The Contribution of CT Navigation in Endoscopic Sinus Surgery: an Evaluation of Patient Postoperative Quality of Life and Olfaction Function Results

Summary

Background and aim:
One of the most common indication of CT navigation surgery is the surgery of nasal sinuses and especially the revision surgery. The aim of this paper was to prove importance of surgical radicality of FESS on the improvement of quality of life and/or improvement of the sense of smell in particular surgical groups and on reduction of the number of revision surgeries.

Patients and Methods:
In the 5-year period between 2011 and 2015 in prospective study we performed a total of 374 navigated procedures (in 198 subjects) and 405 classical endoscopic endonasal paranasal operations (in 241 subjects). The decision about use of the CT navigation depended mostly on the quality of the CT scans. If the protocol used for the imaging allowed subsequent navigated procedure, then the navigation procedure was preferred. The quality of life was studied on a cohort of 439 patients as a prospective cohort study: on operated patients was the quality of life assessed using the SNAQ – 11 questionnaire (Sino nasal assessment questionaire - Czech version). The surgery was performed by a randomly selected surgeon from our rhinology group. For investigationg the olfactory function the Sniffin Sticks test was routinly used. The regularly postoperatiove follow-ups for our patients were scheduled in intervals of 1, 4, 12 weeks and 6 and 12 months in the first year after surgery, and later once to twice yearly.

Results:
We observed an improvement of 79% in quality of life, with a range from 72 to 83%. Olfactory deterioration is the most sensitive indicator of recurrent chronic rhinosinusitis. We reviewed the relationship between sense of smell and procedures performed both with and wihout the use of CT navigation. With surgical treatment, the sense of smell was maintained or improved in 86% of patients, while this figure reached only 55% in revision procedures.

We observed significantly better results with navigated surgery, at a ratio of 85% to 46%, regardless of whether a primary operation or revision was performed. In patients without allergies, the results with and without navigation were the same.

Conclusion:
Allergic patients operated with CT navigation had a significantly better sense of smell than patients operated by the endonasal method without CT assistance. The postoperative sense of smell in patients without allergies is comparable in both methods and all members of both groups had improved quality of life.

Keywords:
CT navigation, paranasal sinus, FESS, sense of smell, quality of life

INTRODUCTION

CT navigation is a modern instrumental method used to determine the exact position of anatomical structures during surgery on the basis of computerized preoperative CT images. CT navigation enables surgeon during the procedure to accurately locate various anatomical points and the position of their own tools within 3D images in three planes CT (3, 4, 21). It is an especially useful application in revision sinus surgery, in extensive nasal polyposis, in cases of damaged or altered anatomical structures of the nasal cavity and paranasal sinuses, with congenital defects, morphological anomalies of the nose and paranasal sinuses, in diseases of the skull base and orbit, in optic neuritis, and in tumors of the nasal cavity, paranasal sinuses, nasopharynx, skull base and ear (3, 4, 14, 17). Under certain conditions, it can also be used effectively in cases of tumors of the head and neck, in complications of inflammation of the paranasal sinuses and ear, and in maxillofacial trauma and injuries to the skull base (3, 5).

One of the most common indication of CT navigation surgery is the surgery of nasal sinuses and especially the revision surgery (7, 12, 14). Most of authors demonstrated merit of CT navigation for achievement of higher radicality and reduction of relapse of disease1 (1, 7, 12, 14). However reduction of complication frequency during surgery was not unambiguosly confirmed.

The success of treatment is evaluated using the subjective patients‘ rating (questionaire), endoscopic controls and the olfaction tests. Olfaction is very important for ingestive functions, avoidance of environmental hazards and social communication. (11).

AIMS

The aim of this paper was to prove importance of surgical radicality of FESS on the improvement of quality of life and/or improvement of the sense of smell in particular surgical groups and on reduction of the number of revision surgeries.

METHODS

In the 5-year period between 2011 and 2015 in prospective study we performed a total of 374 navigated procedures (in 198 subjects) and 405 classical endoscopic endonasal paranasal operations (in 241 subjects) (Graphs 1, 2). The quality of life was studied on a cohort of 439 patients as a prospective cohort study. The decision about use of the CT navigation depended mostly on the quality of the CT scans. If the protocol used for the imaging allowed subsequent navigated procedure, then the navigation procedure was preferred. The surgery was performed by a randomly selected surgeon from our rhinology group.

The most frequent diagnoses were chronic sinusitis (394), largely due to allergies (in 258 subjects i.e. 66%), polyposis and clinical symptoms of the lower airways. The male to female ratio of the total group was 1.9:1 and the age range was between 16 and 85 years, with a mean age of 43.2 years. The quality of life in operated patients was assessed using the SNAQ – 11 questionnaire (Sino nasal assessment questionaire - Czech version), which contains questions regarding olfaction, nasal patency, the presence of headaches, nasal secretions, sneezing, coughing, eye-pressure and sleep quality before and after surgery. Questionaire SNAQ-11 proved to be the best questionaire for postoperative follow-up of quality of life after FESS for its simplicity and equal information value compared to substantial longer and more complicated questionaires f.e. SNOT-20, SNOT-22 (2).

The regularly postoperatiove follow-ups for our patients were scheduled in intervals of 1, 4, 12 weeks and 6 and 12 months in the first year after surgery, and later once to twice yearly. We always performed the endoscopic endonasal investigation and evaluation of questionaire with focus on sense of smell. For investigationg the olfactory function the Sniffin Sticks test was routinly used. The deterioration of olfaction function correlated with relaps of chronic sinusitis. Advantage of this questionaire is its brevity, comprehensibility alongside the equal information value compared to substatially longer and more complicated questionaires – SNOT-20, SNOT-22 (Sinonasal outcome test) (2).

RESULTS

Of the 779 procedures (439 patients) performed for illnesses of the paranasal sinuses, 171 were revisions (22%), of which 120 were performed with CT navigation (15%) and 51 without navigation (7%). A combined approach (endonasal endoscopic and external) was required in 13 cases (2%), of which 5 were with CT navigation (0.6%).

The postoperative follow-up period for patients with chronic diseases of the paranasal sinuses ranged from 18 - 50 months and postoperative quality of life was assessed using the SNAQ – 11 questionnaire. Overall, we observed an improvement of 79% in quality of life, with a range from 72 to 83%. Due to the fact that the sense of smell is one of the basic human senses, we concentrated our research in this area. Olfactory deterioration is the most sensitive indicator of recurrent chronic rhinosinusitis. We reviewed the relationship between sense of smell and procedures performed both with and wihout the use of CT navigation. We evaluated the sense of smell in 176 subjects - 99 allergic patients and 77 non-allergic (Graphs 1, 2). These patients underwent smell tests repeatedly.

STATISTICAL EVALUATION

By statistical processing of correlations we evaluated a group of allergic and non-allergic patients indicated for larger endonasal sinus procedures with and without CT navigation. The results show that in patients with allergies, significantly better results were recorded during the investigating of sense of smell postoperatively, both in patients who underwent primary procedures and in those who had revision procedures. In nonallergic patients, the results were comparable in both groups. Results are summarized in Tables 1 and 2 and Graph. 3 and 4.

With surgical treatment, the sense of smell was maintained or improved in 86% of patients, while this figure reached only 55% in revision procedures.

However, when comparing individual subgroups of allergic patients, we observed significantly better results with navigated surgery, at a ratio of 85% to 46%, regardless of whether a primary operation or revision was performed. In patients without allergies, the results with and without navigation were the same.

DISCUSSION

The use of CT navigation during surgical procedures in otorhinolaryngology is relatively common, and the method is still developing. The first mention of the use of CT-guided surgery in otorhinolaryngology in international literature appears in Gunkel et al. in 19953 (4). Vokurka and Sičák were the first Czech and Slovak authors interested in the field (15, 21).

In line with our results, Al Swiahb et al. recorded a decrease in postoperative complications from 3.3% to 0% and noted a decline in paranasal disease from 37% to 17% (1). Schmerber evaluated positively the contribution of navigated paranasal surgery with complex anatomy, especially in revision surgery (14).

Chiu and Vaughan highlight the benefits of CT - assisted surgery in endonasal endoscopic frontal sinus revisions, and their views are in line with our findings (7, 17).

Strauss indicates that navigation leads to a reduction in the operating time and reduces surgeon stress during the procedure (18).

Manzey states that 90% of FESS performed in Germany is done under the CT navigation assistance for better space orientation, 45% surgeon’s stress reduction and for over than two thirds better surgical results (12).

Stelter commeds CAS for education of young surgeons (16).

However, some authors (from USA and Switzerland) demonstrate no improvement in clinical results with CT navigation and point only to reduced postoperative complications from its use (13, 19, 20).

The best accuracy of the navigation system is achieved using the collection of surface point by the registration probe (6).

Recently, there has been an increase in the use of CT navigation in the treatment of ocular complications of rhinosinusitis, a point which Ketenci also makes in international literature (10). Among Czech authors dealing with this issue are Kastner et al. (9) and Holy et al. (5).

Javer’s paper indicates that according to the quality of life questionnaire (RSOM) completed by a group of 95 patients, there is a significant improvement in quality of life, in contrast to the patient group operated without navigation (8).

According to our findings, allergies affect operating results, even when treated per normal standard of care (with topical corticosteroids, antihistamines).

Knizek et al. state that changes in olfactory fiction in patiens with chronic rhinosinusitis after surgery are hard to predict. Their results show that nasal polyps, asthma, lower age and higher Lund-Mackay score are factors which predict better postoperative outcome (11).

CONCLUSION

The postoperative sense of smell in patients without allergies is comparable in both methods and all members of both groups had improved quality of life. Allergic patients operated with CT navigation had a significantly better sense of smell than patients operated by the endonasal method without CT assistance

Each revision surgery reduces the chance of postoperative olfactory improvement. Of key importance in the outcome for the patient is the primary operation, in particular its accuracy and scope, especially in allergic patients. The results from our 5-year follow up period suggest that the use of CT navigation is able to minimize the number and extent of complications, even when operating under difficult anatomical conditions.

All paranasal revision surgery should be performed by an experienced surgeon, ideally using CT navigation.

Acknowledgements: This work was supported by grant projects of Ministry of Health of the Czech Republic 15-32791A and the Ministry of Defence of the Czech Republic MO 1012.

Conflicts of interest: The authors state that there are no conflicts of interest regarding the publication of this article.

Adresa ke korespondenci:

As. plk. MUDr. Daniel Kovář

Klinika ORL 3. LF UK a

ÚVN Praha

U Vojenské nemocnice 1200

169 02 Praha 6

e-mail: daniel. kovar@uvn.cz