CPA Tumors Research Articles

Surgical Management of CPA Tumors

Surgery of CPA tumors currently should be functional preserving and safe for the patient. The most common tumors in the area are vestibular schwannomas, followed by meningiomas and epidermoids. Despite the fact that they share common location, the treatment strategy and the operative technique in each tumor type are different. My personal philosophy for their treatment evolved over the last four decades with an experience of more than 6,000 CPA surgeries. Over the years, I have been increasingly convinced that whatever the approach is used, it should not be related by itself to any significant approach-related complications or morbidity. With the modifications of some classical approaches that we introduced, we can reach and safely remove any lesion in the area.

The Facial Nerve Palsy in Skull Base Lesions

Facial nerve paralysis may ensue after the removal of a CPA tumor or a petroclival meningioma encroaching at the level of the internal auditory canal.

Preliminary study of facial nerve F wave evaluation hypoglossal-facial nerve reconstruction with predegenerated nerve graft for peripheral facial palsy

To Preliminary study of facial nerve F wave evaluation hypoglossal-facial nerve reconstruction with pre-degenerated nerve graft for peripheral facial palsy. The clinical data were retrospectively reviewed for 30 patients with peripheral facial palsy after cerebellontine angle underwent nerve anastomosis were analyzed between November 2011 and February 2014. F wave and M wave detection were used to evaluate the pre-, post-opertive and status.The hypoglossal-facial nerve by "side- to-side" anastomisis was performed. All patients were followed-up.The mean time of follow-up was 8 months (ranged from 3 to 20 months). 12 patients were found a higher recovery of facial nerve function after the nerve anastomosis.16 patients who F wave of post-opertive were found a higher recovery compared to F wave of pre-opertive (P < 0.05). The hypoglossal-facial nerve by "side"-to-side anastomisis with pre-degenerated auto-nerve graft was effective for the treatment of peripheral facial palsy after CPA tumor resection, F wave can be used as one of the objective index for the effect of the operation.

Exclusively Endoscopic Resection of Cerebellopontine Angle (CPA) Tumors

Introduction: Endoscopy developed to an important technique in skull base surgery. In the posterior fossa the use of the endoscope is still limited. The question arises if the endoscope can be used more intensively also in lesions of the posterior fossa. Objective: To demonstrate the feasibility of tumor resection in the posterior fossa only by endoscopic visualization. To study its investigating limits, advantages, and problems. Methods: Two meningioma and five vestibular schwannoma (VS) patients were operated interdisciplinary in four hand technique in supine lateral position. Results: Mean age was 64.1 years. VS grew intra- and extrameatally, the meningioma were located lateral to the IAC, mean tumor diameter was 14.42 mm. Mean operation time was 263.6 minutes. There were no surgical complications. In two initial cases the microscope was used for final resection control. In all cases, the facial nerve could be preserved with normal function. The acoustic nerve was anatomically preserved in 6/7 cases. Hearing was preserved at the same level as preoperatively in 5/7 cases. Tumor resection was complete in 6/7 patients. In one patient a small contrast enhancing area in MRI is under control and stable. Mean follow-up was 33.7 months (minimum 14, maximum 71 months). Conclusion: Exclusively endoscopic resection of CPA tumors is feasible. Results are comparable to microscopic resections. Visualization in the posterior fossa is excellent, especially in the rostral area of the lesion and in the IAC. Retractors are not always necessary. Problems may occur with severe bleedings in the operation field.

Facial nerve anastomosis for facial paralysis resulting from surgery of cerebellopontine angle tumors

Objective To evaluate the efficiency and functional improvement of the facial nerve anastomosis for facial paralysis after cerebellontine angle (CPA) tumor surgery.Methods The clinical data of seven patients with facial paralysis after CPA tumors surgery underwent nerve anastomosis were analyzed retrospectively.House-Brackmann (H-B) grading was used to evaluate the pre-,post-operative and follow-up status.The end-end anastomosis of facial nerve was performed in one case,and facial-hypoglossal nerve anastomosis in six.Results All patients were followed-up.The mean time of follow-up was 23 months (ranged from 1 to 48 months).Among seven cases,the facial nerve function was improved in five cases,unchanged in one,and could not be evaluated in one because of short-time follow-up.The postoperative HB grades were Ⅱ in one case,Ⅲ in two and Ⅳ in two.Conclusions Facial nerve anatomosis was a useful treatment for facial paralysis after CPA tumors resection and could improve the facial function. Key words: Facial nerve injuries; Facial Palsy; Cerebellopontine angle; Nerve anastomosis

Purely Endoscopic Management of Vestibular Schwannomas

Introduction: Endoscopic resection of CPA tumors remains a scarcely reported entity. Several authors have described excellent results in utilizing endoscopy for MVD in cranial nerve compression syndromes, however, only a handful of reports currently exist describing CPA tumor resection in a purely endoscopic manner. This despite numerous articles indicating that endoscopy can improve visualization of neuro-vascular structures in the CPA. Among CPA tumors, vestibular schwannomas remain one of the most challenging tumors to resect and has rarely been described in a purely endoscopic technique. We report our results of resecting vestibular schwannomas in a purely endoscopic manner.

Znaczenie badań elektrofizjologicznych w diagnostyce guzów nerwu VIII

The most important for the diagnosis of vestibular schwannoma is MRI technic, which allows assessing its size and shape. The gold diagnostic standard includes also PTA, SD and ABR, nystagmography with calorics and VEMP. Nystagmography with calorics reflects the status of superior vestibular nerve. The sensitivity of calorics amounts to 61-87%. VEMPs reflect the status of interior vestibular nerve; its sensitivity is about 80%. The greatest diagnostic sensitivity shows ABR method, which is estimated for about 96-99%. analysis of PTA, ABR, VEMP and calorics results in smaller G1(≤10mm) and greater G2 (>11mm) tumors, and assessement of influence of the size of the tumor for auditory and vestibular function. MATHERIAL: PTA, ABR, VEMP and calorics results performed in 33 patients with CPA tumors. CPA tumors originate from inferior vestibular nerve in most cases; there is no statistical PTA differences in G1 and G2 groups; sensitivity of calorics (G1 53%, G2 95%), and ABR (G1 75%, G2 100%) depend on tumor size and tumor size has significant influence on results of both of these methods; sensitivity of VEMPs is similar in G1 and G2 groups (83% and 89%). there is no strict correlation between tumor origin and calorics and ABR results; greatest sensitivity in our material show VEMP, what is probably results of frequent tumors origin from inferior vestibular nerve.

Avoidance of Facial Nerve Injury in Lateral Skull Base Surgery

ABSTRACTIn the radiosurgery era, the treatment strategies for vestibular schwannoma have changed at most centers. This new paradigm holds that rational CPA tumor therapy requires balancing often competing goals of therapy, and the associated risks and benefits of different therapies or combination of therapies. The present review discusses this new paradigm and its specific implications for CPA tumor surgery. Inevitably, such a review will focus largely on minimizing facial nerve morbidity, as this is both the most modifiable risk, and the risk that is most reduced with the use of adjuvant therapies, such as stereotactic radiosurgery (like Gamma knife). The facts about facial nerve preservation in CPA tumor surgery will be reviewed, and methods for avoiding facial nerve morbidity will be discussed.

Preoperative Identification of the Facial Nerve in Patients with Large CPA Tumors Using Advanced MRI Tractographic Techniques

Preoperative Identification of the Facial Nerve in Patients with Large CPA Tumors Using Advanced MRI Tractographic Techniques

Pediatric CPA and IAC Tumors

Pediatric CPA and IAC Tumors

Facial Reanimation Results by Spinal Accessory Nerve–Facial Nerve (FN) Anastomosis

Methods: Between 1998 and 2008, 73 patients underwent major division accessory nerve–facial nerve anastomosis. The study consisted of 41 men and 32 women whose mean age was 54 years (range, 30–78 years). Eight patients had traumatic injuries (group I), and 65 had undergone CPA tumor removal (group II). The interval between FN loss and anastomosis ranged from 2 weeks to 14 months. For all group I patients, palsy arose immediately after the injury and lasted for 3–6 months. Total loss of FN function was confirmed by EMG. For group II: If during the operation total anatomical FN injury was visualized, then anastomosis was performed in 2–4 weeks; if anatomical FN structure was preserved, the anastomosis was performed in 6 months, unless FN function recovered (confirmed by EMG). All the patients underwent extracranial major division accessory nerve–facial nerve anastomosis.

Modifications of the Retrolabyrinthine Approach of CPA Tumors for Hearing Preservation

Introduction: The retrolabyrinthine approach is an alternative in CPA tumor types B and C for hearing preservation. In Germany, this approach is not as commonly used as it is in France, for example by the University Hospital at Bordeaux group. A trepanation of the head as well as a depression of the cerebellum can be avoided by entrance over the petrous bone. Method: The mastoidectomy is performed similarly to the surgical procedure used for the sacrotomy, or its decompression, with uncovering of the lateral semicircular canal. The bony bridge between the dura of the posterior fossa and the semicircular canal has to be removed. In contrast to the literature, the approach, with opening of the dura of the posterior fossa, can be performed with preservation of the upper petrous sinus and the endolymphatic sac. In case of type B tumors with an intracanicular tumor portion, the use of a 30-degree endoscope is mandatory. Results: From 2006 to 2008, 7 patients with a type B or C CPA tumor staged as II or III were treated alternatively by a modified retrolabyrinthine approach alone and by that approach combined with use of an endoscope. In all cases, the tumor was completely removed by preserving the facial and cochlear nerve function. In 3 cases, a navigation system was used to simplify and minimize the surgical approach and to reduce the bone work without uncovering the blue line of the lateral semicircular canal. Discussion: The clinical outcome of our own data compared with the literature showed no differences in 7th and 8th cranial nerve function and complete tumor removal. The additional use of a 30-degree endoscope improves the quality outcome of a complete tumor removal in the internal auditory canal.

Clinical Implications of Air Embolism in Patients with CPA Tumor Operated on in Sitting (or Semisitting) Position

Clinical Implications of Air Embolism in Patients with CPA Tumor Operated on in Sitting (or Semisitting) Position

Hemangiopericytoma of the cerebellopontine angle: a case report and review of the literature

Background Intracranial hemangiopericytoma represents a rare intracranial tumor that is typically difficult to distinguish from meningioma based on clinical presentation and radiographic findings. These inherently aggressive neoplasms have been observed to occur in numerous intracranial compartments; however, isolated involvement of the CPA is essentially unreported. The authors present a case of a young lady with presumed right acoustic schwannoma, which proved to be HPC on histopathology. The case is described; and a review of the literature pertaining to the diagnosis, optimal management, and follow-up for these lesions is provided. Case Description A 37-year-old Asian woman presented with a 7-month history of right ear and mandible numbness, as well as subjective hearing loss involving the right ear. Magnetic resonance imaging demonstrated the presence of a homogeneously enhancing extraaxial lesion in the right CPA, radiographically suggestive of an acoustic schwannoma. The lesion proved to be an intracranial HPC on histologic sections. Review of the neurosurgical literature yielded only one prior detailed account of HPC confined to the CPA. The patient underwent right retrosigmoid craniotomy for gross total resection of the mass, followed by stereotactic radiotherapy several weeks postoperatively. Conclusion Given the fundamentally different treatment approach for HPCs over other more common CPA tumors, it is imperative that the treating surgeon consider this rare diagnosis when evaluating patients with lesions localized to this area. Specifically, gross total resection, followed by adjuvant SRT, provides patients with the highest probability for disease-free survival, based on current evidence in the neurosurgical literature.

Analysis of Parameters Determining the Frequency and Intensity of Pneumatocele in Patients with CPA Tumor Operated in Sitting Position with Total Intravenous Anesthesia

Analysis of Parameters Determining the Frequency and Intensity of Pneumatocele in Patients with CPA Tumor Operated in Sitting Position with Total Intravenous Anesthesia

Analysis of Clinical Implications of Aeroembolism in Patients with CPA Tumor Operated in Sitting Position

Analysis of Clinical Implications of Aeroembolism in Patients with CPA Tumor Operated in Sitting Position

Analysis of Parameters Determining the Frequency and Intensity of Pneumatocele in Patients with CPA Tumor Operated in Sitting Position with Total Intravenous Anesthesia

Analysis of Parameters Determining the Frequency and Intensity of Pneumatocele in Patients with CPA Tumor Operated in Sitting Position with Total Intravenous Anesthesia

Cerebrospinal Fluid Cytology to Aid the Diagnosis of Cerebellopontine Angle Tumors

To determine if cerebrospinal fluid (CSF) cytology can be useful in the workup of patients with internal auditory canal/cerebellopontine angle (IAC/CPA) tumors and facial paralysis to diagnose metastatic disease before surgical intervention. Retrospective case series. Tertiary referral center. Patients who presented with or developed facial paralysis and IAC/CPA tumors. Lumbar puncture and CSF cytological analysis. Seven patients presented with or developed high-grade facial paralysis (greater than House-Brackmann Grade II). In the first patient, excision of the tumor revealed adenocarcinoma. All subsequent patients were evaluated with CSF cytological analysis. In five of these patients, cytological CSF analysis revealed malignant cells, suggesting a diagnosis of a metastatic lesion rather than acoustic neuroma. Primary neoplasms were identified in all but one of these patients. A sixth patient had metastatic breast cancer, but negative CSF cytology and a stable CPA tumor after radiation treatment. Two patients who were being conservatively followed up for their IAC/CPA tumor developed a nonprogressive but persistent mild Grade II facial weakness and underwent CSF analysis which tested negative. One patient had surgical resection with pathologic findings consistent with a typical acoustic schwannoma, and the other patient has been conservatively followed up without change. Our experience suggests that patients presenting with IAC/CPA tumors and progressive facial paralysis of House-Brackmann Grade III or greater should have a CSF cytological examination before surgical intervention to evaluate for a malignant process.

Cerebrospinal Fluid Cytology to Aid the Diagnosis of Cerebellopontine Angle Tumors

Objective: To determine if cerebrospinal fluid (CSF) cytology can be useful in the workup of patients with internal auditory canal/cerebellopontine angle (IAC/CPA) tumors and facial paralysis to diagnose metastatic disease before surgical intervention. Study Design: Retrospective case series. Setting: Tertiary referral center. Patients: Patients who presented with or developed facial paralysis and IAC/CPA tumors. Outcome Measure: Lumbar puncture and CSF cytological analysis. Results: Seven patients presented with or developed high-grade facial paralysis (greater than House-Brackmann Grade II). In the first patient, excision of the tumor revealed adenocarcinoma. All subsequent patients were evaluated with CSF cytological analysis. In five of these patients, cytological CSF analysis revealed malignant cells, suggesting a diagnosis of a metastatic lesion rather than acoustic neuroma. Primary neoplasms were identified in all but one of these patients. A sixth patient had metastatic breast cancer, but negative CSF cytology and a stable CPA tumor after radiation treatment. Two patients who were being conservatively followed up for their IAC/CPA tumor developed a nonprogressive but persistent mild Grade II facial weakness and underwent CSF analysis which tested negative. One patient had surgical resection with pathologic findings consistent with a typical acoustic schwannoma, and the other patient has been conservatively followed up without change. Conclusion: Our experience suggests that patients presenting with IAC/CPA tumors and progressive facial paralysis of House-Brackmann Grade III or greater should have a CSF cytological examination before surgical intervention to evaluate for a malignant process.

The role of conservative management of vestibular schwannomas.

Although microsurgery is generally regarded as the conventional treatment of choice for most vestibular schwannomas, there remains a group of patients in whom a conservative management approach may be a desirable alternative. The aim of this study was to determine the natural history and outcome following the conservative management of 72 patients with unilateral vestibular schwannomas. The reasons for conservative management included poor general health, age, patient preference, small tumour size, minimal or no symptoms, and tumour in the only/better hearing ear. The mean duration of follow-up was 39.8 months (range 12-194 months). All patients underwent serial magnetic resonance imaging (MRI) for assessment of tumour growth. Patients were deemed to have failed conservative management if there was evidence of continuous or rapid radiological tumour growth and/or increasing symptoms or signs. The mean tumour growth rate, according to the 1995 guidelines of the American Academy of Otolaryngology/Head and Neck Surgery, was 1.16 mm/year (range: 0.75 9.65 mm/year). Approximately 83% of tumours grew at < 2 mm/year. Significant tumour growth was seen in 36.4%, no or insignificant growth in 50%, and negative growth in 13.6% of tumours. The growth rate of CPA tumours (1.4 mm/year) was significantly greater than that of IAC tumours (0.2 mm/year) (P = 0.001). Failure of conservative management, in which active treatment was required, occurred in 15.3%. The outcome of these patients appeared to be as favourable to a comparable group who underwent primary treatment, without a period of conservative management. The mean growth rate of tumours in patients who failed conservative management (4.2 mm/year) was significantly greater than that in patients who did not fail (0.5 mm/year) (P < 0.01). No factors predictive of tumour growth or failure of conservative management were identified. Deterioration of mean pure tone average (0.5, 1, 2, 3 kHz) and speech discrimination scores occurred regardless of whether radiological tumour growth was demonstrated or not. This study suggests that in a select number of cases of vestibular schwannoma, a conservative management approach may be appropriate. Regular follow-up with serial MRI is mandatory. Deterioration of auditory function occurs even in the absence of tumour growth.