Re-evaluation of the role of image guidance in minimally invasive pituitary surgery: benefits and outcomes

Skull-Base Surgery-A Narrative Review on Current Approaches and Future Developments in Surgical Navigation

Surgical navigation technology combines patient imaging studies with intraoperative real-time data to improve surgical precision and patient outcomes. The navigation workflow can also include preoperative planning, which can reliably simulate the intended resection and reconstruction. The advantage of this approach in skull-base surgery is that it guides access into a complex three-dimensional area and orients tumors intraoperatively with regard to critical structures, such as the orbit, carotid artery and brain. This enhances a surgeon's capabilities to preserve normal anatomy while resecting tumors with adequate margins. The aim of this narrative review is to outline the state of the art and the future directions of surgical navigation in the skull base, focusing on the advantages and pitfalls of this technique. We will also present our group experience in this field, within the frame of the current research trends.

Image-Guided Surgery and Intraoperative Imaging in Rhinology: Clinical Update and Current State of the Art

INTRODUCTION

Image-guided surgery (IGS) has gained widespread acceptance in otorhinolaryngology for its applications in sinus and skull base surgery. Although the core concepts of IGS have not changed, advances in image guidance technology, including the incorporation of intraoperative imaging, have the potential to enhance surgical education, allow for more rigorous preoperative planning, and aid in more complete surgery with improved outcomes.

OBJECTIVES

Provide a clinical update regarding the use of image guidance and intraoperative imaging in the field of rhinology and endoscopic skull base surgery with a focus on current state of the art technologies.

METHODS

English-language studies published in PubMed, Cochrane, and Embase were searched for articles relating to image-guided sinus surgery, skull base surgery, and intraoperative imaging. Relevant studies were reviewed and critical appraisals were included in this clinical update, highlighting current state of the art advances.

CONCLUSIONS

As image guidance and intraoperative imaging systems have advanced, their applications in sinus and skull base surgery have expanded. Both technologies offer invaluable real-time feedback on the status and progress of surgery, and thus may help to improve the completeness of surgery and overall outcomes. Recent advances such as augmented and virtual reality offer a window into the future of IGS. Future advancements should aim to enhance the surgeon's operative experience by improving user satisfaction and ultimately lead to better surgical results.

ICAR: endoscopic skull-base surgery

BACKGROUND

Endoscopic skull-base surgery (ESBS) is employed in the management of diverse skull-base pathologies. Paralleling the increased utilization of ESBS, the literature in this field has expanded rapidly. However, the rarity of these diseases, the inherent challenges of surgical studies, and the continued learning curve in ESBS have resulted in significant variability in the quality of the literature. To consolidate and critically appraise the available literature, experts in skull-base surgery have produced the International Consensus Statement on Endoscopic Skull-Base Surgery (ICAR:ESBS).

METHODS

Using previously described methodology, topics spanning the breadth of ESBS were identified and assigned a literature review, evidence-based review or evidence-based review with recommendations format. Subsequently, each topic was written and then reviewed by skull-base surgeons in both neurosurgery and otolaryngology. Following this iterative review process, the ICAR:ESBS document was synthesized and reviewed by all authors for consensus.

RESULTS

The ICAR:ESBS document addresses the role of ESBS in primary cerebrospinal fluid (CSF) rhinorrhea, intradural tumors, benign skull-base and orbital pathology, sinonasal malignancies, and clival lesions. Additionally, specific challenges in ESBS including endoscopic reconstruction and complication management were evaluated.

CONCLUSION

A critical review of the literature in ESBS demonstrates at least the equivalency of ESBS with alternative approaches in pathologies such as CSF rhinorrhea and pituitary adenoma as well as improved reconstructive techniques in reducing CSF leaks. Evidence-based recommendations are limited in other pathologies and these significant knowledge gaps call upon the skull-base community to embrace these opportunities and collaboratively address these shortcomings.

Improved Surgical Safety via Intraoperative Navigation for Transnasal Transsphenoidal Resection of Pituitary Adenomas

Objectives  Intraoperative navigation during neurosurgery can aid in the detection of critical structures and target lesions. The safety and efficacy of intraoperative, stereotactic computed tomography (CT) in the transnasal transsphenoidal resection of pituitary adenomas were explored. Design  Retrospective chart review Setting  Tertiary care hospital Participants  Patients who underwent transsphenoidal resection of pituitary adenomas from February 2002 to May 2017. Intraoperative stereotactic CT navigation was used for all patients after mid-October 2013. Main Outcome Measures  Operative time, estimated blood loss, gross total resection rate. Results  Of 634 patients included, 175 underwent surgery with intraoperative navigation and 444 had no intraoperative navigation during surgery. There was no difference in mean age, sex, tumor type, or tumor size between the two groups. Operative time, endoscope use, cerebrospinal fluid diversion, and estimated blood loss were also similar. Two patients showed intraoperative, iatrogenic misdirection in the absence of stereotactic CT navigation ( p  = 0.99) but similar numbers of patients having navigated and non-navigated surgery returned to the operating room, underwent gross total resection, and showed endocrinological normalization. Conclusions  These results suggest that intraoperative navigation can reduce injury without resulting in increased operative time, estimated blood loss, or reduction in gross total resection.

Nationwide analysis of unplanned 30-day readmissions after transsphenoidal pituitary surgery

BACKGROUND

Transsphenoidal pituitary surgery has evolved into a safe procedure with shorter hospitalizations, yet unplanned readmissions remain a quality measure for which there is a paucity of data. We sought to examine rates, timing, etiologic factors, and costs surrounding readmission after transsphenoidal pituitary surgery.

METHODS

The Nationwide Readmissions Database (NRD) was queried for patients who underwent transsphenoidal pituitary between January 2013 and November 2013. Patient, procedure, admission, and hospital-level characteristics were compared for patients with and without unplanned 30-day readmission. Multivariate logistic regression was used to identify readmission predictors. A total of 8546 patients were included in this retrospective study.

RESULTS

A total of 8546 patients with a median age of 54 years and female predominance were identified, with 742 patients experiencing at least 1 unplanned readmission within 30 days of index admission. Hypertension, hypothyroidism, diabetes, and obesity were common comorbidities among readmitted patients. Readmission was most frequently because of nervous system complications, followed by neurohypophyseal or electrolyte disorders, cerebrospinal fluid leak, hemorrhage, and meningitis. Median length and cost of stay of index admission was greater in the readmission group (p < 0.001). Fluid and electrolyte disorders as well as neurologic disease (most commonly epilepsy or convulsions) present on initial admission were predictive of length of initial stay and readmission (p < 0.001). Median readmission cost was $7723 and was expected to occur within 7 days.

CONCLUSION

Approximately 8.7% of patients undergoing transsphenoidal pituitary surgery experience an unplanned readmission within 30 days of discharge. Risk factors identified should be considered to reduce preventable readmissions and identify medically complex patients.

Transsphenoidal surgery: accuracy of an image-guided neuronavigation system to approach the pituitary fossa (sella turcica)

OBJECTIVE

To determine the accuracy of locating the pituitary fossa with the Brainsight neuronavigation system by determining the mean target error of the rostral (tuberculum sellae) and caudal (dorsum sellae) margins of the pituitary fossa.

STUDY DESIGN

Experimental cadaveric study.

ANIMALS

Ten canine cadavers.

METHODS

Computed tomography (CT) and MRI were performed on each cadaver with fiducials in place. Images were saved to the neuronavigation computer and used to plan the drilling approach. The cadavers were placed in the surgical head clamp of the Brainsight system and positioned for a transsphenoidal approach. On the basis of the planning, 2 localization points were drilled, 1 each at the rostral and caudal margins of the pituitary fossa, and CT was repeated. Error was assessed from the difference in millimeters between the targets identified during Brainsight planning and the actual location of the 2 points drilled on each cadaver skull as identified by postdrilling CT.

RESULTS

The rostral and caudal margins of the pituitary fossa provided 2 target points per cadaver. The median target error (interquartile range) for all target sites (n = 20) was 3.533 mm (range, 2.013-4.745).

CONCLUSION

This stereotactic system allowed the surgeon to locate the rostral and caudal margins of the pituitary fossa with clinically acceptable accuracy and confidence.

CLINICAL SIGNIFICANCE

Using the Brainsight neuronavigation system for localization during transsphenoidal hypophysectomy may decrease morbidity and surgical time.

A Telerobotic System for Transnasal Surgery

Mechanics-based models of concentric tube continuum robots have recently achieved a level of sophistication that makes it possible to begin to apply these robots to a variety of real-world clinical scenarios. Endonasal skull base surgery is one such application, where their small diameter and tentacle like dexterity are particularly advantageous. In this paper we provide the medical motivation for an endonasal surgical robot featuring concentric tube manipulators, and describe our model-based design and teleoperation methods, as well as a complete system incorporating image-guidance. Experimental demonstrations using a laparoscopic training task, a cadaver reachability study, and a phantom tumor resection experiment illustrate that both novice and expert users can effectively teleoperate the system, and that skull base surgeons can use the robot to achieve their objectives in a realistic surgical scenario.