Robot-assisted transoral odontoidectomy : experiment in new minimally invasive technology, a cadaveric study

Transoral Robotic-Assisted Neurosurgery for Skull Base and Upper Spine Lesions

OBJECTIVE

The application of the da Vinci Surgical System in neurosurgery is limited due to technical difficulties requiring precise maneuvers and small instruments. This study details the advantages and disadvantages of robotics in neurosurgery and the reachable range of the transoral approach to lesions of the skull base and upper cervical spine.

METHODS

In a cadaver study, the da Vinci Xi robot, lacking haptic feedback, was utilized for sagittal and coronal approaches on 5 heads, facilitating dura suturing in 3, with a 30°-angled drill for bone removal.

RESULTS

Perfect exposure of all the nasopharyngeal sites, clivus, sellar, and choana, including the bilateral eustachian tubes, was achieved without any external incisions using this palatal split approach of transoral robotic surgery. The time required to perform a single stitch, knot, and complete single suture in robotic suturing of deep-seated were significantly less compared to manual suturing via the endonasal approach.

CONCLUSION

This is the first report to show the feasibility of suturing the dural defect in deep-seated lesions transorally and revealed that the limit of reach in the coronal plane via a transoral approach with incision of the soft palate is the foramen ovale. This preclinical investigation also showed that the transoral robotic approach is feasible for lesions extending from the sellar to the C2 in the sagittal plane. Refinement of robotic instruments for specific anatomic sites and future neurosurgical studies are needed to further demonstrate the feasibility and effectiveness of this system in treating benign and malignant skull base lesions.

Full-Endoscopic Transcervical Ventral Decompression for Pathologies of Craniovertebral Junction: Case Series

Odontoidectomy is very effective for the decompression of the ventral craniovertebral junction (CVJ). Various approaches are available for the direct ventral decompression of the CVJ. Because there are many disadvantages of open transoral approach, endoscopic odontoidectomy was developed. There are 3 approaches in endoscopic odontoidectomy. We report transcervical retropharyngeal endoscopic approach for the ventral CVJ in this paper. Three patients with different pathologies received operations using this approach. The decompression was enough and surgical invasion was less in all patients. Each endoscopic approach has some advantages and different working regions due to their approach trajectories, but transcervical retropharyngeal approach is very familiar for our neurospinal surgeons and has a relatively large working area. This approach might have the chance to take the place of open transoral approach for endoscopic spinal surgeons.

Robotic spine surgery: Ushering in a new era

The endeavour to make spine surgery safe with reproducible, consistent outcomes has led to growing interest and research in the field of intraoperative imaging, navigation and robotics. The advent of surgical robot systems in spine surgery is relatively recent - with only a few systems approved for commercial use. At present, pedicle screw insertion remains the primary application of robotic systems in spine surgery. The purported advantages of robot-assisted pedicle screw insertion over other conventional techniques are its increased accuracy, reproducible consistency and reduced radiation exposure. Many of these claims have been supported or refuted by individual studies - and high quality evidence for the same is lacking. Robotic spine surgery also has its share of limitations which include increased operative time, considerable learning curve and technical pitfalls unique to the robotic systems. The applications of robotic spine surgery are evolving and expanding to spinal deformity, spine oncology and needle-based interventional treatments. This review provides an overview of the evolution and current status of robotic spine surgery along with an evidence-based discussion of its current applications in spine surgery.

Pure Robotic Surgery for Odontoid Tumor: First Case

BACKGROUND

Transoral robotic surgery has been used successfully to assist many surgical procedures. Here, we report its first use as pure robotic surgery, applied to excise an odontoid metastatic mass.

CASE DESCRIPTION

A 48-year-old woman was hospitalized due to a lesion consistent with metastasis that extended to the pharyngeal constrictor muscles and that had completely destroyed the odontoid bone. Occipitocervical fixation was performed initially, and transoral surgery took place 5 days later. The da Vinci Surgical System Robot was used to resect the tumor. The patient was discharged with a very good general condition.

CONCLUSIONS

This article presents the first pure robotic surgery for odontoid. The increasing number of robot-assisted cases will demonstrate the necessity of this evolution in neurosurgery and should accelerate the process.

Transoral robotic surgery for sellar tumors: first clinical study

OBJECTIVE

The aim of this study was to confirm the feasibility of an innovative transoral robotic surgery (TORS), using the da Vinci Surgical System, for patients with sellar tumors. This technique was designed to offer a new minimally invasive approach, without soft-palate splitting, that avoids the rhinological side effects of classic endonasal approaches.

METHODS

The authors performed a prospective study of TORS in patients with symptomatic sellar tumors. Specific anatomical features were required for inclusion in the study and were determined on the basis of preoperative open-mouth CT scans of the brain. The main outcome measure was sellar accessibility using the robot. Resection quality, mean operative time, postoperative changes in patients' vision, side effects, and complications were additionally reported.

RESULTS

Between February and May 2016, 4 patients (all female, mean age 49.5 years) underwent TORS for resection of sellar tumors as participants in this study. All patients presented with symptomatic visual deficits confirmed as bitemporal hemianopsia. All tumors had a suprasellar portion and a cystic part. In all 4 cases, the operation was performed via TORS, without the need for a second surgery. Sella turcica accessibility was satisfactory in all cases. In 3 cases, tumor resection was complete. The mean operative time was 2 hours 43 minutes. Three patients had a significant visual improvement at Day 1. No rhinological side effects or complications in patients occurred. No pathological examination was performed regarding the fluid component of the tumors. There was 1 postoperative delayed CSF leak and 1 case of transient diabetes insipidus. Side effects specific to TORS included minor sore throat, transient hypernasal speech, and 1 case of delayed otitis media. The mean length of hospital stay and mean follow up were 8.25 days and 82 days, respectively.

CONCLUSIONS

To our knowledge, this is the first report of the surgical treatment of sellar tumors by means of a minimally invasive TORS. This approach using the da Vinci Surgical System seems feasible and constitutes an innovative neurosurgical technique that may avoid the adverse side effects and technical disadvantages of the classic transsphenoidal route. Moreover, TORS allows an inferosuperior approach to the sella turcica, which is a key point, as the tumor is approached in the direction of its growth.

Transoral robotic-assisted surgery for the approach to anterior cervical spine lesions

The Da Vinci robotic surgical system is increasingly being used by head and neck surgeons in transoral approaches for head and neck cancer. Our experience using the Da Vinci system for transoral robotic-assisted surgery (TORS) is presented. The feasibility of TORS for lesions involving the anterior portion of C1-C2 and the cranio-cervical junction has been evaluated from an anatomical viewpoint in a cadaveric laboratory. Two patients treated using the Da Vinci system to reach C1-C2 benign lesions are presented. The anatomical cadaveric study showed that this approach is safe and feasible. The first two cases which we describe confirmed the advantages of the Da Vinci system in the anterior approach to the cervical spine and allowed the limitations of this procedure to be assessed. TORS may be useful to reach anterior lesions of the cervical spine localized at the level of C1 and C2: first, for removal of small benign and well-delineated lesions; and second, for diagnostic purposes with biopsy of large lesions. Further studies and new instruments are needed to confirm the safety and results of this approach in terms of morbidity.

Endoscopic approach to the upper cervical spine and clivus: an anatomical study of the upper limits of the transoral corridor

BACKGROUND

Recent advances in endoscopic techniques have allowed minimally invasive approaches to the cranio-vertebral junction (CVJ) through the oropharynx (ETA) in addition to the transnasal approach (EEA). These minimally invasive endoscopic techniques allow for increased surgical exposure using no visible incisions, with a potential less morbidity. The ability to know preoperatively the limit of the ETA is vital for the surgical planning in order to better address CVJ pathology. The aim of the present study is to determine the anatomical limits of endoscopic dissection of the skull base and upper cervical spine through the transoral corridor and the superior limit reached by adopting this approach.

METHODS

Six fresh-frozen adult cadaver heads were dissected adopting ETA preserving the hard and soft palate. The most superior extent of the exposure was dissected. Post-operative CT scans were performed to confirm the superior extent.

RESULTS

The superior most limit of dissection corresponded to the sphenoid-occipital junction, where the basilar portion of the occipital bone joins with the sphenoid bone's body. This ranged from 12.7 to 18.9 mm above the line of the hard palate. This was achieved without having to transgress any of the palatine structures.

CONCLUSIONS

The sphenoid-occipital junction represents the rostral limit of endoscopic transoral approach to the lower skull base and CVJ area. This approach is limited superiorly by the orientation of the hard palate and mouth aperture and lower dentition due to the linear nature of the endoscope. Using the endoscope for this approach can allow for a more superior exposure than the traditional open transoral approach.

Evolution from microscopic transoral to endoscopic endonasal odontoidectomy

OBJECT

The goal of this study was to compare the indications, benefits, and complications between the endoscopic endonasal approach (EEA) and the microscopic transoral approach to perform an odontoidectomy. Transoral approaches have been standard for odontoidectomy procedures; however, the potential benefits of the EEA might be demonstrated to be a more innocuous technique. The authors present their experience with 12 consecutive cases that required odontoidectomy and posterior instrumentation.

METHODS

Twelve consecutive cases of craniovertebral junction instability with or without basilar invagination were diagnosed at the National Institute of Neurology and Neurosurgery in Mexico City, Mexico, between January 2009 and January 2013. The EEA was used for 5 cases in which the odontoid process was above the nasopalatine line, and was compared with 7 cases in which the odontoid process was beneath the nasopalatine line; these were treated using the transoral microscopic approach (TMA). Odontoidectomy was performed after occipital-cervical or cervical posterior augmentation with lateral mass and translaminar screws. One case was previously fused (Oc-C4 fusion). The senior author performed all surgeries. American Spinal Injury Association scores were documented before surgical treatment and after at least 6 months of follow-up.

RESULTS

Neurological improvement after odontoidectomy was similar for both groups. From the transoral group, 2 patients had postoperative dysphonia, 1 patient presented with dysphagia, and 1 patient had intraoperative CSF leakage. The endoscopic procedure required longer surgical time, less time to extubation and oral feeding, a shorter hospital stay, and no complications in this series.

CONCLUSIONS

Endoscopic endonasal odontoidectomy is a feasible, safe, and well-tolerated procedure. In this small series there was no difference in the outcome between the EEA and the TMA; however, fewer complications were documented with the endonasal technique.

da Vinci robot-assisted keyhole neurosurgery: a cadaver study on feasibility and safety

The goal of this cadaver study was to evaluate the feasibility and safety of da Vinci robot-assisted keyhole neurosurgery. Several keyhole craniotomies were fashioned including supraorbital subfrontal, retrosigmoid and supracerebellar infratentorial. In each case, a simple durotomy was performed, and the flap was retracted. The da Vinci surgical system was then used to perform arachnoid dissection towards the deep-seated intracranial cisterns. It was not possible to simultaneously pass the 12-mm endoscope and instruments through the keyhole craniotomy in any of the approaches performed, limiting visualization. The articulated instruments provided greater dexterity than existing tools, but the instrument arms could not be placed in parallel through the keyhole craniotomy and, therefore, could not be advanced to the deep cisterns without significant clashing. The da Vinci console offered considerable ergonomic advantages over the existing operating room arrangement, allowing the operating surgeon to remain non-sterile and seated comfortably throughout the procedure. However, the lack of haptic feedback was a notable limitation. In conclusion, while robotic platforms have the potential to greatly enhance the performance of transcranial approaches, there is strong justification for research into next-generation robots, better suited to keyhole neurosurgery.

Robotics in keyhole transcranial endoscope-assisted microsurgery: a critical review of existing systems and proposed specifications for new robotic platforms

BACKGROUND

Over the past decade, advances in image guidance, endoscopy, and tube-shaft instruments have allowed for the further development of keyhole transcranial endoscope-assisted microsurgery, utilizing smaller craniotomies and minimizing exposure and manipulation of unaffected brain tissue. Although such approaches offer the possibility of shorter operating times, reduced morbidity and mortality, and improved long-term outcomes, the technical skills required to perform such surgery are inevitably greater than for traditional open surgical techniques, and they have not been widely adopted by neurosurgeons. Surgical robotics, which has the ability to improve visualization and increase dexterity, therefore has the potential to enhance surgical performance.

OBJECTIVE

To evaluate the role of surgical robots in keyhole transcranial endoscope-assisted microsurgery.

METHODS

The technical challenges faced by surgeons utilizing keyhole craniotomies were reviewed, and a thorough appraisal of presently available robotic systems was performed.

RESULTS

Surgical robotic systems have the potential to incorporate advances in augmented reality, stereoendoscopy, and jointed-wrist instruments, and therefore to significantly impact the field of keyhole neurosurgery. To date, over 30 robotic systems have been applied to neurosurgical procedures. The vast majority of these robots are best described as supervisory controlled, and are designed for stereotactic or image-guided surgery. Few telesurgical robots are suitable for keyhole neurosurgical approaches, and none are in widespread clinical use in the field.

CONCLUSION

New robotic platforms in minimally invasive neurosurgery must possess clear and unambiguous advantages over conventional approaches if they are to achieve significant clinical penetration.

Transoral robotic-assisted skull base surgery to approach the sella turcica: cadaveric study

Transoral robotic surgery (TORS) offers new possibilities that have not been experimented in the field of minimally invasive skull base neurosurgery. We propose to evaluate the feasibility of transoral approach to the sella turcica with the da Vinci system on cadavers. We performed four robot-assisted dissections on human fresh cadavers in order to reach the pituitary fossa by the oral cavity. Cavum mucosa dissection was performed by the head and neck surgeon at the console and then the sphenoid was drilled by the neurosurgeon at the bedside, with intraoperative fluoroscopy and a "double surgeon" control. Mucosa closure was attempted with robotic arms. We succeeded in performing a sellar opening in all cadavers with a minimally invasive approach, as the hard palate was never drilled. The video endoscope offered a large view inside the sphenoidal sinus, as observed in transnasal endoscopy, but with 3D visualization. The camera arm could be inserted into the sphenoidal sinus, and instrument arms in the pituitary fossa. Operative time to reach the pituitary fossa was approximately 60 min in all procedures: 20 min of initial setup, 10 min of mucosal dissection, and 30 min of sphenoid surgery. New anatomical landmarks were defined. Advantages and pitfalls of such an unpublished technique were discussed. This is the first cadaveric study reported da Vinci robotic transoral approach to the sella turcica with a minimally invasive procedure. This innovative technique may modify the usual pituitary adenoma removal as the sella is approached infero-superiorly.

Navigation, robotics, and intraoperative imaging in spinal surgery

Spinal navigation is a technique gaining increasing popularity. Different approaches as CT-based or intraoperative imaging-based navigation are available, requiring different methods of patient registration, bearing certain advantages and disadvantages. So far, a large number of studies assessed the accuracy of pedicle screw implantation in the cervical, thoracic, and lumbar spine, elucidating the advantages of image guidance. However, a clear proof of patient benefit is missing, so far. Spinal navigation is closely related to intraoperative 3D imaging providing an imaging dataset for navigational use and the opportunity for immediate intraoperative assessment of final screw position giving the option of immediate screw revision if necessary. Thus, postoperative imaging and a potential revision surgery for screw correction become dispensable.Different concept of spinal robotics as the DaVinci system and SpineAssist are under investigation.

The naso-axial line: a new method of accurately predicting the inferior limit of the endoscopic endonasal approach to the craniovertebral junction

BACKGROUND

The endoscopic endonasal approach (EEA) has developed as an emerging surgical corridor to the craniovertebral junction (CVJ). In addition to understanding its indications and surgical anatomy, the ability to predict its inferior limit is vital for optimal surgical planning.

OBJECTIVE

To develop a method that accurately predicts the inferior limit of the EEA on the CVJ radiologically and to compare this with other currently used methods.

METHODS

Predissection computerized tomographic scans of 9 cadaver heads were used to delineate a novel line, the naso-axial line (NAxL), to predict the inferior EEA limit on the upper cervical spine. A previously described method with the use of the nasopalatine line (NPL or Kassam line) was also used. On computerized tomographic scans obtained following dissection of the EEA, the predicted inferior limits were compared with the actual extent of dissection.

RESULTS

The postdissection inferior EEA limit ranged from the dens tip to the upper half of the C2 body, which matched the limit predicted by NAxL, with no statistically significant difference between them. In contrast to the NAxL, the NPL predicted a significantly lower EEA limit (P < .001), ranging from the lower half of the C2 body to the superior end plate of C3.

CONCLUSION

The novel NAxL more accurately predicts the inferior limit of the EEA than the NPL. This method, which can be easily used on preoperative sagittal scans, accounts for variations in patients' anatomy and can aid surgeons in the assessment of the EEA to address caudal CVJ pathology.

Robotic Skull Base Surgery via Supraorbital Keyhole Approach

BACKGROUND:

The supraorbital keyhole approach has been used in anterior skull base tumor and aneurysm surgery. However, there are debates regarding the safety and limitations of this kind of approach.

OBJECTIVE:

To determine the feasibility and potential benefits of surgical robotic technology in minimally invasive neurosurgery.

METHODS:

Two fresh cadaver heads were studied with the da Vinci Surgical System with 0° and 30° stereoscopic endoscopes to visualize neuroanatomy. The ability of the system to suture and place clips under the keyhole approach was tested.

RESULTS:

The da Vinci Surgical System was used throughout the supraorbital transeyebrow keyhole approach. With the use of standard microdissection techniques, the optic nerve, optic chiasm, carotid artery, and third cranial nerve were visualized. The sylvian fissure was then exposed from the proximal sylvian membrane to the distal M1 segment. With the EndoWrist microforceps, suturing can be achieved smoothly to close a defect created on the M2 artery. Although the benefits in adjusting clips during aneurysm surgery could be provided by an articulating applier, a proper robotic applier is not currently available.

CONCLUSION:

The minimally invasive supraorbital keyhole surgery can be achieved with the da Vinci Surgical System in cadaver models. This system provides neurosurgeons with broader vision and articulable instruments, which standard microsurgical systems do not provide. Further studies are necessary to evaluate the safety and benefits of using the da Vinci Surgical System in minimally invasive neurosurgery.

Use of the da Vinci Minimally Invasive Robotic System for Resection of a Complicated Paraspinal Schwannoma With Thoracic Extension

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