Paul T. Russell

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.

A bimanual teleoperated system for endonasal skull base surgery

We describe transnasal skull base surgery, including the current clinical procedure and the ways in which a robotic system has the potential to enhance the current standard of care. The available workspace is characterized by segmenting medical images and reconstructing the available 3D geometry. We then describe thin, “tentacle-like” robotic tools with shafts constructed from concentric tube robots, and an actuation unit designed to robotically control them in a teleoperated setting. Lastly, we discuss the results of a proof-of-concept study in a cadaveric specimen, illustrating the ability of the robot to access clinically relevant skull base targets.

Robotic surgery for the sinuses and skull base: what are the possibilities and what are the obstacles?

Purpose of reviewRobotic surgery in otolaryngology – head and neck surgery has become a valuable tool in certain anatomic approaches; however, its application in surgery of the paranasal sinuses and anterior skull base is still in an investigatory phase and requires further evaluation. Recent findingsExisting robotic surgical systems face particular limitations in their application at the skull base because of instrument size and lack of variability. Unfortunately, only one system is available commercially that is applicable in the head and neck region and FDA approved for use in patients. This system, although advantageous in many otolaryngologic procedures, is difficult to use for endoscopic sinus and skull base surgery. However, other systems that target this anatomic subsite specifically are in development and show promise. Advances in the design of robotic arms, materials, and shape will potentially give surgeons a significant advantage over traditional endoscopic techniques. SummaryThis article will review the current applications of robotic systems in paranasal sinus and skull base surgery, describe the requirements of a robotic system for use in this type of surgery, and describe a system under development at our institution.

Revisiting the interpretation of positive sinus CT findings: a radiological and symptom-based review.

Objective: It is widely believed that a high percentage of normal, healthy patients without sinusitis symptoms have abnormal findings on sinus CT. Experiences of the authors of this study suggest otherwise. Study Design: Cross-sectional survey. Subjects and Methods: Head/sinus CT scans of 50 consecutive patients from each of three study groups were reviewed. Group 1 consisted of patients without any sinus symptoms. Group 2 consisted of patients with acute headache symptoms. Group 3 consisted of patients with complaints consistent with chronic sinusitis. CT scans were evaluated with the Lund-Mackay scoring system. Results: In the asymptomatic patient group (group 1), six (3%) patients had positive sinus CT scan findings, compared with 11 (5.5%) in the acutely symptomatic group (group 2), and 32 (64%) in the chronically symptomatic group (group 3). In the chronically symptomatic group (group 3), 64 percent of patients were allergic compared with 18% of the acute headache group (group 2) and 8 percent of the asymptomatic patient group (group 1). Conclusion: Results of this study suggest that symptomatic sinus patients are much more likely to have positive sinus CT scan findings than asymptomatic patients. Conversely, normal healthy patients should not be expected to have abnormal sinus CT scans.

Balloon sinuplasty for the surgical management of immunocompromised and critically ill patients with acute rhinosinusitis.

Objective: The purpose of this study was to review use of balloon sinuplasty for surgical treatment in critically ill patients with acute sinusitis. Study Design: Case series with chart review. Subjects and Methods: Patients who underwent balloon sinuplasty between October 2007 and March 2008 were identified. Medical records of the subset of patients who were immunocompromised or otherwise critically ill were analyzed. Results: Thirty-one patients underwent balloon sinuplasty at our institution between October 2007 and March 2008. We identified five critically ill patients with sinus disease within this group. Patient ages ranged from 15 to 51 years with no sex preponderance. All patients had focal findings on a sinus CT scan. In all cases, purulent drainage was noted intraoperatively. All patients returned to baseline health meeting discharge criteria after treatment. Conclusion: Balloon sinuplasty represents a potentially less invasive surgical option than standard Functional Endoscopic Sinus Surgery (FESS) and should be considered in the treatment of critically ill or immunocompromised patients.

Endoscopic endonasal repair of difficult-to-access cerebrospinal fluid leaks of the frontal sinus

Background Cerebrospinal fluid (CSF) leaks located within the frontal sinus can be difficult to repair effectively. Additional challenges arise from the need to simultaneously repair the leak or defect and to ensure the future patency of the sinus itself. Methods The cases of two patients who underwent surgical repair of CSF leaks and skull base defects located in difficult to access locations within their frontal sinuses were reviewed. Results Two patients with CSF leaks in the frontal sinus underwent surgery to repair the leaks. The leaks were in the superomedial and superolateral locations within the sinus. One leak (in the superolateral location) was secondary to iatrogenic surgical trauma during craniotomy. The second leak (in the superomedial location) was secondary to congenital encephalocele. Surgical approach to ensure adequate exposure was via endoscopic modified Lothrop procedure. Successful repair was undertaken via underlay technique. At follow-up (27 and 7 months, respectively), frontal sinuses remained patent without evidence of CSF leak. Conclusion CSF leaks located in medial and lateral areas of the frontal sinus may be successfully repaired via endonasal approach with endoscopic modified Lothrop. Repair in this manner requires that attention be paid both to achieving a complete repair and to maintaining a patent sinus drainage pathway.

REMODEL larger cohort with long-term outcomes and meta-analysis of standalone balloon dilation studies.

To provide the final results from the REMODEL (randomized evaluation of maxillary antrostomy versus ostial dilation efficacy through long‐term follow‐up) full‐study cohorts and perform meta‐analyses of standalone balloon sinus dilation studies to explore long‐term outcomes in a large patient sample.

Current issues in the management of sinonasal methicillin-resistant Staphylococcus aureus.

Purpose of reviewStaphylococcus aureus is an important pathogen, contributing to both pediatric and adult infections in the USA. In recent years, methicillin-resistant Staphylococcus aureus (MRSA) has become a source of public fear and outcry. In this article, we review facts and fiction of sinonasal MRSA. Recent findingsAlthough the exact role of bacteria in chronic rhinosinusitis continues to be debated, the role of MRSA in these patients is even less apparent. When MRSA is involved, there are few to guide treatment. Oral, parenteral, and topical antibiotics are all used in the treatment of sinonasal MRSA. MRSA eradication has been advocated by some; however, there are few data to support the efficacy of eradication. Current treatment regimens by the authors are reviewed. SummaryThere is much that is not known about the role of MRSA in sinonasal infection, and the impact of sinonasal MRSA on the health quality of the community also remains undefined. Treatment outlines are presented; however, with the current state of data, these treatment preferences lack a solid, evidence-based foundation that is favored. Future studies will lay the foundation for more rigorously supported treatment algorithms.

An experimental feasibility study on robotic endonasal telesurgery.

BACKGROUND Novel robots have recently been developed specifically for endonasal surgery. They can deliver several thin, tentacle-like surgical instruments through a single nostril. Among the many potential advantages of such a robotic system is the prospect of telesurgery over long distances. OBJECTIVE To describe a phantom pituitary tumor removal done by a surgeon in Nashville, Tennessee, controlling a robot located approximately 800 km away in Chapel Hill, North Carolina, the first remote telesurgery experiment involving tentacle-like concentric tube manipulators. METHODS A phantom pituitary tumor removal experiment was conducted twice, once locally and once remotely, with the robotic system. Robot commands and video were transmitted across the Internet. The latency of the system was evaluated quantitatively in both local and remote cases to determine the effect of the 800-km distance between the surgeon and robot. RESULTS We measured a control and video latency of < 100 milliseconds in the remote case. Qualitatively, the surgeon was able to carry out the experiment easily and observed no discernable difference between the remote and local cases. CONCLUSION Telesurgery over long distances is feasible with this robotic system. In the longer term, this may enable expert skull base surgeons to help many more patients by performing surgeries remotely over long distances.

Endonasal Skull Base Tumor Removal Using Concentric Tube Continuum Robots: A Phantom Study

Objectives The purpose of this study is to experimentally evaluate the use of concentric tube continuum robots in endonasal skull base tumor removal. This new type of surgical robot offers many advantages over existing straight and rigid surgical tools including added dexterity, the ability to scale movements, and the ability to rotate the end effector while leaving the robot fixed in space. In this study, a concentric tube continuum robot was used to remove simulated pituitary tumors from a skull phantom. Design The robot was teleoperated by experienced skull base surgeons to remove a phantom pituitary tumor within a skull. Percentage resection was measured by weight. Resection duration was timed. Setting Academic research laboratory. Main Outcome Measures Percentage removal of tumor material and procedure duration. Results Average removal percentage of 79.8 ± 5.9% and average time to complete procedure of 12.5 ± 4.1 minutes (n = 20). Conclusions The robotic system presented here for use in endonasal skull base surgery shows promise in improving the dexterity, tool motion, and end effector capabilities currently available with straight and rigid tools while remaining an effective tool for resecting the tumor.