Role of computer aided navigation system for surgical treatment of extensive sinonasal polyposis

INTRODUCTION

Otolaryngological surgeries have gone beyond the sinuses. Operating near the important vital structures like orbit, carotid arteries, sometimes become a challenge to the surgeon when landmarks cannot be identified. Lesions like extensive sinonasal ethmoidal polyposis, benign lesion like inverted papilloma can be difficult to excise completely because of absence of landmarks due to destructive pathology. The computer aided surgery is more helpful in revision FESS, frontal sinus disease, sphenoid sinus lesions and extensive polypoid lesions.¹ The vital structures like optic nerve, Internal carotid artery, cavernous sinus and their variability of the anatomy around the sphenoid sinus make image-guided sphenoid surgery an important adjunct to safety.²

The comfort level of surgeon is very poor in such cases. In this regard, the navigation surgery is very helpful and increases the disease clearance adequacy, decreases the rate of complications.³ The navigational system is more precise and makes the surgeon more confident.⁴

The knowledge about anterior and lateral skull base has been increasing and likewise, skull base surgeries like CSF rhinorrhoea, sphenoid lesions, pituitary tumours are more and more treated.

The availability of computer aided navigational system is attracting otolaryngologists as the equipment has state of the art high grade medical monitor depicting CT scan sectional views and endoscopic views; it becomes an excellent teaching aid for learning and demonstration. Hence dissipation of knowledge can occur to surgeons, fellows, post graduates, and under graduates.

METHODS

A prospective study of all patients with extensive nasal polypoid lesions attending outpatient section of department of ENT, BLDE (DT) University’s Sri BM Patil Medical College and Research Centre, Vijaypur, was done from date January 2015 to December 2017.

Inclusion criteria were those who had extensive sinonasal polyposis as evidenced by CT scan of paranasal sinuses involving at least two or more sinuses and nasal cavities. Those cases of malignancy of nose and paranasal sinuses and who cannot come for follow-up were excluded.

A total of 75 patients were selected for this image guided surgery. All patients were subjected to detailed history including SNOT-22 Scoring after informed consent.⁵ Randomly 37 Patients were selected for navigation guided surgery and 38 patients were selected for endoscopic surgery without navigation. Institutional ethical clearance was taken for the research and consent received from all the patients.

For patients chosen for navigation, Preoperatively CT Scan with navigation protocol and necessary investigations were done. All patients underwent general anaesthesia. The patient was registered with navigation equipment (ENT Fusion navigation System, Meditronic) as per guidelines. The whole procedure was done under navigation guidance with endoscopic surgery and microdedrider for polypectomy. Except for navigation protocol CT, the same above steps are done for without navigation group.

During the surgery, disease clearance adequacy, Surgeon’s comfort level and number of major and minor complications were noted.

Each data was recorded and analysed for significance and p value at 95% confidence interval. The statistical analysis was done using SPSS software version 20.

RESULTS

The age of the patients ranged from 9-76 years. The distribution of sex is given in Table 1. The symptoms of the patients were studied according to SNOT-22 scores preoperatively and postoperatively and given in Table 2.

For the navigation group, preoperatively, it was found to be a mean of 41.05 with SD OF 5.46. Post operatively SNOT scores were 27.11, 23.89, 23.53 (SD of 5.7, 5.65, 5.8) on the 3^rd day, on 1 month and 3^rd month respectively. These values were significant with p<0.001.

For without navigation group, preoperatively, it was found to be a mean of 35.42 with SD of 2.94. Post operatively SNOT scores were 28.26, 23.89, 25.5 and 23.92 (SD OF 4.7, 3.70 and 3.78) on the 3^rd day, on 1 month and 3^rd month respectively. These values significant at 5% level of significance (p<0.001).

Note: *significant at 5% level of significance (p<0.05).

The comfort level of the surgeon was noted for each surgery as good in 89.18%, medium in 10.8% and bad in 0% cases in navigation guided surgeries. Whereas in surgeries without navigation, it was good in 78.9%, medium 10.52% and bad in 10.52% cases. The following Table 3 gives the details.

Intraoperatively disease clearance adequacy measured as partial in 1 case (2.7%) and total in 36 cases (97.3%).

In case without navigation, the scores were 4 (10.5%) partially cleared, 34 (89.5%) cases were totally cleared.

Figure 1 and 2 represents a case of mucourmycosis which presented as extensive sinonasal polyposis and because of navigation aided surgery, it could be cleared.

Intraoperatively disease clearance adequacy measured as partial in 1 case (2.7%) and total in 36 cases (97.3%). In case without navigation, the scores were 4 (10.5%) partially cleared, 34 (89.5%) cases were totally cleared. These are recorded in Table 4.

During the study, we encountered zero major (0%) and one minor complication, 1 (3%) in surgery with navigation. In group without navigation guided surgery, Major complication was 13% and minor was 11%. These values are indicative of P value was 0.021 which suggests significant less major complications in the group with navigation guided surgery.

Figure 3 show the case of extensive nasal polyposis which went for severe bleeding intraoperatively but the case could be completely cleared (Figure 4) despite the bleeding.

Note: *significant at 5% level of significance (p<0.05).

DISCUSSION

The objective of this research is to study the role of navigation guided endoscopic sinus surgeries in extensive ethmoidal polyposis by comparing surgeries with and without navigation.

This image guided surgery is useful in specific diseases like extensive sinonasal polyposis, mucourmycosis, frontal sinusitis, the sphenoid sinusitis and the lesions of sphenoethmoid regions, the posterior ethmoidal disease etc.^1,3,6 It can be used in those who have had previous surgery with distorted anatomy and those with bone eroding disease and intraorbital or extradural lesions.

Jamil and colleagues undertook a study of 60 randomly chosen patients with chronic rhinosinusitis (CRS) and moderate-to-severe sinonasal polyposis, undergoing endoscopic sinus surgery with surgical navigation (CAS) (n=30) and without navigation (non CAS) (n=30). They studied for data on the operative note, time of surgery, complications, and recurrence rate. They found significant improvement in the recurrence rate (n=11, 36.7% in the non-CAS group; n=5, 16.7% in the CAS group), and intraoperative complications were fewer in the CAS group (two exposures of orbital fat in the non-CAS group; no complications in the CAS group). They concluded that computer aided navigation surgery is a good adjunt for endoscopic sinus surgeries.⁴

In our study, the operative time was prolonged to an extent of 15-20 minutes, whereas 13 minutes was the operative period in cases of Jamil and colleagues.⁴

Kacker et al, studied 85 patients of revision sinus surgery under navigation. In his cohort, no complications occurred although we had minor complications in 3% in navigation guided surgeries.⁷

In a meta-analysis of 105 articles, Lanza and his colleagues.⁸ pointed out that most of them reported reduced risk of complications or no significant difference. He is of the opinion that large cohorts like 3000 or above per group are required to show relevant results.

Our study showed number of major and minor complications 11% and 13% in surgeries without navigation and 0% and 3% with navigation respectively. Occurrence of complications can be studied if sample is more than 3000 as per Lanza et al.⁸

Yi et al concluded that when the surgical field has been distorted by prior surgery, inflammation or disease, Computer-aided endoscopic sinus surgery is extremely helpful for safety of the patient and represents state-of-the-art technology.⁹

The image guided surgery is expected to facilitate more precision during surgery. It has less risk of complication for the patient both intraoperatively and postoperatively.³ It allows more complete surgical dissection. It also reduces recovery period.

Limitations

The limitations are mainly the size of our sample. Many other factors like differences in operative time of surgeries with or without navigation, confidence level and learning curve for juniors could have been studied.

CONCLUSION

The reduced incidence of complications during surgery with navigation, improved disease clearance adequacy, good comfort level of surgeon and significantly improved symptom scores prove that the computer aided navigation guided surgery is a necessary tool in cases of extensive lesions like sinonasal polyposis.

ACKNOWLEDGEMENTS

Author thanks Mulimani BG (Ex vice chancellor), Biradar MS (vice chancellor BLDE (DU)’s Shri BM Patil Medical College), Guggarigoudar SP (Principal) and Commtttee of Vision group of science and technology, Karnataka.

Funding: Partly from Vision group of science and technology, Karnataka and BLDE (DU)’s Shri BM Patil Medical College, Hospital and Research Centre, Vijayapur, Karnataka, India

Conflict of interest: None declared

Ethical approval: The study was approved by the Institutional Ethics Committee of BLDE (DU)’s Shri BM Patil Medical College, Hospital and Research Centre, Vijayapur, Karnataka, India

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