SAFETY AND EFFICACY OF ANEURYSM TREATMENT WITH WOVEN ENDOBRIDGE: RESULTS OF THE WEBCAST
STUDY[6]
Study Question: What is the safety and efficacy of the Woven EndoBridge (WEB) device?
Despite the great overall success of endovascular therapy for treatment of both ruptured
and unruptured aneurysms, the endovascular treatment of wide-necked bifurcation aneurysms
remains challenging. The WEB device was created as a novel treatment for these aneurysms,
for which balloon- or stent-assisted coiling, and surgery remain as alternatives,
although often challenging. The WEBCAST study was a prospective, observational, multicenter,
controlled study among 10 European neurointerventional centers and represents the
first large study to assess the safety and efficacy of WEB in a prospective fashion.[6]
A similar study (French observatory) was run simultaneously in France. Pierot et al.
present the combined data from these two studies, representing the largest published
cohort of aneurysms treated with WEB.[7]
The WEB device was successfully deployed in 97% of cases though adjunct treatment
with coils or stents were required in 10% of cases. Thromboembolic events occurred
in 15% of cases with only one patient (1.8%) having clinical sequela. The aneurysms
were specifically selected by a multidisciplinary group including neurosurgeons. The
cohort was largely unruptured aneurysms (91%), with the majority of which were in
the middle cerebral artery (MCA) (52%), followed by anterior communicating artery
(18%), basilar artery terminus (18%), and internal carotid artery terminus (11%).
Treatment was determined to be efficacious at 6 months, with complete aneurysm occlusion
in 56.1% and adequate (Raymond I or II) in 85%, with relative stability of obliteration
at 1 year.
Perspective: The study was well designed and outcomes were dutifully reported. However,
the details of the aneurysms treated were unclear. Although they were all bifurcation
aneurysms with a mean neck size of 5.57 mm, it is unclear about the percentage of
patients with narrow neck aneurysms.
The basis of the WEB device is the concept of flow disruption, not dissimilar from
flow diversion. Disruption of flow by the device causes stasis and gradual thrombosis,
with the lattice at the neck allowing for eventual endothelialization to reconstruct
the parent artery. WEB, as an endosaccular device, is not thrombogenic in the way
an endoluminal stent or flow diverter is, and thus may be used without the use of
antiplatelet agents, allowing its use in patients with subarachnoid or intraventricular
hemorrhage. Despite this theoretical advantage, the authors found that any antiplatelet
use (not required per protocol) was associated with a significant lower rate of thromboembolic
events and the rate of thromboembolic events appeared to be comparable to stent-assisted
coiling (15% total, 1.8% symptomatic).[12] The cohort of aneurysms treated were largely
unruptured (87%), making the applicability of these results to ruptured aneurysms
difficult.
The authors noted the complete and adequate occlusion rates of 56% and 82%, respectively,
which is comparable to other endovascular series such as MAPS and CLARITY. Noninferiority
to these treatments falls short of the expectation of the WEB device, namely, that
it would be superior to stent- or balloon-assisted coiling. Further, several cases
(10%) required these adjuncts for satisfactory treatment, abbreviating the enthusiasm
over its standalone efficacy.
Most of the aneurysms included in this series are MCA bifurcation aneurysms, and they
would have been amenable to surgical treatment with very high obliteration rates and
low morbidity.[8] As neurosurgeons, we challenge that a complete occlusion rate of
56% for MCA bifurcation aneurysms as being ideal when compared to open microsurgery.
Summary Written by: Visish M. Srinivasan, MD and Peter Kan, MD
ENDOSCOPIC ENDONASAL CLIPPING ON INTRACRANIAL ANEURYSMS: SURGICAL TECHNIQUE AND RESULTS[4]
Study Question: Is endonasal aneurysm clipping a reasonable option for patients with
intracranial aneurysms?
The authors review a retrospectively accrued database of patients to assess the safety
and effectiveness of endonasal intracranial aneurysm clipping at a single institution
by a single treating team comprised a neurosurgeon and otolaryngologist. Presenting
signs, aneurysm size and location, ability to obtain proximal and distal vascular
control, additional procedures, occlusion rate, and postoperative complications were
analyzed. All patients obtained an intraoperative angiogram. Decision-making, technical
nuances, and challenges with the operation were also discussed.
A total of approximately 400 patients had intracranial aneurysms treated through endovascular
(about 75%) or open transcranial approaches over a 2-year period at this institution.
A total of 10 patients with 11 aneurysms underwent an endonasal approach for aneurysm
clipping during the same time span. Mean age was 50 years and 8 of the patients were
women. Seven patients presented with incidental findings and one patient each presented
with subarachnoid hemorrhage, vision loss/hypopituitarism, and an oculomotor nerve
palsy. Aneurysm size varied from 4 mm to giant, with the majority of treated aneurysms
in the 4–11 mm range. Six ophthalmic artery, three superior hypophyseal artery, one
basilar apex, and one posterior cerebral artery aneurysms were treated. Proximal and
distal control was obtained in every single case purely through the endonasal approach
except for one patient with a giant, thrombosed aneurysm that required a craniotomy
for distal control. Intraoperative angiogram demonstrated complete aneurysm occlusion
in all cases. The two patients that presented with mass effect had improvement in
their cranial nerve palsies and pituitary dysfunction. Postoperative complications
included three patients with cerebrospinal fluid (CSF) leaks, two of whom developed
meningitis. These patients were treated with additional endonasal skull base reconstruction
and antibiotics. Both patients with posterior circulation aneurysms suffered lacunar
strokes; one has recovered completely while the other has mild disability. No endocrine
dysfunction was noted.
Perspective: The discussed decisions to proceed with the endonasal corridor center
around the low occlusion/high recurrence rates and need for antiplatelet medication
with endovascular aneurysm embolization, the theoretical benefit of immediate cessation
of mass effect with aneurysm clipping, and the favorable anatomy for this surgical
approach with inferomedially-projecting paraclinoid and ventrally-projecting vertebrobasilar
aneurysms. Transcranial approaches for microsurgical clipping often require optic
nerve manipulation and neck dissections for proximal control in treating paraclinoid
aneurysms as well as significant brain retraction and a long working corridor for
low-lying basilar apex/posterior cerebral artery aneurysms. Proposed advantages of
the endonasal approach include the ability to obtain proximal control along the cavernous
segment of the internal carotid, better visualization, and a more direct approach
for certain aneurysms, minimal neurovascular retraction, and a potentially more comfortable
recovery.
Several limitations exist with the endonasal approach for aneurysm clipping. Recognized
restraints include the small working space with this corridor. With current single
shaft appliers having limited degrees of freedom and in the setting of aneurysmal
rupture or multiple clips needing to be placed for vessel reconstruction and obtaining
proximal control, the narrow channel with this approach will be a drawback. The rate
of intraoperative aneurysmal rupture in this manuscript is not stated. In addition,
the challenge of modifying endonasal skull base reconstruction techniques to accommodate
clips protruding into the sphenoid sinus may have led to the higher than usual incidence
of postoperative CSF leakage and resultant infection in this series. Furthermore,
no mention is made of the other paraclinoid and posterior circulation aneurysms treated
with endovascular embolization or transcranial clipping during this time span at this
institution. This information would be helpful to determine the preoperative selection
bias in this series.
Although controversial, the endonasal approach has been shown to be safe and effective
for limited aneurysms in several cadaveric studies and multiple other clinical case
reports and case series and should rarely be considered as an alternative for limited
patients in select high-volume centers. With higher recurrence rates and the potential
need for long-term antiplatelet therapy tempering unbridled enthusiasm with current
technical advancements in endovascular neurosurgery, transcranial clipping remains
a viable and reliable option. Basic cerebrovascular principles can be maintained through
the endonasal route for aneurysms with favorable anatomy, making this an infrequent
option that should follow a multidisciplinary vascular board review to first discuss
available transcranial and endovascular approaches. Given the very steep learning
curve with these particular cases, they should only be attempted on an individual
patient basis by neurosurgeons experienced in endoscopic endonasal and cerebrovascular
neurosurgery and otolaryngologists familiar with endoscopic skull base surgery and
reconstruction. Advancements in endoscopic vascular imaging and clip applier technology,
along with additional studies and cases, particularly those showing the effectiveness
of this approach despite intraoperative aneurysmal rupture, may enhance this approach.
Summary Written by: Anand V. Germanwala, MD
RETROSIGMOID VERSUS TRANSLABYRINTHINE APPROACH FOR ACOUSTIC NEUROMA RESECTION: AN
ASSESSMENT OF COMPLICATIONS AND PAYMENTS IN A LONGITUDINAL ADMINISTRATIVE DATABASE[3]
Study Question: Is there a difference in complications and reimbursements in the retrosigmoid
versus translabyrinthine approach for vestibular schwannoma resection?
The authors conducted a retrospective analysis of the nationwide complication and
payment rates in translabyrinthine and retrosigmoid approaches for vestibular schwannomas.
The study included 346 and 130 patients who underwent retrosigmoid and translabyrinthine
approaches, respectively, from the 2010 to 2012 MarketScan nationwide database.
The authors found no difference in patient characteristics, comorbidities, and hospitalization
characteristics between the two groups. There was a significant regional difference
in the surgical approach used. In the 30-day postoperative period, the rate of general
neurological or neurosurgical complications was similar between the two approaches.
The retrosigmoid approach had an increased rate of specific complications, including
postoperative dysrhythmia (8.4% vs. 2.3%, P = 0.022), dysphagia (10.4% vs. 3.1%, P
= 0.0089), and cranial nerve (CN) VII injury (20.2% vs. 10%, P = 0.0096). Comparing
surgeons who performed two or more acoustic neuroma procedures annually to those who
performed <2 annually, there was a decreased incidence of CN VII injury (18.7% vs.
2.6%, P = 0.0072) and postoperative dysphagia (8.9% vs. 2.6%, P = 0.24), as well as
a trend toward decreased need for repair of cerebrospinal fluid (CSF) leak (12% vs.
2.6%, P = 0.11), in the more experienced group. While the authors found no significant
difference in the incidence of lumbar drain placement (11.2% vs. 6.9%, P = 0.23) or
repair of CSF leak (11.2% vs. 11.5%, P = 0.87), fat graft use during surgical repair
of CSF leak was significantly higher in the translabyrinthine approach (19.8% vs.
60.2%, P < 0.0001). Among patients who received fat graft, the retrosigmoid approach
trended toward a greater rate of requiring CSF leak repair (15.9% vs. 6.4%, P = 0.11);
while in those without fat grafts, the need for CSF leak repair was higher in the
translabyrinthine group (10% vs. 19.2%, P = 0.093). The authors also noted that undergoing
the translabyrinthine approach and receiving a fat graft resulted in a lower rate
of CSF repair requiring surgical repair (6.4% vs. 19.2%, P = 0.047). In terms of reimbursement,
the retrosigmoid approach resulted in higher median total payments ($67,774 vs. $50,918,
P = 0.0004) and hospital payments ($50,351 vs. $36,855, P = 0.0025) than the translabyrinthine
approach. There was no difference in median physician payments or aggregate 90-day
postoperative payments between the two approaches. In addition, there was no difference
in the length of stay, follow-up, or discharge home between the two groups.
Perspective: In the current health care climate of changing reimbursement rates and
fee structure, this study provides us with the data to determine how we can both improve
patient care and decrease health care costs for patients with acoustic neuromas. As
the authors have found that the translabyrinthine approach achieves a lower rate of
postoperative facial nerve injury, dysphagia, and dysrhythmia than does the retrosigmoid
approach. Further, the total costs were lower in the translabyrinthine approach. The
differences in complication rates between the two procedures may have had an effect
on the cost differences between them. Higher volume centers and more experienced surgeons
are also able to achieve lower complication rates leading to decreased hospital stays
and decreased costs, whereas low volume centers and surgeons are more likely to utilize
the retrosigmoid approach which provides greater tumor access but is associated with
greater complication rates.[10
11] Similarly, Semaan et al. found that the retrosigmoid approach resulted in greater
hospital and Intensive Care Unit length of stay and greater adjusted total costs compared
to the translabyrinthine approach.[9] While these studies provide compelling data
for the use of the translabyrinthine approach for acoustic neuromas to decrease both
patient complications and health care costs, a prospective randomized trial is needed
to provide definitive evidence.
Summary Written by: Panayiotis Pelargos and Isaac Yang, MD
THE EFFECT OF LOCAL INTRAOPERATIVE STEROID ADMINISTRATION ON THE RATE OF POSTOPERATIVE
DYSPHAGIA FOLLOWING ANTERIOR CERVICAL DISCECTOMY AND FUSION[1]
Study Question: What is the effect of local intraoperative steroid administration
on the rate of postoperative dysphagia?
The goal of the study is to identify if local use of steroids during anterior cervical
discectomy and fusion (ACDF) has an effect on postoperative dysphagia, length of stay,
infection, or wound infection rates within 90 days of surgery. Based on current procedural
terminology (CPT) coding, the authors used a Medicare database within PearlDiver,
an insurance-based patient records database, to identify 245,745 patients undergoing
an ACDF between 2005 and 2012. Then, the “J” code was used to identify intraoperative
use of local steroid. Patients were divided into treatment (use of local steroid)
versus nontreatment (control) groups, and each was assessed for International Classification
of Diseases (ICD)-9 codes related to dysphagia and both CPT and ICD-9 codes for infection
and wound complications. Associated demographics were compared. In the short ACDF
(1–2 segments) group, 1770 patients received local steroid versus 198,230 who did
not. For long construct ACDF (3 or more segments), only 322 patient received steroids
compared to 45,432 who did not. Overall, intraoperative steroids were used more commonly
in females, patients <70 years of age, and those with a history of obesity, smoking,
and diabetes mellitus. Interestingly, dysphagia within 90 days was significantly lower
for patients receiving steroids for long ACDF (9% vs. 14.6%, odds ratio [OR] 1.7,
P = 0.005) but not short ACDF procedures (7.5% vs. 8.4%, OR 1.1, P = 0.198) when compared
to their respective controls. The length of stay was 1 day shorter for all patients
receiving local steroids (P < 0.0001), and there was no difference in rates of infection
or wound breakdown.
Perspective: Postoperative soft tissue swelling is a serious morbidity with an incidence
reported to be as high as 71% in the first 2 weeks and 12–14% at 1 year.[2] While
many studies are published regarding the factors associated with dysphagia post-ACDF,
few have looked at preventative measures. Known risk factors include female gender,
multi-level fusion, prolonged surgical duration, fusion levels of cervical 4–6, and
advanced age.[2] Studies have provided conflicting reviews on postoperative use of
intravenous steroids and only one prior study evaluated the use of triamcinolone application
to the retropharyngeal space.[5] The authors of the above article have provided an
interesting observation that using local steroids for long ACDF constructs may be
worthy of adaptation into daily practice. The study is powered by size and is likely
representative of the larger population as a whole, but the accuracy of data assessed
is of question. First, CPT codes and ICD-9 codes can both underrepresent and over
represent actual pathology as miscoding and noncoding are known errors. Second, we
are not given the details regarding the diagnosis, severity, or duration of dysphagia.
Dysphonia, another common complaint, was not included either. In addition, the database
gives no specific details about the steroids used. It is imperative to compare the
agent used, application technique, dosage, and use of postoperative drains to better
assess results and make opinions regarding personal use. Further studies investigating
the use of local steroids may help identify a protocol that can be adapted into common
practice. It may be worthwhile to assess the use of preoperative steroids both alone
and in combination with local and postoperative steroid as well.
Summary Written by: Angela Bohnen, MD
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.