement before and after surgery were in group 3 (68 patients). In group 1, the size of the gland expanded 1.24 times within postoperative 2 days but had no increase after 3 months (1.25 mm) (P = 0.716). Group 2 showed a 1.30 times larger gland within postoperative 2 days and 2.37 times at 3 months follow-up (P = 0.001). Group 3 showed 1.62 times larger gland at postoperative day 2 and 2.1 times larger at the 3-month follow-up.

CONCLUSIONS

Serial re-expansion of the healthy pituitary gland at the 3-month follow-up magnetic resonance imaging can predict the endocrinologic recovery.

The expanding role of the endonasal endoscopic approach in pituitary and skull base surgery: A 2014 perspective

BACKGROUND

The past two decades have been the setting for remarkable advancement in endonasal endoscopic neurosurgery. Refinements in camera definition, surgical instrumentation, navigation, and surgical technique, including the dual surgeon team, have facilitated purely endonasal endoscopic approaches to the majority of the midline skull base that were previously difficult to access through the transsphenoidal microscopic approach.

METHODS

This review article looks at many of the articles from 2011 to 2014 citing endonasal endoscopic surgery with regard to approaches and reconstructive techniques, pathologies treated and outcomes, and new technologies under consideration.

RESULTS

Refinements in approach and closure techniques have reduced the risk of cerebrospinal fluid leak and infection. This has allowed surgeons to more aggressively treat a variety of pathologies. Four main pathologies with outcomes after treatment were identified for discussion: pituitary adenomas, craniopharyngiomas, anterior skull base meningiomas, and chordomas. Within all four of these tumor types, articles have demonstrated the efficacy, and in certain cases, the advantages over more traditional microscope-based techniques, of the endonasal endoscopic technique.

CONCLUSIONS

The endonasal endoscopic approach is a necessary tool in the modern skull base surgeon's armamentarium. Its efficacy for treatment of a wide variety of skull base pathologies has been repeatedly demonstrated. In the experienced surgeon's hands, this technique may offer the advantage of greater tumor removal with reduced overall complications over traditional craniotomies for select tumor pathologies centered near the midline skull base.

Endoscopic anatomy of the skull base explored through the nose

OBJECTIVE

Different surgical approaches have been used over the years in order to access skull base. The endoscopic endonasal approach represents a direct and minimally invasive approach to the suprasellar, retrosellar, and retroclival space, with the advantage of avoid brain retraction and visualize safely and effectively the surgical target. The present contribution aims to provide anatomical details of the skull base as seen from below (i.e., via an endoscopic endonasal approach).

METHODS

Five human cadaver heads were dissected. The anatomical neurovascular structures within the skull base were visualized and carefully described from an endoscopic endonasal view. The advantages and limitations of the endoscopic endonasal route were discussed as well.

RESULTS

The entire skull base region, as seen from the endoscopic endonasal viewpoint, has been divided in 4 main regions: anterior skull base, middle skull base, posterior skull base and parasellar area.

CONCLUSION

The development of endoscopic techniques has opened different perspectives over the skull base surgery. Endonasal surgery provides access to a wide range of skull base lesions via a natural surgical corridor (i.e., the nasal cavities).

Invasion of the cavernous sinus space in pituitary adenomas: endoscopic verification and its correlation with an MRI-based classification

OBJECT An important prognostic factor for the surgical outcome and recurrence of a pituitary adenoma is its invasiveness into parasellar tissue, particularly into the space of the cavernous sinus (CS). The aims of this study were to reevaluate the existing parasellar classifications using an endoscopic technique and to evaluate the clinical and radiological outcomes associated with each grade. METHODS The authors investigated 137 pituitary macroadenomas classified radiologically at least on one side as Grade 1 or higher (parasellar extension) and correlated the surgical findings using an endoscopic technique, with special reference to the invasiveness of the tumor into the CS. In each case, postoperative MRI was performed to evaluate the gross-total resection (GTR) rate and the rate of endocrinological remission (ER) in functioning adenomas. RESULTS The authors found a 16% rate of CS invasion during surgery for these macroadenomas. Adenomas radiologically classified as Grade 1 were found to be invasive in 1.5%, and the GTR/ER rate was 83%/88%. For Grade 2 adenomas, the rate of invasion was 9.9%, and the GTR/ER rate was 71%/60%. For Grade 3 adenomas, the rate of invasion was 37.9%, and the GTR/ER rate was 75%/33%. When the superior compartment of the CS (Grade 3A) was involved, the authors found a rate of invasion that was lower (p < 0.001) than that when the inferior compartment was involved (Grade 3B). The rate of invasion in Grade 3A adenomas was 26.5% with a GTR/ER rate of 85%/67%, whereas for Grade 3B adenomas, the rate of surgically observed invasion was 70.6% with a GTR/ER rate of 64%/0%. All of the Grade 4 adenomas were invasive, and the GTR/ER rate was 0%. A comparison of microscopic and endoscopic techniques revealed no difference in adenomas with Grade 1 or 4 parasellar extension. In Grade 2 adenomas, however, the CS was found by the endoscopic technique to be invaded in 9.9% and by microscopic evaluation to be invaded in 88% (p < 0.001); in Grade 3 adenomas, the difference was 37.9% versus 86%, respectively (p = 0.002). Grade 4 adenomas had a statistically significant lower rate of GTR than those of all the other grades. In case of ER only, Grade 1 adenomas had a statistically significant higher rate of remission than did Grade 3B and Grade 4 adenomas. CONCLUSIONS The proposed classification proved that with increasing grades, the likelihood of surgically observed invasion rises and the chance of GTR and ER decreases. The direct endoscopic view confirmed the low rate of invasion of Grade 1 adenomas but showed significantly lower rates of invasion in Grade 2 and 3 adenomas than those previously found using the microscopic technique. In cases in which the intracavernous internal carotid artery was encased (Grade 4), all the adenomas were invasive and the GTR/ER rate was 0%/0%. The authors suggest the addition of Grades 3A and 3B to distinguish the strikingly different outcomes of adenomas invading the superior CS compartments and those invading the inferior CS compartments.

Retrospective analysis of a concurrent series of microscopic versus endoscopic transsphenoidal surgeries for Knosp Grades 0-2 nonfunctioning pituitary macroadenomas at a single institution

OBJECT

The object of this study was to compare surgical outcomes and complications in a contemporaneous series of patients undergoing either microscopic or endoscopic transsphenoidal surgery for nonfunctioning pituitary macroadenomas without imaging evidence of cavernous sinus invasion.

METHODS

This is a retrospective analysis of a prospectively collected database from a single institution. Data were collected from patients whose surgery had occurred in the period from June 2010 to January 2013. Patients who underwent microscopic or endoscopic surgery for Knosp Grade 0, 1, or 2 nonfunctioning pituitary macroadenomas were included in the study. Patients who had clinically secreting or Knosp Grade 3 or 4 tumors and patients who were undergoing revision surgery were excluded from analysis. Eligible patient records were analyzed for outcomes and complications. Statistical analyses were performed on tumor volume, intraoperative factors, postoperative complications, and degree of resection on 1-year postoperative MRI. The results were used to compare the outcomes after microscopic and endoscopic approaches.

RESULTS

Forty-three patients underwent microscopic transsphenoidal surgery, and 56 underwent endoscopic transsphenoidal surgery. There were no statistical differences in the intraoperative extent of resection or endocrinological complications. There were significantly more intraoperative CSF leaks in the endoscopic group (58% vs 16%); however, there was no difference in the incidence of postoperative CSF rhinorrhea (12% microscopic vs 7% endoscopic). Length of hospitalization was significantly shorter in patients undergoing an endoscopic approach (3.0 days vs 2.4 days). Two-month follow-up imaging was available in 95% of patients, and 75% of patients had 1-year follow-up imaging. At 2 months postprocedure, there was no evidence of residual tumor in 79% (31 of 39) and 85% (47 of 55) of patients in the microscopic and endoscopic groups, respectively. At 1 year postprocedure, 83% (25 of 30) of patients in the microscopic group had no evidence of residual tumor and 82% (36 of 44) of those in the endoscopic group had no evidence of residual tumor.

CONCLUSIONS

The microscopic and endoscopic techniques provide similar outcomes in the surgical treatment of Knosp Grades 0-2 nonfunctioning pituitary macroadenomas.

Endoscopic endonasal transsphenoidal approach for sellar tumors beyond the sellar turcica

CONCLUSIONS

The endoscopic endonasal transsphenoidal approach can be a choice for sellar tumors beyond the sellar turcica, but it is necessary to make the choice carefully because of the severe surgical risks.

OBJECTIVES

To summarize our experience of removal of sellar tumors beyond the sellar turcica via the endoscopic endonasal transsphenoidal approach and to evaluate the surgical efficacy and complications.

METHODS

Between January 2007 and January 2012, 30 patients with sellar tumors beyond the sellar turcica underwent surgery using the endoscopic endonasal transsphenoidal approach.

RESULTS

Postoperative pathological examination demonstrated that pituitary adenoma occurred in 22 patients, craniopharyngioma in 5, and meningioma in 3. Total removal was achieved in 21 patients (70.0%) and subtotal removal was achieved in 8 patients (26.7%). After the surgery, cerebrospinal fluid leakage occurred in 3 patients, temporary diabetes insipidus occurred in 25 patients and persistent diabetes insipidus in 4 patients, intracranial infection occurred in 1 patient, frontal subdural effusion occurred in 1 patient, sinusitis occurred in 2 patients, epistaxis occurred in 3 patients, and 1 patient with a huge pituitary adenoma died of hypothalamic failure related to the operation.

Volumetric classification of pituitary macroadenomas predicts outcome and morbidity following endoscopic endonasal transsphenoidal surgery

Endoscopy in combination with extended approaches allow for resection of large pituitary adenomas via a transsphenoidal route. The objective of the current study was to determine a volumetric threshold for lesions with high perioperative morbidity and high rate of subtotal resection following endonasal endoscopic surgery. Thus, we analyzed a prospectively collected database of 71 patients who underwent endoscopic transsphenoidal approaches for macroadenomas (diameter >1 cm). Extend of resection (EOR) was calculated based on volumetric analysis of pre-and post-operative contrast-enhanced MRI. Average EOR was 97.8% and a gross total resection (GTR) was achieved in 76.1% of all patients. GTR was accomplished in 92.0% versus 38.1% of adenomas either without or with CS invasion, respectively. Likewise, GTR was accomplished in 90.2% versus 40.0% of lesions less than or greater then 10 cm(3) respectively. However, even if only subtotal resection was achieved, 90.3% of tumor volume was removed. At 17 months follow-up, visual field defects improved in 80.8% of patients. Complications included permanent diabetes insipidus (5 patients), panhypopituitarism (4 patients), injury to the ophthalmic artery (1 patient) and CSF leak (1 patient). On multivariate logistic regression, two factors negatively predicted GTR: invasion of the CS and volume greater than 10 cm(3). A 10 cm(3) threshold was a stronger predictor of EOR and complication risk than diameter-based measurements. A volume greater than 10 cm(3) and CS invasion may help to identify pituitary lesions associated with a higher likelihood of subtotal resection and post-operative morbidity.

Endoscopic endonasal extended transsphenoidal removal of tuberculum sellae meningioma (TSM): an experience of six cases

AIMS

Tuberculum sellae meningiomas (TSMs) are usually removed through a transcranial approach. Recently, the sublabial transsphenoidal microscopic approach has been used to remove such tumours. More recently, endonasal extended transsphenoidal approach is getting popular for removal of tuberculum sellae meningioma. Here, we describe our initial experience of endonasal extended transsphenoidal approach for removal of suprasellar meningiomas in six consecutive cases.

MATERIALS AND METHOD

Six patients (four female and two male) who presented for headache and visual loss were investigated with MRI of brain that showed tuberculum sellae meningioma compressing visual apparatus. Average size was 3 × 3 cm in three cases and 4 × 4 cm in rest of the three. All patients underwent endoscopic endonasal extended transsphenoidal tumour removal, but in two patients with large tumour, microscopic assistance was needed. Complete tumour removal was done in all cases except one case where perforators seemed to be encased by the tumour and resulted in incomplete removal. The surgical dural and bony defects were repaired in all patients with thigh fat graft. Nasal packing was not used, but inflated balloon of Foley's catheter was used to keep fat in position.

RESULT

There was mild postoperative cerebrospinal fluid (CSF) leakage in one patient on the fourth postoperative day after removal of lumbar CSF drain and stopped spontaneously on the seventh postoperative day. There were no postoperative CSF leaks or meningitis in the rest of the cases. In one patient, there was visual deterioration due to pressure on optic nerve by grafted fat and improved within 4 weeks. At 4 months after surgery, three patients had normal vision, two patients improved vision comparing with that of preoperative state but with some persisting deficit; one patient had static vision, no new endocrinopathy and no residual tumour on MRI in five cases but residual tumour in remaining case was static at the end of the ninth month.

CONCLUSION

The endoscopic endonasal extended transsphenoidal approach appears to be an effective minimally invasive method for removing relatively small to medium tuberculum sellae meningiomas. With more experience of the surgeon, larger tuberculum sellae meningioma may be removed by purely endoscopic techniques in near future.

Endoscopic Trans-Nasal Trans-Sphenoidal (TNTS) Approach For Pituitary Adenomas: Our Experience

Advances in optics, miniaturization, and endoscopic instrumentation have revolutionized surgery in the past decade. Current progress in the field of endoscopy promises to further this evolution: endoscopic telescopes and instruments have improved upon the optical and technical limitations of the microscope, and require an even less invasive approach to the sella. Pituitary surgery is traditionally within the realm of the neurosurgeon. However, since the reintroduction of the transseptal transsphenoidal approach and endoscopic transnasal transsphenoidal approach to the sella turcica for resection of pituitary adenoma, otolaryngologists have been active partners in the surgical management of these patients. Otolaryngologists have lent their expertise in nasal and sinus surgery, assisting the neurosurgeon with the operation. The otolaryngologist has the advantage of familiarity with the techniques and instruments used to gain exposure of the sella turcica by transnasal approach. Hence, the otolaryngologist provides the exposure, and the neurosurgeon resects the tumour. Such collaboration has resulted in decreased rates of complication and morbidity. We hereby discuss our experience of treating 54 cases of pituitary tumour by endoscopic transnasal approach at our hospital.

Comparison of the exposure obtained by endoscope and microscope in the extended trans-sphenoidal approach

OBJECTIVE

Trans-sphenoidal surgery is often combined with other approaches for the treatment of middle cranial base tumors. By combining a maxillotomy with trans-sphenoidal approach, significantly wider exposure to these regions is gained. However, endoscope-assisted techniques have also been used for sellar and parasellar and upper clival regions.

METHODS

An extended trans-sphenoidal approach was performed on 10 cadaver heads using the operating microscope and was repeated with a 0-degree endoscope. The mean horizontal and vertical distances were measured and pictured for each technique, and both distances were compared using a parametric paired Student's t-test.

RESULTS

The mean horizontal distances in the 10 specimens were 19.5 +/- 1.8 mm by microscope and 27.5 +/- 2.2 mm by endoscope, and the mean vertical distances were 25.8 +/- 1.9 mm by the microscope and 34.5 +/- 3.5 mm by the endoscope.

CONCLUSION

The aim of this study was to quantify the amount of exposure obtained with an extended trans-sphenoidal approach and to compare both endoscopic and microscopic techniques. Using the endoscope in conjunction with the operating microscope may provide additional exposure and better access in skull base surgery.

The use of a three-dimensional novel computer-based model for analysis of the endonasal endoscopic approach to the midline skull base

OBJECTIVES

To apply a three-dimensional geometric model to various endoscopic endonasal approaches to analyze the bony anatomy of this area, quantify preoperatively bone removal, and optimize surgical planning.

METHODS

Investigators dissected 18 human cadaveric heads at the Laboratory of Surgical NeuroAnatomy (LSNA) of the University of Barcelona (Spain). Before and after each dissection, a computed tomography (CT) scan was performed to create a three-dimensional geometric model of the approach performed in the dissection room. The model protocol was designed as follows: (i) a preliminary exploration of each specimen using the preoperative CT scan, (ii) creation of a computer-generated three-dimensional virtual model of the approach, (iii) cadaveric anatomic dissection, and (iv) development of a CT-based model of the approach as a result of the superimposition of predissection and postdissection digital imaging and communications in medicine (DICOM) images of specimens.

RESULTS

This method employing preliminary virtual exploration of each specimen, the creation of a three-dimensional virtual model of the approach, and the overlapping of the predissection and postdissection three-dimensional models was useful to define the exact boundaries of the endoscopic endonasal craniectomy.

CONCLUSIONS

Aside from laboratory anatomic dissection itself, this model is very effective in providing a depiction of bony landmarks and visual feedback of the amount of bone removed, improving the design of the craniectomy in the endoscopic endonasal midline skull base approach.

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.

Endoscopic minimally invasive neurosurgery: emerging techniques and expanding role through an extensive review of the literature and our own experience - part II: extraendoscopic neurosurgery

BACKGROUND/AIMS

The field of minimally invasive neurosurgery has grown dramatically especially in the last decades. This has been possible, in the most part, due to the advancements in technology especially in tools such as the endoscope. The contemporary classification scheme for endoscopic procedures needs to advance as well.

METHODS

The present classification scheme for neuroendoscopic procedures has become confusing because it mainly describes the use of the endoscope as an assisting device to the microscope. The authors propose an update to the current classification that reflects the independence of the endoscope as a tool in minimally invasive neurosurgery.

RESULTS

The proposed classification groups the procedures as 'intraendoscopic' neurosurgery or 'extraendoscopic' neurosurgery (XEN) in relation to the 'axis' of the endoscope. A review of the literature for the XEN group together with exemplary cases is presented.

CONCLUSION

We presented our proposed classification for the endoscope-only surgical procedures. The XEN group is expanded in this article.

The historical evolution of transsphenoidal surgery: facilitation by technological advances

Over the past century, pituitary surgery has undergone multiple evolutions in surgical technique and technological advancements that have resulted in what practitioners now recognize as modern transsphenoidal surgery (TSS). Although the procedure is now well established in current neurosurgical literature, the historical maze that led to its development continues to be of interest because it allows a better appreciation of the unique contributions by the pioneers of the technique, and of the innovative spirit that continues to fuel neurosurgery. The early events in the history of TSS have already been well documented. This paper therefore summarizes the major early transitions along the timeline, and then further concentrates on some of the more recent advancements in TSS, such as the surgical microscope, fluoroscopy, endoscopy, intraoperative imaging, and frameless guidance. The account of each of these innovations is unique because they were each developed as a response to certain historical needs by the surgeon. An understanding of these more recent contributions, coupled with the early history, provides a more complete perspective on modern TSS.

Pituitary tumors: our experience in the prevention of postoperative cerebrospinal fluid leaks after transsphenoidal surgery

The objective was to analyze the management of intraoperative CSF leaks in transsphenoidal surgeries to prevent postoperative cerebrospinal fluid (CSF) leaks. Sixty-three pituitary tumors were operated by transnasal approach. In presence of arachnoidal opening, a fat graft was placed into the sellar cavity, followed by collagen sponge layer and fibrin glue. The sphenoid sinus was also packed with fat graft and collagen sponge. An external CSF lumbar drainage was kept for 2-4 days. The variables analyzed were: intraoperative and postoperative CSF leaks, procedures, and related complications. The overall incidence of postoperative CSF leak was 1.5%. Twenty patients (31.7%) had intraoperative arachnoidal opening, 5% of whom had postoperative CSF leak. There were no reoperations because of CSF leak, and no secondary intrasellar arachnoidoceles. Mean follow-up was 3.6 years. The preventive treatment had good results and there were no complications related to the intervention strategy, encouraging us to continue performing this simple, effective, and inexpensive procedure.

Comparison of endoscopic and microscopic removal of pituitary adenomas: single-surgeon experience and the learning curve

Object

The endoscopic endonasal approach for resection of pituitary lesions is an effective surgical option for tumors of the sella turcica. In this study the authors compared outcomes after either purely endoscopic resection or traditional microscope-aided resection. They also attempted to determine the learning curve associated with a surgical team converting to endoscopic techniques.

Methods

Retrospective data were collected on patients who were surgically treated for a pituitary lesion at the Hospital of the University of Pennsylvania between July 2003 and May 2008. Age, sex, race, presenting symptoms, length of hospital stay, surgical approach, duration of surgery, tumor pathological features, gross-total resection (GTR) of tumor, recurrence of the lesion, and intraoperative and postoperative complications were noted. All procedures were performed by the same senior neurosurgeon, who was initially unfamiliar with the endoscopic endonasal approach.

Results

A total of 25 patients underwent microscopic resection and 25 patients underwent endoscopic resection performed by a single skull base team consisting of the same senior neurosurgeon and otorhinolaryngologist (M.S.G. and B.W.O.). In the microscopically treated cohort, there were 8 intra- or postoperative complications, 6 intraoperative CSF leaks, 17 (77%) of 22 patients had GTR on postoperative imaging, 5 patients underwent ≥ 2 operations, and 10 (59%) of 17 patients reported total symptom resolution at follow-up. The endoscopically treated group had 7 intraor postoperative complications and 7 intraoperative CSF leaks. Of the patients who had pre- and postoperative imaging studies, 14 (66%) of 21 endoscopically treated patients had GTR; 4 patients had ≥ 2 operations, and 10 (66%) of 15 patients reported complete symptom resolution at follow-up. The first 9 patients who were treated endoscopically had a mean surgical time of 3.42 hours and a mean hospital stay of 4.67 days. The next 8 patients treated had a mean surgical time of 3.11 hours and a mean hospital stay of 3.13 days. The final 8 patients treated endoscopically had a mean surgical time of 2.22 hours and a mean hospital stay of 3.88 days. The difference in length of operation between the first 9 and the last 8 patients treated endoscopically was significantly different. There was a trend toward decreased CSF leaks and other complications from the first 2 groups compared with the third group.

Conclusions

In this subset of patients, the use of endoscopic endonasal resection results in a similar complication and symptom resolution rate compared with traditional techniques. The authors postulate that the learning curve for endoscopic resection can be ≤ 17 procedures.

Combined endoscopic and microscopic management of pediatric pituitary region tumors through one nostril: technical note with case illustrations

OBJECTIVE

Sellar and parasellar lesions in the pediatric population have traditionally been approached through either a transsphenoidal hypophysectomy or craniotomy or a combination of the two, with the surgical approach being dictated by the anatomical location and extent of the pathology. The introduction and evolution of the endonasal endoscopic technique has provided a minimally invasive method alone or in combination with the operative microscope for removal of these lesions in the pediatric population. The authors have implemented in their practice the use of endonasal endoscopic-assisted microsurgery in the pediatric population harboring sellar and/or lesions extending to the suprasellar space and report our experience in nine patients.

MATERIALS AND METHODS

Five craniopharyngiomas, one Rathke's cleft cyst, and two pituitary tumors were treated via endonasal endoscopic-assisted microsurgery. Histopathologic examination revealed lymphocytic hypophysitis in one patient with an enhancing lesion in the pituitary stalk. The approach utilized by the authors is performed through one nostril without any resection of the nasal turbinates or nasal septum. The middle turbinate is displaced laterally, while the nasal septum is moved medially.

CONCLUSION

Gross total, near-total, and subtotal resections and a diagnostic biopsy were obtained in six, one, one, and one patients, respectively. The authors were able to safely perform this procedure in nine pediatric patients, and the lack of turbinate or septum resection minimized postoperative discomfort.

Endocrine outcome of endoscopic endonasal transsphenoidal surgery in functioning pituitary adenomas

OBJECTIVE

Microscopic and endoscopic transsphenoidal approach (TSA) are major surgical techniques in the treatment of pituitary adenoma. Endoscopic endonasal transsphenoidal approach (EETSA) has been increasingly used for pituitary adenomas, however, its surgical outcome particularly in functioning pituitary adenoma has been debated. Here, we investigated the endocrine outcome of the patients with growth hormone (GH) and adrenocorticotropic hormone (ACTH) secreting pituitary adenoma treated by EETSA.

METHODS

We treated 80 patients with pituitary adenoma by EETSA since 2004, of which 12 patients were affected by functioning pituitary adenomas (9 GH, 3 ACTH, 0 PRL; 9 macro, 3 micro). Surgical outcome of those patients treated by EETSA was compared with that of the 11 functioning pituitary adenoma patients (8 GH, 3 ACTH; 8 macro, 3 micro) who underwent sublabial microscopic TSA between 1997 and 2003.

RESULTS

Imaging remission based on postoperative MRI was achieved in 8 (73%) and hormonal remission in 5 (45%) of 11 patients treated by sublabial microscopic TSA. Imaging remission was observed in 10 (83%, p=0.640) and hormonal remission in 10 (83%, p=0.081) of 12 patients by EETSA. CSF leakage was noticed in 2 (17%) of EETSA group and in 2 (18%) of sublabial microscopic TSA group. Panhypopituitarism was observed in 1 (9%) of EETSA group and in 3 (27%) of sublabial microscopic TSA group.

CONCLUSION

EETSA appears to be an effective and safe method for the treatment of functioning pituitary adenomas.

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.

Endonasal transsphenoidal pituitary surgery: is tumor volume a key factor in determining outcome?

PURPOSE

This study was conducted to evaluate the role of tumor volume in excision of pituitary adenomas.

MATERIALS AND METHODS

A total of 20 patients with pituitary adenoma underwent surgical excision of the tumor by endonasal transsphenoidal approach.

RESULTS

A preoperative tumor volume of more than 5 mL is associated with a 90.90% probability of residual tumor (P < .05, statistically significant).

CONCLUSION

Tumor volume as a predicting factor for the surgical outcome is an evolving concept. Other factors determining the efficacy of tumor removal are parasellar and suprasellar extension.

Thermal properties of operative endoscopes used in otorhinolaryngology

Objectives:

To measure the thermal properties of operative endoscopes used in otorhinolaryngological practice.

Methods:

A series of endoscopes of varying diameters and angulations were attached to a light source and temperature measurements taken of their shaft and tip; a measurement was also taken 5 mm in front of the endoscope tip.

Results:

Temperature changes took place rapidly. The amount of heat produced by the endoscopes was maximal at the tip, with larger diameter endoscopes attaining a higher temperature. Temperatures on the shaft and in front of the tip reached relatively constant temperatures independent of the type of endoscope. The maximum temperature achieved was 104.6°C for the 4 mm, 0° endoscope. Cooling occurred rapidly after the light source was switched off.

Conclusion:

The heat produced by some endoscopes is sufficiently great to cause thermal injury to tissues. Awareness of the temperatures produced by these endoscopes should prompt clinicians to actively cool their endoscopes during a procedure, before any thermal injury is caused.

Endoscopic endonasal study of the internal carotid artery course and variations

BACKGROUND

With the advance in endoscopic sinus surgery, more procedures are being performed to address challenging lesions and, of particular concern, those around the internal carotid artery (ICA). Despite the current progress in the understanding of endoscopic paranasal sinus anatomy, little information is available about the course and variations of the closely related ICA as seen endoscopically. In this study, we show an endoscopic analysis of the ICA course in a series of advanced endoscopic dissections

METHODS

Ten cadaver heads (20 sides) have been endoscopically dissected. Using an extended approach, a wide sphenoidotomy has been performed as far laterally as the pterygoid base. The latter also has been drilled posteriorly and the ICA was fully exposed from its petrous part up to its termination below the anterior perforated substance of the brain. High-quality endoscopic pictures were produced by coupling the video images with a digital recording system.

RESULTS

The ICA course, landmarks, and segments have been defined and analyzed. The ICA was found to have a variable course that was well appreciated using the multiangled, magnified endoscopic view. The importance of such variation was established in relation to the nearby anatomic structures as well as possible lesions involving this area.

CONCLUSION

The results of this study provide the endoscopic sinus and skull base surgeon with a better understanding of the endoscopic course and variations of the ICA. In experienced hands, such endoscopic orientation should allow safer as well as more effective management of closely related lesions.

Endoscopic endonasal pituitary surgery: surgical and outcome analysis of 50 cases

OBJECTIVE

Microsurgical transsphenoidal surgery for pituitary tumors has been standard therapy for decades and was established by Harvey Cushing in the early twentieth century. Today, endoscopy is increasingly accepted in the therapy of pituitary lesions. In this retrospective study, we analysed the surgical technique and outcome of 50 patients with pituitary lesions treated with an endoscopic endonasal trans-sphenoidal approach.

METHODS

Between January 2004 and July 2005, 50 patients (30 female and 20 male) with pituitary tumors were operated upon using an endoscopic endonasal trans-sphenoidal procedure without nasal speculum or postoperative nasal packing. The follow-up period ranged from 3 to 18 months.

RESULTS

All patients had normal airways through both nostrils immediately after extubation. Postoperative discomfort was minimal and hospitalization was 4-5 days. Three patients developed postoperative transient diabetes insipidus, persisting in one for a further 2 months. Among the 50 patients, total tumor removal was achieved in 47 patients (94%), subtotal in two patients (4%). One patient died intraoperatively due to subarachnoid haemorrhage.

CONCLUSION

The endoscopic endonasal transsphenoidal approach for removing pituitary lesions is a form of minimally invasive surgery offering excellent postoperative results.

History of endoscopic skull base surgery: its evolution and current reality

✓The history of the endoscope exemplifies the manner in which technological advances influence medicine and surgery. Endoscopic systems have evolved and improved, and they currently provide detailed visualization of a variety of deep organ structures. Otorhinolaryngological surgeons have used the endoscope for more than 30 years. In the 1990s, a number of influential neurosurgeons and otorhinolaryngological surgeons began performing purely endoscopic pituitary surgery. Endoscopic transsphenoidal operations are now extending beyond the sella. The collaboration between otorhinolaryngologists and neurosurgeons has produced a new subspecialty of “endoscopic skull base surgery.” There is a great deal of progress still to be made in developing skills, instruments, and improving skull base repair. The extended skull base approaches allow surgical exposures from the olfactory groove to C-2 and to the infratemporal region and jugular fossa laterally. This article discusses the history of the endoscope, the pivotal technological advances, and the key figures in the burgeoning field of endoneurosurgery.

Resection of extensive sellar tumors with extended endoscopic transseptal transsphenoidal approach

The endoscope has recently been used to extensive sellar lesions, but the extended areas of the lesions and operative techniques vary from each study. Here we present our experience with extended endoscopic transseptal transsphenoidal (EETT) approach to 16 patients with extensive sellar lesion and evaluate the feasibility of EETT in different extensive sellar tumor resection. Sixteen patients with extensive sellar lesion were operated by EETT approach in this study. The approach included unilateral posterior septum mucosa resection, posterior septectomy, extended ethmoidectomy and sphenoidoctomy, four tumoral circumferences (bilateral, superior, inferior aspects) isolated and subsequently tumoral removal from outside to inside of the tumors obtained. This surgical procedure is satisfactory for sellar lesion with different juxtasellar extension. After surgery, CT scan and MR image showed that total removal of the tumor was achieved in 10 patients. Six patients who received subtotal resection were treated with postoperative radiation therapy or gamma knife surgery. Two patients developed postoperative cerebrospinal fluid leak that was successfully managed by conservative treatment within 6 days after surgery. No other new postoperative endocrinological or neurological defects occurred. Six months to 5 years follow up indicated that all 16 patients with the visual disturbances and 4 patients with endocrine impairments have recovered or improved. One patient with malignant meningioma died due to recurrence of the tumor 2 years postoperation. Another one patient with malignant inverted papilloma recurred 1 year postoperation and underwent operation and radiation therapy again. The EETT approach might better facilitate the removal of different extensive sellar lesions with maximal preservation of important anatomical structures and nasal function.

Experimental image-guided endoscopic pituitary surgery: a useful learning model

OBJECTIVES

The purpose of this study, which combined image guidance and endocscopic pituitary surgery (EPS), was to test its practicability as a learning tool to acquire the necessary skills in an experimental setting.

METHODS

Ten cadaver-heads were explored using a standard endoscopic transsphenoidal surgical technique combined with the InstaTrak 3500 (GE Medical Systems, Lawrence, MA, USA) image guidance system. The time taken for the experimental setup and the optic-radiologic correlations of topographic landmarks were recorded and photographed.

RESULTS

The average time for setting up the system was 11.9 min+/-2.0, which included head fixation, headset positioning, registration, calibration and verification of the system. With the guidance of the navigation system, the ostium, sellar floor and adjacent structures encountered during EPS could be identified easily and were reflected on the 3D-CT images accurately.

CONCLUSION

The experimental model validated the practicability of image guidance combined with EPS. The non-invasive interactive computer-assisted CT-guided navigational system facilitated the surgical procedure by providing precise spatial relationship between instrument position and adjacent structures. This combination is a useful teaching and learning tool in the cadaver and in patients will be useful, particularly for complex cases and redo-surgery.

Endoscopic endonasal transsphenoidal surgery. Before scrubbing in: tips and tricks

BACKGROUND

The interest in endoscopic endonasal transsphenoidal surgery for the treatment of sellar and perisellar lesions is growing as a consequence of the results achieved in the past 10 years and of the interest by patients, endocrinologists, and neurosurgeons. Furthermore, the special ability of the endoscope to offer a wider and detailed view of anatomic structures is a major advantage that increases the attention of neurosurgeons who seek less invasive procedures and better results. Most neurosurgeons performing transsphenoidal surgery, however, are not used to endoscopy, and changing from microsurgical to endoscopic technique can be difficult and even discouraging, often because of difficulties in the initial phase of the procedure.

TECHNIQUE

With the purpose of helping minimize some of the difficulties, we describe herein useful tips and tricks that mainly concern familiarization with the endoscopic equipment, details of the transsphenoidal anatomy, and endoscopic skills. We stress the steps and details that we judge most important.

CONCLUSION

We believe that by following these recommendations neurosurgeons can overcome, or even avoid, the difficulties frequently encountered transsphenoidal surgery, allowing them to safely and efficiently perform endonasal transsphenoidal endoscopic procedures.

Endoscopic, endonasal extended transsphenoidal, transplanum transtuberculum approach for resection of suprasellar lesions

OBJECT

The extended transsphenoidal approach is a less invasive method for removing purely suprasellar lesions compared with traditional transcranial approaches. Most advocates have used a sublabial incision and a microscope and have reported a significant risk of cerebrospinal fluid (CSF) leakage. The authors report on a series of purely endoscopic endonasal surgeries for resection of suprasellar supradiaphragmatic lesions above a normal-sized sella turcica with a low risk of CSF leakage.

METHODS

A purely endoscopic endonasal approach was used to remove suprasellar lesions in a series of 10 patients. Five lesions were prechiasmal (three tuberculum sellae and two planum sphenoidale meningiomas) and five were post-chiasmal (four craniopharyngiomas and one Rathke cleft cyst). The floor of the planum sphenoidale and the sella turcica was reconstructed using a multilayer closure with autologous and synthetic materials. Spinal drainage was performed in only five cases. Complete resection of the lesions was achieved in all but one patient. The pituitary stalk was preserved in all but one patient, whose stalk was invaded by a craniopharyngioma and who had preoperative diabetes insipidus (DI). Vision improved postoperatively in all patients with preoperative impairment. Six patients had temporary DI; in five, the DI became permanent. Four patients with craniopharyngiomas required cortisone and thyroid replacement. After a mean follow up of 10 months, there was only one transient CSF leak when a lumbar drain was clamped prematurely on postoperative Day 5.

CONCLUSIONS

A purely endoscopic endonasal approach to suprasellar supradiaphragmatic lesions is a feasible minimally invasive alternative to craniotomy. With a multilayer closure, the risk of CSF leakage is low and lumbar drainage can be avoided. A larger series will be required to validate this approach.

Endoscopic pituitary surgery with and without image guidance: an experimental comparison

BACKGROUND

The combination of image guidance and endoscopy is the newest trend in pituitary surgery. To assess the impact of image guidance on EPS, we measured and calculated the accuracy of the system and compared some critical surgical steps with and without image guidance under experimental conditions in terms of surgical time and precision.

METHODS

Twenty cadaver heads were explored by standard endoscopic transsphenoidal surgical technique. Optic-radiologic correlations of topographic landmarks were photographed, and the system accuracy and actual visual accuracy were recorded. Some important anatomical parameters were measured in surgical field and on navigation system, and the differences were calculated and analyzed. Some critical surgical steps were recorded and compared between with and without image guidance.

RESULTS

The system accuracy (root mean square), calculated by the computer automatically, showed a mean value of 0.28 +/- 0.06 mm. In some cases, there was a small discrepancy between the visible position of the pointer and its counterpart on the navigation system; we coined this actual visual accuracy. The average value was 1.53 +/- 0.49 mm. The maximum difference between the measurements from the navigation system and from their actual visual counterparts was less than 7%. With and without image guidance, in normal anatomical conditioning, there was no statistically significant difference between the duration of ostium sphenoidale exposure and sellar window creation; however, in anatomical variations, the surgical time was shown to be significantly shorter when navigation was used.

CONCLUSION

We have demonstrated in this experimental setting that the electromagnetic tracking image guidance possesses a high accuracy at millimetric level and therefore provides precise localization and orientation in EPS. With the assistance of neuronavigation system, it is advantageous not only in saving operating time, but also, more importantly, in enhancing the orientation, thus, rendering surgeries safer and more efficient. During the in vivo pituitary surgery, EPS with image guidance can provide accurate and reliable stereoinformation to achieve better results with lesser risks, particularly in complex cases or in reoperations, even in the hands of experienced surgeons.