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|NI FEATURE: TECHNOLOGY INNOVATIONS
|Year : 2019 | Volume
| Issue : 6 | Page : 1509-1512
Development of a Unique Retractor for Performing Endoscopic Pituitary Surgery-EASYTRAC
P Sarat Chandra, Kiran Deep Kaur
Department of Neurosurgery, All India Institute of Medical Sciences, New Delhi, India
|Date of Web Publication||20-Dec-2019|
Dr. P Sarat Chandra
Professor and Head of Unit 1, Dept. of Neurosurgery, AIIMS, New Delhi - 110 029, India. E-mail: firstname.lastname@example.org
Source of Support: None, Conflict of Interest: None
Background: A unique self-expanding retractor (EASYTRAC®) is described, which provides several advantages for endoscopic pituitary surgery-enhanced visualization, creating more space, reducing the mucosal damage, and enhancing the nasal quality of life (QoF). Presented here is the proof of concept.
Methods: EASYTRAC® is made of an aircraft-grade, SS-titanium alloy to provide optimal opening strength with a low profile (0.5 mm thick). It has a nonreflective, smooth surface finish. Patented design and wire pulling method of the EASYTRAC® makes it easy to insert and deploy. EASYTRAC® is inserted through the submucosal tunnel using a small, unilateral mucocutaneous incision. Following this, the ring attached to the wire is pulled out to deploy the retractor. This provides expansion of the retractor leading to fracture of the septum to one side at the keel of the vomer. The rest of the surgery is performed in the standard manner using an endoscope. The retractor is a single-use, disposable instrument and available in three different sizes.
Results: Five endoscopic endonasal surgeries have been performed using the EASYTRAC®(four pituitary adenomas, one craniopharyngioma). Deviated nasal septum (DNS) was present in two of the surgeries. All surgeries were approached through the right mucoseptal corridor, and presence of DNS did not reduce exposure (<10 minutes for exposure). No hardware problem was observed in any of the cases. Intraoperative cerebrospinal fluid (CSF) leak (n = 1) was managed with intraoperative, standard, triple-layer closure with glue and lumbar drain.
Conclusion: Retractor seems to be safe, easy to use, and effective. The surgeon's capabilities are enhanced by the retractor's dynamicity, minimal fogging of scope, minimal trauma to the mucosa, and adequate space to allow the introduction of three instruments through a single nostril.
Keywords: Endoscope, pituitary, retractor, surgeryKey Message: A unique patented self expanding, dynamic, low profile retractor for endoscopic, endonasal surgeries, especially for pituitary tumours is described.
|How to cite this article:|
Chandra P S, Kaur KD. Development of a Unique Retractor for Performing Endoscopic Pituitary Surgery-EASYTRAC. Neurol India 2019;67:1509-12
Authors contributed in designing the concept, data collection and manuscript preparation.
Author helped in writing the patent.
Endoscopic endonasal surgery has become the standard procedure for pituitary adenomas.,,,,,,, Extended approaches have provided optimal and minimally invasive approaches to pathologies like craniopharyngioma and chordomas and (less frequently) to other pathologies.,,, However, this procedure is frequently associated with morbidity-related mucosal and nasal damage., This is especially true for binostril approaches, posterior nasal septum excisions, and situations where partial or complete turbinectomies are performed. In addition, many neurosurgeons take the help of ear, nose, and throat (ENT) surgeons (or an experienced assistant) to provide guidance with the endoscope as well as access to the nasal corridor. The standard procedure also involves repeated removal and insertion of the endoscope and frequent cleaning and defogging of the rod lens system. In addition, because of space constraints, it is difficult to insert three instruments (e.g., endoscope, suction, and bipolar) through the same nostril; hence, a binostril approach is often used. Understanding these limitations, the senior authors worked to develop a unique, low-profile, expandable dynamic retractor. The concept, design, and its advantages are briefly described here.
| » Methods|| |
The retractor (commercially named as EASYTRAC ®, patent number R20191028780) consists of a V-shaped, long-folded, and compressed construct [Figure 1]. The open ends of the V are stuck to each other and maybe released by a cutting wire attached to the ring, which is pulled out to release and deploy the retractor once it is placed in position. There are three different sizes of the retractor to allow it to be used in pediatric (10 mm × 100 mm), small (15 mm × 150 mm), and large adults (20 mm × 150 mm). These sizes were selected after measuring the size of nasal cavities on over 50 normative magnetic resonance (MR) images. The closed end of the “V” is positioned at the 12 o'clock position. EASYTRAC ® is made of aircraft-grade, SS-titanium alloy to provide optimal opening strength while maintaining a low profile (0.5 mm thick). The retractor is coated with black color to provide a nonreflective and smooth surface finish. Multiple heat treatments have been provided to ensure spring action and the optimal opening strength of the retractor. The patented design and wire pulling opening method of the EASYTRAC ® makes it easy to insert and deploy. Once the retractor is introduced, the ring attached to the wire is pulled out to deploy the retractor. This provides expansion of the retractor leading to fracture of the septum at its junction with the keel of the vomer. The endoscope then is introduced along the apex of the “V.”
|Figure 1: (a and b) show the design of the retractor. As described, it consists of a long “V”-shaped construct folded upon itself, which is released and deployed by pulling the wire with the ring. This releases the tensile spring mechanism leading to the opening of the blades of the retractor (also see Figure 2). (c) shows the submucosal tunnel created on the right side of the nasal septum (arrow). (d) shows the black nonreflective blades over the keel of the vomber after they have opened and fractured the septum to one side and exposed the keel of Vomer. (e) shows the 1 mm Kerrison “down cut” (arrow) passing from the sphenoid ostium (marked as “sph ostium'). Note how comfortably the retractor has created space for three instruments. (f) shows the tumor removal|
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The patient is placed under general anesthesia (GA), prepared and put in the supine position as in any standard endoscopic and endonasal procedures. It is preferred that the nasal cavity is examined endoscopically on both sides before placing the incision. A small incision is placed in the anterior-posterior direction over the septal mucocutaneous junction on the right side (See video: https://m.youtube.com/watch?v=OG_2O4fTEPY&t=9s). Using a No. 2 Penfield dissector, a mucoseptal tunnel is created on the right side until the keel of the vomer. Care should be taken not to fracture the septum. The trajectory may be crosschecked with the use of image intensifier or neuronavigation. A standard suction cannula is then introduced inside to slowly separate the blades of the retractor further. The blades slowly strip the mucosa further to create a spacious submucosal tunnel (See video: https://m.youtube.com/watch?v=OG_2O4fTEPY&t=9s). The spring action between the blades holds it apart. Distally, the blades strip to expose the keel of the vomer and sphenoid ostia on both sides (owl's eye). Unlike the standard metallic retractors like Hardy's speculum, this retractor may be used dynamically, i.e., be used to visualize the lateral structures like the medial and lateral cavernous sinus. Likewise, they may be also used to visualize the planum and upper clivus. However, the author would currently advise its use only for standard sellar approaches. Once the keel of the vomer is exposed, a 1 mm Kerrison (down cut) is used to make a cut on the floor of sphenoid sinus on either side starting from sphenoid ostium in a superior–inferior direction. A small chisel may be used to join these two cuts at the base. The whole vomer along with the floor of the sphenoid sinus may be removed in toto. Unlike, Hardy's speculum, if the surgeon so wishes, he/she may pass the retractor into the sphenoid sinus without the fear of causing optic canal strut fracture. The rest of the surgery is like any other standard endoscopic surgery. The assistant can move the endoscope in an “in and out” motion as per the requirement of the surgeon. With the protection of the retractor on either side of the endoscope, the incidence of fogging of endoscope reduces significantly. This again significantly reduces the duration of surgery, which is otherwise spent in cleaning the scope. Once the surgery is over, the EASYTRAC ® may be pulled out. If required, the glue may also be injected into the submucosal tunnel to allow adequate opposition of mucosa to the bony septum. Using the index finger, the septum is brought to the midline and a single vicryl 3-0 suture is used to close the mucosal opening. The author did not use nasal tampons in cases without cerebrospinal fluid (CSF) leak, but they may be used in cases where a triple graft repair was performed.
| » Results|| |
We performed five endoscopic endonasal surgeries using EASYTRAC ® to test its ease of use and efficacy (four pituitary adenomas, one craniopharyngioma). All the pituitary adenomas were macroadenomas, of which two were functional, one was acromegaly, and another had gigantism. The latter patient was an 18-year-old boy (height of 6 ft 8 in) and required the largest size of the retractor [Figure 2]. The patient with craniopharyngioma had a deviated nasal septum (DNS) that was present in four other cases. All the patients were approached through the right mucoseptal corridor and DNS did not reduce the exposure (<10 min for exposure). The intraoperative CSF leak in craniopharyngioma was managed with an intraoperative, standard, triple-layer closure (inlay fascia lata, fat, and fascia again) and glue along with the lumbar drain. In none of the cases, there was any need to remove the retractor or convert it into a microscopic surgery. Total removal was performed in all cases. The average time taken for surgery was 48 ± 18 min. The time taken to reach the keel of vomer was not more than 10 min, and with experience, it reduced to 3–4 min. Post-operatively, patients had minor nasal congestion and were started on oral feeds the next morning. Day one onward the nasal cavities were patent (as per the test by breathing on a metal spatula and nasal examination).
|Figure 2: (a) shows the manner in which the retractor passes through the nostril. The assistant can use one hand to open the blades. As may be seen, the endoscope may be passed along the 12 o'clock position of the retractor. (b) shows the three sizes of the retractor. The diagram also shows the wire with the ring, which may be pulled to deploy the retractor. (c) shows the used retractor (large size). Notice the small footprint, yet the optimal tensile strength, which is present to keep the blades open|
Click here to view
| » Discussion|| |
The current standard technique involves the direct introduction of the endoscope into the nasal cavity, lateralization of the middle turbinate, and entering through the sphenoid ostium. This is often combined with excision of the posterior part of the nasal septum, followed by an instrument introduction through the opposite nostril. While this has emerged as a standard surgical procedure, there are several shortcomings of this technique. Some of which are mentioned below.
- Mucosal damage: The amount of mucosal debridement is significant, more than what the surgeons would usually like to admit. Surgeons with lesser experience often prefer to perform partial or complete turbinectomies. This is especially true in cases where the turbinates are unusually large or associated with severe DNS. Likewise, many surgeons prefer to create surgical access through both nostrils by excising the posterior part of the nasal septum. This again leads to the disproportionate removal of nasal mucosa and structures. Complications of mucosal debridement leading to loss of septum, atrophic rhinitis, crusting, etc., are often undermined in various surgical series
- Requirement of an experienced second assistant: Endoscopic surgeons have often emphasized the need for an experienced second assistant (preferably an ENT surgeon or assistant surgeon), who can help the neurosurgeon gain access to the sella and adjacent dura. This need has arisen because ENT surgeons are more familiar with nasal anatomy. While this may be true for lateral skull base approaches, most of the midline approaches require following a straightforward trajectory, which is usually familiar to neurosurgeons. In addition, increasing the number of team members unnecessarily adds to the health care cost
- Shortcomings because of less space: While the nasal cavity is a physiological corridor to access the sella, it is not designed to hold multiple instruments. Likewise, the constraints of the space require frequent removal, cleaning, and reinsertion of the endoscope. Prolonged surgery again leads to mucosal swelling, congestion, and a reduction in the volume of the space. In addition, less space leads to many surgeons preferring a binostril approach, again leading to more mucosal damage.
Advantages of EASYTRAC®
The advantages of EASYTRACK ® have already been discussed above. To briefly summarize, the retractor helped in creating optimal space to allow the introduction of three instruments through a single nostril. The introduction of the retractor is easy using the uniseptal, submucosal approach. While the author has not used the retractor endonasally, it could be used to lateralize the turbinate for an endonasal approach, if so required. The author has observed that using a submucosal, transseptal approach  causes minimum damage to the mucosa and may contribute toward a superior nasal quality of life (QoL).
The objective of the current study was to describe the design, construct, and technique of surgery using the EASYTRAC ® retractor and test its efficacy.
| » Conclusion|| |
EASYTRAC ®, in its preliminary use, has shown to be effective, easy to use, and provides excellent space within the uninostril corridor. It preserves the integrity of the nasal mucosa and can be easily introduced and deployed. The author currently has used it for standard pituitary adenomas and a large craniopharyngioma.
Financial support and sponsorship
Nil. The concept, design of EASYTRAC ® was designed by the senior author along with Walnut Medical after due permission as it is still in process from the Patent section, AIIMS, Delhi.
Conflicts of interest
There are no conflicts of interest apart from what has been mentioned above.
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[Figure 1], [Figure 2]