Balloon catheter dilation (BCD) is a treatment paradigm for surgical management of paranasal sinus inflammatory disease. There are few robust clinical trials evaluating the efficacy of balloon technology in chronic rhinosinusitis (CRS). The available database largely comprises retrospective, uncontrolled studies with insufficiently characterized patient cohorts and a lack of comparator groups. Thus, the current evidence base is unable to elucidate the role and indications for BCD in the management of medically refractory CRS. Future studies should include selected control groups, preferably with randomization and validated outcome measures, to determine the efficacy of balloon technology compared with endoscopic sinus surgery.
The following points list the level of evidence as based on Oxford Center for Evidence-Based Medicine. Additional critical points are provided and points here are expanded at the conclusion of this article.
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Numerous studies have evaluated the usefulness of balloon catheter technology for surgical management of adult CRS, with overarching existing data deemed to be level 4.
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One study reporting the use of BCD for frontal sinus disease provides level 2b evidence, suggesting possible usefulness of the technology for this indication.
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Level 4 evidence is available for the use of BCD in the office and intensive care unit setting, although both may represent potentially important applications of balloon devices.
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The overall recommendation is grade C for use of BCD for paranasal sinus inflammatory disease, but well-controlled randomized trials are needed.
Background on chronic rhinosinusitis
Chronic rhinosinusitis (CRS) represents a clinical disorder characterized by inflammation of the mucosa of the nose and paranasal sinuses of 12 weeks’ duration. A European Position Paper on Rhinosinusitis and Nasal Polyposis clinically defines CRS by 2 or more symptoms, 1 of which is nasal blockage/obstruction/congestion or nasal discharge with or without facial pain/pressure and/or reduction or loss of smell. Symptomatology is supported by endoscopic evidence of mucopurulence, edema, or polyps, and/or computed tomography (CT), presence of mucosal thickening, or air-fluid levels in the sinuses. CRS is one of the most common chronic medical conditions in the United States, afflicting approximately 31 million Americans. The illness accounts for 18 million to 22 million office visits annually, resulting in an estimated $6 billion in direct and indirect health care expenditures. CRS not only causes physical symptoms but also results in significant functional and emotional impairment, with quality of life scores similar to those of patients with other chronic debilitating illnesses, including congestive heart failure, angina, and back pain. The pathophysiologic mechanisms resulting in CRS remain elusive. A variety of host and environmental factors have been implicated, including derangements in innate and adaptive immunity, ciliary dysfunction, inhalant allergies, infectious agents (viral, bacterial, and/or fungal), superantigens, biofilms, and osteitis.
Medical therapy remains the cornerstone in the overall management schema of patients with CRS. This therapy typically entails various oral and topical agents, such as antibiotics, steroids, antihistamines, leukotriene receptor antagonists, saline irrigations, and mucolytics.
Functional endoscopic sinus surgery (FESS) represents the main surgical strategy for management of medically recalcitrant CRS. FESS is a minimally invasive, mucosal-sparing surgical technique that is designed to achieve 1 or more of the following goals:
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Open the sinuses to facilitate ventilation and drainage
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Remove polyps and/or osteitic bone fragments to reduce the inflammatory load
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Enlarge the sinus ostia to achieve optimal instillation of topical therapies
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Obtain bacterial and fungal cultures and tissue for histopathology
FESS has been shown to be effective in improving symptoms and quality of life (QOL) in adult patients with CRS. A recent multi-institutional prospective trial showed improvement in QOL in both medically and surgically treated patients with CRS; however, the FESS group experienced significantly more improvement in disease-specific QOL, reduction in need for systemic antibiotics and steroids, and decrease in missed work/school days.
Overview of balloon catheter technologies
Balloon Sinuplasty TM
The use of balloon catheters for frontal sinus dilation was initially described by Lanza in 1993. He used Fogarty balloon catheters under endoscopic guidance in post-FESS patients to achieve temporary ventilation and drainage of the frontal recess. In 2002, California-based engineers started the process of adapting cardiac catheters to perform paranasal sinus balloon dilation. Balloon catheter technology cleared the US Food and Drug Administration (FDA) 510(k) pathway in April 2005, being launched as balloon sinuplasty (Acclarent, Inc., Menlo Park, CA). In contrast with traditional balloons that are compliant and conform to regional anatomy, the new device is semirigid and noncompliant, with the ability to displace adjacent bone and tissue on inflation. The basic premise of balloon catheter dilation (BCD) is the Seldinger technique, with initial access being gained by endoscopic placement of a guide catheter. A flexible guide is introduced through the guide catheter and its position in the targeted sinus confirmed by fluoroscopy, transillumination, or image guidance. The balloon catheter is then advanced over the guidewire and gradually inflated to dilate the obstructed sinus ostium.
The initial cadaver study on BCD was presented at the annual American Rhinologic Society meeting in 2005. Technical feasibility and safety were evaluated by dilation of 31 sinus ostia (9 maxillary, 11 sphenoid, 11 frontal) in 6 cadaver heads. BCD successfully dilated all 31 sinuses and did not result in adjacent skull base or orbital injury in any cases. The investigators posited that balloon technology also seemed to impart less mucosal trauma than standard endoscopic instruments, although no comparative analysis was performed in the study. This work was followed by the first patient trial on BCD in 10 patients with persistent CRS after failed medical therapy. A total of 18 sinuses were dilated, with 8 of 10 patients undergoing concurrent ethmoidectomy. All sinuses were successfully dilated without adverse events, though the investigators noted that the maxillary sinus was the most difficult to cannulate given the position of the natural ostium relative to the uncinate process. This study served as proof of concept in a limited number of patients without any follow-up period. The impact on the underlying disease process was unclear.
LacriCATH
The LacriCATH system (Quest Medical, Inc., Allen, TX) is an established balloon device used for dilation of the lacrimal outflow system for chronic epiphora. Citardi and Kanowitz performed endoscopic paranasal sinus dissection in 3 cadaver heads using conventional FESS instrumentation concurrently with the lacrimal balloon for BCD. Frontal recess dissection was successfully performed in all 6 sinuses with FESS instruments and BCD, and all 6 sphenoid sinuses were also successfully dilated. It was not feasible to reliably pass the balloon through the maxillary natural ostium, with only 3 of 6 being successfully dilated with this technique. This study provided proof of concept in a cadaver model, precluding extrapolation of the intervention in patients with CRS. The study highlighted the potential technical limitation of BCD of the maxillary sinus in patients with an intact uncinate process.
FinESS
FinESS (Functional Infundibular Endoscopic Sinus System [Entellus Medical, Inc., Maple Grove, MN]) obtained FDA clearance in April 2008 and was launched at the annual American Academy of Otolaryngology meeting later that year. The transantral dilation system uses a flexible 0.5-mm endoscope and dual-channel cannula to localize the maxillary sinus ostia via the canine fossa approach. BCD of the maxillary ostium and ethmoid infundibulum is then performed under endoscopic visualization. The initial data on this device were reported in a multicenter study (Balloon Remodeling Antrostomy Therapy [BREATHE] I) assessing outcomes and safety in patients with CRS. Fifty-five of 58 (94.8%) maxillary ostia were successfully treated, with 97% being performed under local anesthesia with or without minimal sedation. Mean Sinonasal Outcome Test (SNOT-20) scores had statistically improved at 6 months, with patency in 95.8% by CT imaging. Follow-up data showed sustained improvement in all 4 domains on SNOT-20 at 1 year. These 2 studies provide a proof of clinical concept of this technology. The technology may be applicable to patients with limited disease focused at the maxillary infundibulum; however, broader application to the larger subset of CRS is not afforded by the data.
Overview of balloon catheter technologies
Balloon Sinuplasty TM
The use of balloon catheters for frontal sinus dilation was initially described by Lanza in 1993. He used Fogarty balloon catheters under endoscopic guidance in post-FESS patients to achieve temporary ventilation and drainage of the frontal recess. In 2002, California-based engineers started the process of adapting cardiac catheters to perform paranasal sinus balloon dilation. Balloon catheter technology cleared the US Food and Drug Administration (FDA) 510(k) pathway in April 2005, being launched as balloon sinuplasty (Acclarent, Inc., Menlo Park, CA). In contrast with traditional balloons that are compliant and conform to regional anatomy, the new device is semirigid and noncompliant, with the ability to displace adjacent bone and tissue on inflation. The basic premise of balloon catheter dilation (BCD) is the Seldinger technique, with initial access being gained by endoscopic placement of a guide catheter. A flexible guide is introduced through the guide catheter and its position in the targeted sinus confirmed by fluoroscopy, transillumination, or image guidance. The balloon catheter is then advanced over the guidewire and gradually inflated to dilate the obstructed sinus ostium.
The initial cadaver study on BCD was presented at the annual American Rhinologic Society meeting in 2005. Technical feasibility and safety were evaluated by dilation of 31 sinus ostia (9 maxillary, 11 sphenoid, 11 frontal) in 6 cadaver heads. BCD successfully dilated all 31 sinuses and did not result in adjacent skull base or orbital injury in any cases. The investigators posited that balloon technology also seemed to impart less mucosal trauma than standard endoscopic instruments, although no comparative analysis was performed in the study. This work was followed by the first patient trial on BCD in 10 patients with persistent CRS after failed medical therapy. A total of 18 sinuses were dilated, with 8 of 10 patients undergoing concurrent ethmoidectomy. All sinuses were successfully dilated without adverse events, though the investigators noted that the maxillary sinus was the most difficult to cannulate given the position of the natural ostium relative to the uncinate process. This study served as proof of concept in a limited number of patients without any follow-up period. The impact on the underlying disease process was unclear.
LacriCATH
The LacriCATH system (Quest Medical, Inc., Allen, TX) is an established balloon device used for dilation of the lacrimal outflow system for chronic epiphora. Citardi and Kanowitz performed endoscopic paranasal sinus dissection in 3 cadaver heads using conventional FESS instrumentation concurrently with the lacrimal balloon for BCD. Frontal recess dissection was successfully performed in all 6 sinuses with FESS instruments and BCD, and all 6 sphenoid sinuses were also successfully dilated. It was not feasible to reliably pass the balloon through the maxillary natural ostium, with only 3 of 6 being successfully dilated with this technique. This study provided proof of concept in a cadaver model, precluding extrapolation of the intervention in patients with CRS. The study highlighted the potential technical limitation of BCD of the maxillary sinus in patients with an intact uncinate process.
FinESS
FinESS (Functional Infundibular Endoscopic Sinus System [Entellus Medical, Inc., Maple Grove, MN]) obtained FDA clearance in April 2008 and was launched at the annual American Academy of Otolaryngology meeting later that year. The transantral dilation system uses a flexible 0.5-mm endoscope and dual-channel cannula to localize the maxillary sinus ostia via the canine fossa approach. BCD of the maxillary ostium and ethmoid infundibulum is then performed under endoscopic visualization. The initial data on this device were reported in a multicenter study (Balloon Remodeling Antrostomy Therapy [BREATHE] I) assessing outcomes and safety in patients with CRS. Fifty-five of 58 (94.8%) maxillary ostia were successfully treated, with 97% being performed under local anesthesia with or without minimal sedation. Mean Sinonasal Outcome Test (SNOT-20) scores had statistically improved at 6 months, with patency in 95.8% by CT imaging. Follow-up data showed sustained improvement in all 4 domains on SNOT-20 at 1 year. These 2 studies provide a proof of clinical concept of this technology. The technology may be applicable to patients with limited disease focused at the maxillary infundibulum; however, broader application to the larger subset of CRS is not afforded by the data.
Evidence-based clinical assessment
Given the paucity of controlled studies with a comparator group, the role of the various balloon catheter devices in the management of CRS and its subtypes remains to be elucidated. Thus, definitive recommendations on how to evaluate patients thought suitable for BCD are not possible. Nonetheless, the available database shows multitude of potential applications in patients with paranasal sinus inflammatory disease. Studies have reported on both adult and pediatric CRS refractory to maximal medical therapy. Patients with limited sinus disease have also been evaluated. Several studies have explored the usefulness of BCD in frontal sinus disease. Studies have also evaluated the use of BCD in the office and intensive care unit (ICU) settings. The evidence base available for the various applications is evaluated later.
Evidence-based surgical technique
Adult Medically Refractory CRS
Multiple retrospective case series have reported on the usefulness of BCD on medically refractory adult CRS. The present analysis focuses on the salient studies to highlight the current state of the evidence.
CLEAR study
The initial large-scale investigation, dubbed the Clinical Evaluation to Confirm Safety and Efficacy of Sinuplasty in the Paranasal Sinuses (CLEAR) study, reported on 109 patients with nonpolypoid CRS unresponsive to medical management undergoing planned FESS. Follow-up evaluations were performed at 1, 2, 12, and 24 weeks, with main outcome measures being ostial patency, SNOT-20 scores, and global rating of improvement. Overall, 52% of patients underwent concomitant ethmoidectomy, or so-called hybrid procedures. The mean Lund-Mackay scores for the balloon-only and hybrid groups were 6.1 and 10.4, respectively.
Most procedures were performed uneventfully without any cases of cerebrospinal fluid (CSF) leaks, orbital injury, or epistaxis requiring packing. BCD seemed to be technically feasible, although there were 12 device malfunctions. Endoscopic sinus ostial patency rates at 24 weeks were 91% for maxillary sinus, 82% at frontal sinus, and 60% for sphenoid sinus. A significant number of frontal (17%) and sphenoid (39%) sinuses were not evaluable because of inadequate postoperative endoscopic visualization. A statistically significant decrease in SNOT-20 scores was noted for both the balloon and hybrid groups: scores for the patients who had balloons decreased from 2.14 to 1.27, whereas the hybrid scores improved from 2.42 to 1.02.
One-year follow-up data were reported on 66 patients from the original cohort. The remainder was excluded from the analysis because of attrition, loss to follow-up, and loss of study sites. Postoperative ostial patency by endoscopy and CT was 93.5% for maxillary sinus, 91.9% for frontal sinus, and 86.1% for sphenoid sinus. Mean SNOT-20 scores for balloon-only and hybrid subsets improved to 0.95 and 0.87, respectively. Additional 2-year follow-up data were published on 65 of the patients. The SNOT-20 scores for the balloon-only and hybrid groups decreased to 1.09 and 0.66, respectively. The Lund-Mackay scores improved from 5.7 to 1.8 and from 12.1 to 3.3 for balloon-only and hybrid patients, respectively. Overall, 85% of patients reported symptom improvement, with 15% remaining the same and 0% worse.
Many important observations can be gleaned from the CLEAR series. It attests to the technical feasibility and safety of the balloon to achieve sinus ostia dilatation. Further, 1-year and 2-year follow-up studies showed the potential for reasonable ostial patency over this time period. However, many questions remain unanswered. The patient cohort for these studies was not clearly defined; moreover, a uniform management algorithm was not applied to tailor the medical and surgical therapy. Thus, it is unclear whether the data can be generalized to all patients with CRS.
The CLEAR study serves as a representative example of a single-arm, uncontrolled, observational study that has been historically accepted in rhinology to justify surgical interventions, including FESS. However, the lack of a comparison group limits meaningful interpretation of the results; it precludes any efficacy claims relative to FESS. Comparison of the mean SNOT-20 scores for the balloon-only and hybrid groups offers some insights. The balloon-only group improved from a baseline of 2.14 to 0.99 and 1.09 at 1 year and 2 years, respectively. In contrast, the hybrid group started at higher mean SNOT-20 score of 2.42, improving to 0.68 and 0.64 at 1 year and 2 years, respectively. This finding suggests that patients undergoing concurrent ethmoidectomy not only have higher baseline SNOT-20 scores but also derive greater benefit from surgery. Although the data were intended to be interpreted in this manner, they highlight the potential usefulness of direct comparative trials to better understand the role of BCD compared with FESS.
BCD outcomes: retrospective study from a multicenter registry
In the largest retrospective study to date, Levine and colleagues reported outcomes of BCD on 1036 patients from a multicenter registry. BCD was used in 3276 sinuses, with a mean of 3.2 sinuses per patient. Sinonasal symptoms improved in 95.2%, were unchanged in 3.8%, and were worse in 1.0% of patients. Postoperative infections were significantly less frequent and less severe compared to before surgery. No major adverse events were attributable to balloons, although 2 CSF leaks were documented in patients undergoing concurrent ethmoidectomy. Six cases had minor bleeding requiring packing or cautery. Perhaps the most important observation that stems from the data is the safety profile of BCD. However, the study does make it possible to reliably assess the impact of BCD on CRS. The data are pooled across 27 sites with no standardization of medical treatment or indications for surgery. The starting burden of disease was not defined by endoscopy and/or CT. The use of subjective symptom improvement as the primary endpoint and lack of validated outcome measures prevents robust assessment of BCD on the underlying disease process.
BCD versus FESS: comparative retrospective analysis
Friedman and colleagues performed a comparative retrospective analysis of prospectively collected data in 70 patients undergoing BCD versus FESS. Inclusion criteria included recurrent rhinosinusitis in patients with either a persistently abnormal CT after 4 weeks of continuous therapy or an abnormal CT during treatment, with posttreatment normalization and 3 or more recurrences per year. Exclusion criteria included Lund-McKay scores greater than 12, significant polyposis, osteoneogenesis, or systemic disease. Thirty-five patients in each treatment arm were assessed by SNOT-20 scores, global patient assessment, postoperative narcotic usage, and cost at a minimum of 3 months follow-up. The SNOT-20 scores improved from 2.8 to 0.78 for the balloon group and 2.7 to 1.29 from the FESS group, showing clinically and statistically significant improvement in both groups. Patient satisfaction was higher and narcotic usage was lower in the BCD group. The average cost of BCD ($12,657) was less than that of FESS ($14,471); the lower charges were attributed to shorter operative and recovery times and reduced need for general anesthesia with BCD.
The results may suggest the superiority of BCD compared with FESS in this comparative study. However, closer analysis of the data shows that the study represents a highly selectively patient sample that did not undergo matching or randomization. The patients decided on their surgical intervention, thus likely influencing the symptom and satisfaction scores. Furthermore, the study did not report on ostial patency for this patient group, acknowledging the inherent limitations in adequate endoscopic visualization in patients with an intact uncinate process. The short follow-up period in a chronic inflammatory process that often spans years is an additional drawback that precludes meaningful interpretation of the data. In addition, the operative charges are an estimation at best.
Pediatric Medically Refractory CRS
BCD for medically recalcitrant CRS
Ramadan reported initial data on technical feasibility and safety of BCD in children. Thirty children with medically recalcitrant CRS underwent BCD; concurrent adenoidectomy was performed in 13 patients (43%). The procedures were technical feasible in 51 of 56 sinuses (91%) with no complications attributable to BCD. The feasibility rate was 98% in normal sinuses, decreasing to 60% in hypoplastic sinuses. The average fluoroscopy time was 18 seconds per sinus; mean fluoroscopy exposure was 0.18 mGy. The preliminary data again attest to the safety of BCD. They suggest that, although technically feasible in children, the inherent limitations posed by the smaller, especially hypoplastic, sinuses result in a lower cannulation rate in children. The study provides proof of concept in pediatric patients with CRS. The short-term or long-term impact on the underlying disease process is unclear.
BCD and/or adenoidectomy for CRS
In a follow-up study, Ramadan and Terrell presented experience on 49 pediatric patients with CRS undergoing BCD and/or adenoidectomy with postoperative follow-up of 1 year. The groups were matched except for age, with the adenoidectomy-alone group being statistically younger (4.8 years) than the balloon group (7.7 years). The comparative groups included adenoidectomy alone or BCD ; 17 in the latter group also underwent adenoidectomy. Symptom improvement, defined as a decrease of 0.5 or more on Sinonasal-5 (SN-5) questionnaire, was seen in 24 (80%) and 10 (52.6%) in the balloon-alone and adenoidectomy-alone groups, respectively. These data suggest the potential usefulness of BCD in pediatric patients. However, similarly to the study by Friedman and colleagues, the 2 groups represent highly selective samples without any attempt at randomization. Given that 17 of the 30 in the balloon group underwent concomitant adenoidectomy, the impact of BCD on the underlying disease process and SN-5 scores is unclear. The intervention of adenoidectomy in both groups confounds the ability to interpret the findings.
BCD in children with CRS: prospective, multicenter, nonrandomized study
A subsequent prospective, multicenter, nonrandomized study evaluated the efficacy of BCD in 32 children with CRS. Concurrent adenoidectomy was performed in 15 patients. Twenty-four patients (75%) completed the 52 weeks follow-up. BCD was successful in 56 of 63 (89%) sinuses. Of the 7 failed sinuses, 3 were hypoplastic maxillary sinuses, 3 were sphenoid sinuses, and 1 was a frontal sinus. The SN-5 score improved from 4.9 at baseline to 2.95 at 52 weeks. Overall, improvement was significant in 50%, moderate in 29%, and mild in 8%. One had no improvement, whereas 2 worsened in the postoperative period. Although this study makes a compelling case for BCD in pediatric patients, the impact of BCD is difficult to discern, given that 15 (46.9%) had simultaneous adenoidectomy and 6 (18.9%) had concurrent ethmoidectomy. The potential beneficial effect of adenoidectomy in pediatric patients with CRS cannot be understated. The adenoid may serve as a reservoir of potentially pathogenic bacteria; the overall adenoid bacterial isolation rate has been noted to be as high as 79%, with isolate rate increasing with sinusitis grade. A recent meta-analysis of adenoidectomy in medically refractory CRS showed improvement of sinusitis symptoms or outcomes in 69.3% of the patients. Given its simplicity, effectiveness, and low-risk profile, adenoidectomy likely represents a first-line therapy for uncomplicated pediatric CRS. Direct comparative trials of adenoidectomy, BCD, and FESS are required to better understand the role of balloons in the management algorithm of pediatric CRS.
Limited Disease
Two studies using the FinESS system have explored the usefulness of BCD for limited disease focused in the maxillary sinus with or without involvement of the ethmoid infundibulum. As mentioned earlier, the data has shown technical feasibility in 94.8%, with improvement in SNOT-20 scores at 6 months and 1 year. These data have provided proof of concept for the new device, suggesting potential usefulness in patients with limited disease. However, careful evaluation of the BREATHE I 6-month data shows that they mirror many of the deficiencies evident in the CLEAR study. The patient population for the study group in not clearly defined. CT imaging, showing an air-fluid level or maxillary ostial or infundibular narrowing with greater than or equal to 2-mm maxillary mucosal thickening served as the inclusionary criteria; however, the degree of maxillary opacification or level of infundibular narrowing were not objectively characterized beyond the point of inclusion. The medical therapy was inconsistently applied across the patient group. Furthermore, given that 2 simultaneous interventions (transantral approach, maxillary ostia BCD) were used, the impact of each is difficult to discern from the study design. Nonetheless, the data suggest that this may be a potential option for limited disease, especially in the office setting, and deserves additional investigation.
Frontal Sinus Disease
BCD has been proposed as a potential minimally invasive alternative to endoscopic frontal sinusotomy (EFS) for frontal sinus disease. Several studies have evaluated the usefulness of balloons in this regard ( Table 1 ). Khalid and colleagues performed frontal recess BCD in 8 cadaver heads to evaluate the patterns of fracture of bony lamellae and change in frontal recess dimensions using preintervention and postintervention endoscopy and CT. This, in turn, was compared with the degree of change seen with EFS. BCD resulted in statistically less change in mean coronal (0.9 mm vs 2.6 mm) and sagittal (1.0 mm vs 4.0 mm) dimensions compared with EFS. The most commonly fractured lamella after BCD was the anterior face of the ethmoid bulla (56%). The clinical significance of these 2 interventions on frontal sinus disease is not evident from the cadaveric data; from a technical perspective, it suggests that BCD results in smaller frontal sinus outflow tract dimensions and may not produce consistent fracture patterns of the bony lamellae of the frontal recess cells.
