Abstract
Objective
To study the long-term radiological findings after endonasal endoscopic approach to the skull base.
Material and methods
Prospective study that included 55 patients who underwent advance endoscopic skull base surgery. All patients were evaluated with MRI before, 3 months and 12 months after surgery. We used the Lund–Mackay staging system for chronic rhinosinusitis to evaluate the paranasal cavities and the sinonasal scoring system to assess sinonasal symptoms.
Results
Seventeen patients (30.9%) underwent extended endonasal approach that required a nasoseptal flap (NSF) for reconstruction of skull base. At baseline the mean total Lund–Mackay score was 0.63 ± 1.2 (range 0–4), and at 3 and 12 months postoperatively the mean scores were 3.5 ± 3.8 (range 0–14) and 2.0 ± 2.5 (range 0-8) respectively. Patients who needed an NSF for reconstruction had a greater Lund–Mackay score (p < 0.05). Moreover, NSF is correlated with sinonasal mucosal thickening and fluid retention at 3 months (r = 0.45, p < 0.01) and 12 months (r = 0.4, p < 0.01). Total 5-symptom score (T5SS) was similar between both groups at baseline. Patients with extended endoscopic approach reported more smell loss (40.1 ± 26.2; p < 0.05) and posterior nasal discharge (49.3 ± 30.1; p < 0.05) than TTEA patients (21.6 ± 30.9 and 22.5 ± 27.5 respectively).
Conclusions
We observed that sinus opacity is still present after one year of advance endoscopic skull base surgery but symptoms seems to return to basal after 12 months of follow-up.
1
Introduction
In the last decade there has been a significant increase in the use of transnasal endoscopic approaches to treat skull base tumors. Moreover, outcomes of transnasal endoscopic approaches had comparable short-term results with microscopic or open approaches . This rapid development could be explained because of the better understanding of endoscopic anatomy, the advancement of imaging systems and specific instruments to these approaches, and the use of vascularized flaps for reconstruction of the skull base . As in endoscopic sinus surgery, extended approaches will cause a series of postoperative morbidities such as crusting and posterior rhinorrhea, especially when a nasoseptal flap is necessary for skull base reconstruction . Generally when there is a mechanical damage to the sinus mucosa the epithelialization by stratified respiratory epithelium occurs in a week, the ciliary cells appear in the third week and complete recovery of sinus epithelium occurs between 6 and 8 weeks . Based on this fact, Ginzel and Illium conclude that one should wait at least three months after surgery to assess the clinical and postoperative symptoms. Balaker et al. showed that transnasal endoscopic approaches to skull base had clinical consequences such as persistently elevated postnasal discharge and a reduced sinonasal quality of life (QoL). Concerning post-surgical quality of life, Georgalas et al. have found that the negative impact of nasoseptal flap on quality of life is mainly due to headaches and smell loss, but these symptoms improve with time, especially in patients with pituitary secretory tumors. Alobid et al. showed that extended endonasal approaches (EEA) but not transnasal transsphenoidal endonasal approaches (TTEA) have a short-term (3 months) negative impact on patient’s olfaction and mucociliary clearance, but failed to found differences between secretory and non-secretory pituitary tumors.
There are very few studies on postoperative radiological characteristics of the patients undergoing extended skull base surgery. For this reason, the aim of this study is to characterize the sinonasal consequences of endonasal approaches to the skull base, and assess the postoperative radiological findings in an effort to better understand the morbidity associated to this approaches.
2
Material and methods
2.1
Study population
Between January 2009 and January 2013, adult patients (≥ 18 years old) diagnosed with pituitary or benign skull base tumors were enrolled to undergo in this prospective study. Patients were divided in two groups; the first group underwent TTEA and the second group had an EEA. Patients with past history of pre-existing subjective smell disturbance, chronic rhinosinusitis, intranasal drug abusers or sinonasal/skull base malignancy were excluded. The Ethics Committee of Hospital Clínic de Barcelona approved the study and signed informed consent was obtained from all patients.
2.2
Study design
Assessment of sinonasal radiological findings and sinonasal symptoms was performed on all patients before, 3 months and 12 months after surgery. Ohashi et al. reported that complete healing of the nasal mucosa after trauma may occur after a postoperative period of 5 days. When the entire nasal mucosa was damaged, regenerative epithelium covered the defect in one week, new ciliated cells appeared in 3 weeks, and complete regeneration was observed at 6 weeks. Based on these findings, we decided to wait at least 3 months for full recovery of nasal mucosa in order to evaluate postoperative symptoms and radiological findings.
2.3
Radiological findings
An MRI Lund–Mackay score (LMS) was used to grade mucosal thickening and fluid accumulation. In the LMS scoring system, a score of 0 was defined as normal mucosa without any thickening, a score of 2 was assigned to any sinus with complete opacification, and a score of 1 was given to sinuses demonstrating any mucosal thickening without complete opacification. The ostiomeatal complex was scored as either 0 (not obstructed) or 2 (obstructed). The unilateral results range from 0 to 12 points and total score (both sides) from 0 to 24 points.
2.4
Sinonasal symptoms
Patients were asked to score their sinonasal symptoms (nasal obstruction, facial pain or pressure, anterior and posterior nasal discharge, and loss of smell) using a Visual Analogue Scale (VAS, 0 to 100 mm) and total symptoms score (TSS5, 0 to 500) was calculated. Sinonasal symptoms were scored as: 0 = no symptoms, 0–200 = mild, 201–400 = moderate, > 400 = severe symptoms.
2.5
Surgical procedures
2.5.1
TTEA
The middle turbinate was gently bent laterally to allow access to the sphenoid ostium. The nasal mucosa overlying the anterior sphenoid wall and vomer was cauterized in order to create a wide sphenoidotomy. The mucosa of the sinus was removed to prevent postoperative bleeding and late mucocele formation. The dura of the sella was adequately exposed to remove the tumor. A vascularized flap was not used, and postoperative nasal packing was not routinely used.
2.5.2
EEA
Middle turbinectomy was performed in the majority of patients, and resection of the posterior third of the superior turbinate was required in some cases, to improve the surgical field. An ethmoidectomy and a wide sphenoidotomy with resection of the posterior part of the septum were performed to achieved a better access and identify anatomical landmarks within the sphenoid bone. In fact, the exposure through an extended approach was “tailored” depending on surgical pathway, type, tumor size and shape, and relationship with the surrounding neurovascular structures. The vascularized septal flap (VSF) was designed according to the size and shape of the anticipated defect. Two parallel incisions using a cutting electrocautery on a low-power setting were performed following the sagittal plane of the septum. One incision followed the maxillary crest and nasal floor, whereas a parallel incision thru a line 1 cm below the superior aspect of the septum (olfactory sulcus). These parallel incisions were joined anteriorly by a vertical incision. Posteriorly, the superior incision was extended laterally to cross the rostrum of the sphenoid sinus. The inferior incision extended following the edge of the posterior septum. Laterally crossing the posterior choana just below the floor of the sphenoid sinus. We usually store the flap in the nasopharynx or maxillary sinus depending on the tumor localization.
Reconstruction main objective is to prevent complications mostly related to postoperative cerebrospinal fluid leakage. One single large layer of dural substitute was positioned in the extradural space between the dura and the surrounding bone to provide a watertight closure. Then the vascularized mucosal flap was used to cover the skull base reconstruction and the previously denuded surrounding bone. Anterior nasal packing was maintained 24 to 48 h after surgery.
2.6
Statistical analysis
Statistics were performed with the SPSS 20.0 (SPSS, Chicago, IL, USA) software. The data are presented as mean ± standard deviation. The postoperative and preoperative LMSs were compared using the Wilcoxon signed-rank test by sinus location and total score. Pearson correlation coefficients were used to examine the association between sex, age and nasal symptoms. U Mann–Whitney test was done to compare the mean values between the surgical approaches. A P value of less than 0.05 was considered statistically significant.
2
Material and methods
2.1
Study population
Between January 2009 and January 2013, adult patients (≥ 18 years old) diagnosed with pituitary or benign skull base tumors were enrolled to undergo in this prospective study. Patients were divided in two groups; the first group underwent TTEA and the second group had an EEA. Patients with past history of pre-existing subjective smell disturbance, chronic rhinosinusitis, intranasal drug abusers or sinonasal/skull base malignancy were excluded. The Ethics Committee of Hospital Clínic de Barcelona approved the study and signed informed consent was obtained from all patients.
2.2
Study design
Assessment of sinonasal radiological findings and sinonasal symptoms was performed on all patients before, 3 months and 12 months after surgery. Ohashi et al. reported that complete healing of the nasal mucosa after trauma may occur after a postoperative period of 5 days. When the entire nasal mucosa was damaged, regenerative epithelium covered the defect in one week, new ciliated cells appeared in 3 weeks, and complete regeneration was observed at 6 weeks. Based on these findings, we decided to wait at least 3 months for full recovery of nasal mucosa in order to evaluate postoperative symptoms and radiological findings.
2.3
Radiological findings
An MRI Lund–Mackay score (LMS) was used to grade mucosal thickening and fluid accumulation. In the LMS scoring system, a score of 0 was defined as normal mucosa without any thickening, a score of 2 was assigned to any sinus with complete opacification, and a score of 1 was given to sinuses demonstrating any mucosal thickening without complete opacification. The ostiomeatal complex was scored as either 0 (not obstructed) or 2 (obstructed). The unilateral results range from 0 to 12 points and total score (both sides) from 0 to 24 points.
2.4
Sinonasal symptoms
Patients were asked to score their sinonasal symptoms (nasal obstruction, facial pain or pressure, anterior and posterior nasal discharge, and loss of smell) using a Visual Analogue Scale (VAS, 0 to 100 mm) and total symptoms score (TSS5, 0 to 500) was calculated. Sinonasal symptoms were scored as: 0 = no symptoms, 0–200 = mild, 201–400 = moderate, > 400 = severe symptoms.
2.5
Surgical procedures
2.5.1
TTEA
The middle turbinate was gently bent laterally to allow access to the sphenoid ostium. The nasal mucosa overlying the anterior sphenoid wall and vomer was cauterized in order to create a wide sphenoidotomy. The mucosa of the sinus was removed to prevent postoperative bleeding and late mucocele formation. The dura of the sella was adequately exposed to remove the tumor. A vascularized flap was not used, and postoperative nasal packing was not routinely used.
2.5.2
EEA
Middle turbinectomy was performed in the majority of patients, and resection of the posterior third of the superior turbinate was required in some cases, to improve the surgical field. An ethmoidectomy and a wide sphenoidotomy with resection of the posterior part of the septum were performed to achieved a better access and identify anatomical landmarks within the sphenoid bone. In fact, the exposure through an extended approach was “tailored” depending on surgical pathway, type, tumor size and shape, and relationship with the surrounding neurovascular structures. The vascularized septal flap (VSF) was designed according to the size and shape of the anticipated defect. Two parallel incisions using a cutting electrocautery on a low-power setting were performed following the sagittal plane of the septum. One incision followed the maxillary crest and nasal floor, whereas a parallel incision thru a line 1 cm below the superior aspect of the septum (olfactory sulcus). These parallel incisions were joined anteriorly by a vertical incision. Posteriorly, the superior incision was extended laterally to cross the rostrum of the sphenoid sinus. The inferior incision extended following the edge of the posterior septum. Laterally crossing the posterior choana just below the floor of the sphenoid sinus. We usually store the flap in the nasopharynx or maxillary sinus depending on the tumor localization.
Reconstruction main objective is to prevent complications mostly related to postoperative cerebrospinal fluid leakage. One single large layer of dural substitute was positioned in the extradural space between the dura and the surrounding bone to provide a watertight closure. Then the vascularized mucosal flap was used to cover the skull base reconstruction and the previously denuded surrounding bone. Anterior nasal packing was maintained 24 to 48 h after surgery.
2.6
Statistical analysis
Statistics were performed with the SPSS 20.0 (SPSS, Chicago, IL, USA) software. The data are presented as mean ± standard deviation. The postoperative and preoperative LMSs were compared using the Wilcoxon signed-rank test by sinus location and total score. Pearson correlation coefficients were used to examine the association between sex, age and nasal symptoms. U Mann–Whitney test was done to compare the mean values between the surgical approaches. A P value of less than 0.05 was considered statistically significant.
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