Post-operative complications after removal of sporadic vestibular schwannoma via retrosigmoid-suboccipital approach: current diagnosis and management

Retrolabyrinthine approach to the lateral skull base: The value of preoperative temporal bone CT analysis

PURPOSE

The most used neurosurgical approach to reach cerebellar-pontine angle is the retrosigmoid route. This article describes the presigmoid approach which requires excellent knowledge of the labyrinthine block together with quantitative analysis of temporal bone CT.

METHODS

CT-based quantitative measurements were obtained in patients undergoing vestibular neurectomy with a presigmoid approach. Eighteen patients were enrolled, and five measures were taken: Trautmann's area, the petro-clival angle, presigmoid dura length and its angle. The relationship between these measurements and hospitalization days, operating times, and complications was explored.

RESULTS

The posterior semicircilar canal (PSC)-sigmoid sinus (SS) distance, presigmoid dura- internal auditory canal (IAC)-PSC angle, and duration of surgery are predictors of complications. Specifically, a PSC-sigmoid sinus distance <11 mm, a dura presig-IAC-PSC angle <14 are associated with the highest risk of complications.

CONCLUSION

Preoperative temporal bone CT scan can guide the surgeon through the narrowest areas of the surgical approach. Trautmann's triangle area and petro-clival angle reduction are challenging and can be faced with combined microscopic-endoscopic technique, and with optics angulation-rotation. The retrolabyrinthine approach can enable hearing preservation and minimal cerebellar retraction.

Cerebrovascular Complications of Vestibular Schwannoma Surgery

Objective Cerebrovascular complications (CVC) are rare consequences of vestibular schwannoma (VS) surgery. Our objective was to assess incidences of findings suggestive of postoperative CVC in a large single surgeon cohort, as well as potential risk factors, and implications.

Study Design A cohort of 591 patients was retrospectively reviewed. Postoperative magnetic resonance images were screened for findings suggestive of stroke, T2 hyperintensity in the cerebellopontine angle structures or new encephalomalacia. Clinical records were queried for findings consistent with postoperative CVC.

Results In total, 61 patients had radiographic findings consistent with possible postoperative CVC (10%); of them, eight had documented intraoperative vascular injury (1.4%), and four had postoperative clinical exam changes indicative of CVC (0.7%). Clinically manifest intraoperative vascular injuries occurred in four patients and involved the petrosal venous complex (n = 3, 5%) or anterior inferior cerebellar artery (n = 1, 2%); clinical deficits included hemiparesis (n = 1, 2%), facial anesthesia (n = 2, 4%), dysphagia (n = 2, 2%), and unfavorable facial nerve function in two (50%). Three out of four patients in this group required out-of-home placement (75%). Clinical CVCs (n = 4) were not significantly associated with tumor size, tumor cyst, gross total resection, or length of stay. Patients with clinical CVC were significantly more likely to require posthospitalization rehabilitation (19 vs. 75%, p = 0.02; 14 vs. 100%, p = 0.0002).

Conclusion Although radiographic findings suggestive of CVC were unexpectedly common in this cohort, intraoperative vascular injury and postoperative clinical CVC were exceedingly rare. The association between unfavorable facial nerve outcome and clinical CVC is likely a marker for more difficult operations, predisposing to higher risk of complications.

Morbidity Rate of the Retrosigmoid versus Translabyrinthine Approach for Vestibular Schwannoma Resection

Background and Objectives

Controversy related to the choice of surgical approach for vestibular schwannoma (VS) resection remains. Whether the retrosigmoid (RS) or translabyrinthine (TL) approach should be performed is a matter of debate. In the context of a lack of clear evidence favoring one approach, we conducted a retrospective study to compare the morbidity rate of both surgical approaches.

Subjects and Methods

168 patients underwent surgical treatment (2007-2013) for VS at our tertiary care center. There were no exclusion criteria. Patients were separated into two groups according to the surgical approach: TL group and RS group. Signs and symptoms including ataxia, headache, tinnitus, vertigo and cranial nerve injuries were recorded pre- and postoperatively. Surgical complications were analyzed. Perioperative facial nerve function was measured according to House-Brackmann grading system.

Results

Tumor resection was similar in both groups. Facial paresis was significantly greater in RS group patients preoperatively, in the immediate postoperative period and at one year follow-up (p<0.05). A constant difference was found between both groups at all three periods (p=0.016). The evolution of proportion was not found to be different between both groups (p=0.942), revealing a similar rate of surgically related facial paresis. Higher rate of ataxic gait (p=0.019), tinnitus (p=0.039) and cranial nerve injuries (p=0.016) was found in RS group patients. The incidence of headache, vertigo, vascular complications, cerebrospinal fluid leak and meningitis was similar in both groups. No reported mortality in this series.

Conclusions

Both approaches seem similar in terms of resection efficacy. However, according to our analysis, the TL approach is less morbid. Thus, for VS in which hearing preservation is not considered, TL approach is preferable.

Creating a stem cell niche in the inner ear using self-assembling peptide amphiphiles

The use of human embryonic stem cells (hESCs) for regeneration of the spiral ganglion will require techniques for promoting otic neuronal progenitor (ONP) differentiation, anchoring of cells to anatomically appropriate and specific niches, and long-term cell survival after transplantation. In this study, we used self-assembling peptide amphiphile (PA) molecules that display an IKVAV epitope (IKVAV-PA) to create a niche for hESC-derived ONPs that supported neuronal differentiation and survival both in vitro and in vivo after transplantation into rodent inner ears. A feature of the IKVAV-PA gel is its ability to form organized nanofibers that promote directed neurite growth. Culture of hESC-derived ONPs in IKVAV-PA gels did not alter cell proliferation or viability. However, the presence of IKVAV-PA gels increased the number of cells expressing the neuronal marker beta-III tubulin and improved neurite extension. The self-assembly properties of the IKVAV-PA gel allowed it to be injected as a liquid into the inner ear to create a biophysical niche for transplanted cells after gelation in vivo. Injection of ONPs combined with IKVAV-PA into the modiolus of X-SCID rats increased survival and localization of the cells around the injection site compared to controls. Human cadaveric temporal bone studies demonstrated the technical feasibility of a transmastoid surgical approach for clinical intracochlear injection of the IKVAV-PA/ONP combination. Combining stem cell transplantation with injection of self-assembling PA gels to create a supportive niche may improve clinical approaches to spiral ganglion regeneration.

Pediatric Auditory Brainstem Implant Surgery

Auditory brainstem implants (ABIs) provide auditory perception in patients with profound hearing loss who are not candidates for the cochlear implant (CI) because of anatomic constraints or failed CI surgery. Herein, the authors discuss (1) preoperative evaluation of pediatric ABI candidates, (2) surgical approaches, and (3) contemporary ABI devices and their use in the pediatric population. The authors also review the surgical and audiologic outcomes following pediatric ABI surgery. The authors' institutional experience and the nearly 200 cases performed in Europe and the United States indicate that ABI surgery in children can be safe and effective.

Anatomical Factors Influencing Selective Vestibular Neurectomy: A Comparison of Posterior Fossa Approaches

Objectives To identify measurable anatomical factors that may guide the surgical approach for posterior fossa selective vestibular neurectomy (SVN) and predict identification of the vestibulocochlear cleavage (VCC) plane. Study Design Dissection of fixed cadaveric heads through retrolabyrinthine and retrosigmoid-internal auditory canal (RSG-IAC) approaches with measurement of landmarks. Setting Cadaveric dissection model. Main Outcome Measures Area of the Trautmann triangle (TT) and the distance from the posterior semicircular canal to the anterior border of the sigmoid along the posterior Donaldson line (pDL). VCC planes from each approach were calculated and compared. Results Overall mean pDL was 8.53 mm (range: 5-11.5 mm); mean TT area was 124 mm(2) (range: 95-237 mm(2)). The VCC was identified in 63% of ears through the retrolabyrinthine (RVN) approach alone, whereas 37% of ears required the RSG-IAC approach. In ears requiring IAC dissection, the VCC was found within 1 to 2 mm distal to the porus. The pDL (p < 0.05) and area of TT (p < 0.05) were significantly larger in the RVN group compared with the RSG-IAC group. Conclusion Ears amenable to the RVN approach had a greater pDL and TT area. These anatomical measurements may have a role in surgical planning and the choice of approach for SVN.

Long-term quality of life in patients with vestibular schwannoma: an international multicenter cross-sectional study comparing microsurgery, stereotactic radiosurgery, observation, and nontumor controls

OBJECT

The optimal treatment for sporadic vestibular schwannoma (VS) is highly controversial. To date, the majority of studies comparing treatment modalities have focused on a narrow scope of technical outcomes including facial function, hearing status, and tumor control. Very few publications have investigated health-related quality of life (HRQOL) differences between individual treatment groups, and none have used a disease-specific HRQOL instrument.

METHODS

All patients with sporadic small- to medium-sized VSs who underwent primary microsurgery, stereotactic radiosurgery (SRS), or observation between 1998 and 2008 were identified. Subjects were surveyed via postal questionnaire using the 36-Item Short Form Health Survey (SF-36), the 10-item Patient-Reported Outcomes Measurement Information System short form (PROMIS-10), the Glasgow Benefit Inventory (GBI), and the Penn Acoustic Neuroma Quality-of-Life (PANQOL) scale. Additionally, a pool of general population adults was surveyed, providing a nontumor control group for comparison.

RESULTS

A total of 642 respondents were analyzed. The overall response rate for patients with VS was 79%, and the mean time interval between treatment and survey was 7.7 years. Using multivariate regression, there were no statistically significant differences between management groups with respect to the PROMIS-10 physical or mental health dimensions, the SF-36 Physical or Mental Component Summary scores, or the PANQOL general, anxiety, hearing, or energy subdomains. Patients who underwent SRS or observation reported a better total PANQOL score and higher PANQOL facial, balance, and pain subdomain scores than the microsurgical cohort (p < 0.02). The differences in scores between the nontumor control group and patients with VS were greater than differences observed between individual treatment groups for the majority of measures.

CONCLUSIONS

The differences in HRQOL outcomes following SRS, observation, and microsurgery for VS are small. Notably, the diagnosis of VS rather than treatment strategy most significantly impacts quality of life. Understanding that a large number of VSs do not grow following discovery, and that intervention does not confer a long-term HRQOL advantage, small- and medium-sized VS should be initially observed, while intervention should be reserved for patients with unequivocal tumor growth or intractable symptoms that are amenable to treatment. Future studies assessing HRQOL in VS patients should prioritize use of validated disease-specific measures, such as the PANQOL, given the significant limitations of generic instruments in distinguishing between treatment groups and tumor versus nontumor subjects.

Subtotal petrosectomy and cerebrospinal fluid leakage in unilateral anacusis

Objective This study presents a group of patients experiencing recurrent cerebrospinal fluid (CSF) leakage associated with ipsilateral anacusis who underwent subtotal petrosectomies with the goal of stopping the CSF leak and preventing meningitis. Materials and Methods Eight patients with CSF leakage were enrolled: three patients with giant vestibular schwannomas had CSF leakage after gamma knife failure and subsequent removal via a retrosigmoid approach; two patients had malformations at the level of the inner ear with consequent translabyrinthine fistulas; two had posttraumatic CSF leakages; and one had a CSF leakage coexisting with an encephalocele. Two patients developed meningitis that resolved with antibiotic therapy. Each patient had preoperative anacusis and vestibular nerve areflexia on the affected side. Results The patients with congenital or posttraumatic CSF leaks had undergone at least one unsuccessful endaural approach to treat the fistula. All eight patients were treated successfully with a subtotal petrosectomy. The symptoms disappeared within 2 months postoperatively. No meningitis, signs of fistula, or other symptoms occurred during the follow-up. Conclusion A subtotal petrosectomy should be the first choice of treatment in patients with recurrent CSF leakage whenever there is associated unilateral anacusis.

Reconstruction after retrosigmoid approaches using autologous fat graft-assisted Medpor Titan cranioplasty: assessment of postoperative cerebrospinal fluid leaks and headaches in 60 cases

BACKGROUND

Postoperative cerebrospinal fluid (CSF) leaks and headaches remain potential complications after retrosigmoid approaches for lesions in the posterior fossa and cerebellopontine angle. The authors describe a simple repair technique with an autologous fat graft-assisted Medpor Titan cranioplasty and investigate the incidence of postoperative CSF leaks and headaches using this technique.

METHODS

A retrospective chart review was conducted on all cases (n = 60) of retrosigmoid craniectomy from September 2009 to May 2014 in patients who underwent fat graft-assisted cranioplasty. After obtaining a watertight dural closure and sealing off any visible mastoid air cells with bone wax, an autologous fat graft was placed over the dural suture line and up against the waxed-off air cells. The fat graft filled the retrosigmoid cranial defect and was then bolstered with a Medpor Titan (titanium mesh embedded in porous polyethylene) cranioplasty. A postoperative mastoid pressure dressing was applied for 48 h, and prophylactic lumbar drainage was not used. Factors examined in this study included postoperative CSF leak (incisional, rhinorrhea, otorrhea), pseudomeningocele formation, incidence and severity of postoperative headache, length of hospital stay, and length of follow-up.

RESULTS

No patients developed postoperative CSF leaks (0 %), pseudomeningoceles (0 %), or new-onset postoperative headaches (0 %) with the described repair technique. There were no cases of graft site morbidity such as hematoma or wound infection. Mean duration of postoperative hospital stay was 3.8 days (range 2-10 days). Mean postoperative follow-up was 12.4 months (range 2.0-41.1 months).

CONCLUSIONS

Our multilayer repair technique with a fat graft-assisted Medpor Titan cranioplasty appears effective in preventing postoperative CSF leaks and new-onset postoperative headaches after retrosigmoid approaches. Postoperative lumbar drainage may not be necessary.

Transmastoid retrosigmoid approach to the cerebellopontine angle: surgical technique

BACKGROUND

The traditional suboccipital craniotomy in the retrosigmoid approach gives limited exposure to the cerebellopontine angle (CPA) structures and necessitates cerebellar retraction, whereas the addition of drilling of the mastoid process with reflection of venous sinuses offers wider exposure of the CPA and avoids cerebellar retraction. We describe the details of the surgical technique and provide radiological measurements substantiating the advantages of this approach.

OBJECTIVE

To validate the usefulness of partial mastoidectomy in the retrosigmoid approach and to evaluate the complications of this maneuver.

METHODS

Radiological CPA measurements on computed tomography bone window films were made on the last consecutive 20 patients who underwent CPA surgery via the transmastoid retrosigmoid approach. We measured the distance and angle of work by this approach and compared the measurements with those using the traditional retrosigmoid approach if that would have been used in each case. We also reviewed 432 patients from the records of the senior author to evaluate possible complications of this approach.

RESULTS

The mean working distance for the transmastoid approach was 23.06 mm, whereas the working distance in the traditional approach was 46.44 mm. The mean increase in the angle of work after drilling of the mastoid was 25.39 degrees, and the simple average of increased distance in lateral exposure was 26.66 mm.

CONCLUSION

The transmastoid retrosigmoid approach increases the exposure and gives better access to the CPA targets. This approach alleviates cerebellar retraction, facilitates surgery in the supine position, promotes the use of the endoscope, and is associated with negligible complications.

Complications of Surgery for Sporadic Vestibular Schwannoma

Objectives

We sought to investigate the postoperative complications of vestibular schwannoma excision and determine their significant clinical predictors.

Study Design

Cross-sectional.

Setting

California Hospital Inpatient Discharge Datasets 1997-2011.

Subjects and Methods

Data for vestibular schwannoma excisions performed in California were extracted using the ICD-9-CM code “04.01 excision of acoustic neuroma.” Demographics, principal payer, state of residence, comorbidities, as well as hospital case volume were examined as possible predictors. Postoperative complications and patient disposition were examined as outcome variables. Comorbidities and complications were identified using ICD-9-CM diagnoses and procedures codes.

Results

Overall, 6553 cases were examined. Comorbidities were present in 2539 (38.7%) patients. Postoperative complications occurred in 1846 (28.2%) patients; 1714 (26.2%) neurological and 337 (5.1%) medical complications. Patients’ admission ended with death or further care (ie, skilled nursing facilities) in 260 (4.0%) cases. Mortality rate was 0.2%. No significant changes were observed over time. Multivariate analysis revealed that the odds of neurological complications were greater in the 2007-2011 period (OR = 1.51; 95% CI, 1.12-2.04), in patients with comorbidities (OR = 1.48; 95% CI, 1.16-1.88), and in hospitals with low case volume (OR = 1.69; 95% CI. 1.31-2.18). The odds of medical complications were also greater in the 2007-2011 period (OR = 1.69; 95%, CI 1.02-2.80). Female gender, non-Caucasian ethnicity, presence of comorbidities, and low hospital case volume were associated with greater odds of patients requiring further care.

Conclusion

Comorbidities and low hospital case volume were major risk factors for complications. No significant changes in rates of complications from vestibular schwannoma surgery were observed over the 15-year period.

The risk of acquiring bacterial meningitis following surgery in Denmark, 1996-2009: a nationwide retrospective cohort study with emphasis on ear, nose and throat (ENT) and neurosurgery

SUMMARY

This paper estimates the risk of bacterial meningitis following surgery between 1996 and 2009 in Denmark. We conducted two retrospective nationwide cohort studies; first by linking notified bacterial meningitis cases to the National Patient Registry to see how many had undergone a surgical procedure; second, we scrutinized notified bacterial meningitis cases to see if the clinician suspected a surgical procedure to be the aetiology. We found that ear, nose and throat surgery had an 11-fold, and neurosurgery a sevenfold, increased risk compared to the reference group in the first 10 days following surgery. Streptococcus pneumoniae was the pathogen most often involved. Operation procedures involving penetration of dura mater was associated with increased risk for post-operative bacterial meningitis. In absolute numbers we found few bacterial meningitis cases after surgery; however, patients undergoing certain surgical procedures are at-risk and should be considered when national vaccination guidelines are revised.