Retrolabyrinthine Approach Research Articles

Stage II vestibular schwannoma: Predictive factors for postoperative hearing loss and facial palsy

To assess predictive factors for deafness and facial palsy after vestibular schwannoma surgery on a translabyrinthine or retrolabyrinthine approach, and to compare sequela results to those for gamma knife radiosurgery. A retrospective study included 70 patients operated on for stage II vestibular schwannoma (Koos classification). Postoperative hearing was assessed on pure-tone average and speech discrimination score, and facial palsy on the House and Brackmann classification, preoperatively and at 1 year postoperatively. Various predictive factors were assessed for both. Statistical analysis used the Fischer exact test, with a significance threshold of P<0.05. Hearing was conserved in 18.9% of patients operated on with a retrolabyrinthine approach, with 8.1% conserving useful hearing. Facial function was conserved in 91.4%. Predictive factors for hearing conservation did not achieve statistical significance, but showed trends for: preoperative pure-tone average threshold≤30dB and speech discrimination score≥ 70%, age less than 55 years, tinnitus, nearly normal auditory brainstem response (ABR) latency, and homogeneous tumor on MRI. Predictive factors for conserved facial function likewise did not achieve statistical significance, but showed trends for: age less than 55 years, deafness of progressive onset, absence of cardiovascular risk factors, nearly normal ABR latency and tumor size<13.5mm on MRI. Facial nerve risk is largely the same with surgery or gamma knife radiosurgery. Concerning hearing, gamma knife radiosurgery seems to provide better hearing conservation, but only over the short term.

Retrolabyrinthine approach for surgical placement of auditory brainstem implants in children

Conclusion: The extended retrolabyrinthine approach (RLA) is a safe and reliable approach for auditory brainstem placement in children. The surgical landmarks to reach cochlear nucleus are adequately exposed by this approach. Objective: To describe a new approach option for auditory brainstem implants (ABIs) in children, highlighting the anatomical landmarks to appropriately expose the foramen of Luschka. Methods: Three prelingually deafened children consecutively operated for ABIs via the RLA. Results: ABI placement via the RLA was successfully performed in all children without any further complications except multidirectional nystagmus in one child. The RLA we employed differed from that used for vestibular schwannoma only in the removal of the posterior semicircular canal. The lateral and superior semicircular canals and the vestibule remained intact, and there was no need to expose the dura of the internal auditory meatus. The jugular bulb was completely exposed to allow adequate visualization of the ninth cranial nerve and cerebellar flocculus.

Management of Inverted Papilloma of the Temporal Bone

Objective: 1) Understand the clinical presentation, etiology, and histopathology of inverted papilloma of the temporal bone. 2) Discuss current treatment and management of inverted papilloma of the temporal bone as well as considerations for future management. Method: Inverted papilloma (IP), a benign neoplasm typically arising within the sinonasal tract, has rarely been reported occurring outside the sinonasal tract. Only 18 cases of temporal bone IP have been reported. We review our 2 cases of temporal bone IP and discuss their management. Results: Our cases demonstrate both primary and secondary temporal bone involvement. The first case was a primary lesion with atypical otoscopic appearance of a granular mass extending from the middle ear through a tympanic membrane perforation. This was managed with a tympanoplasty, canal wall up mastoidectomy, and facial recess approach. The second case presented as a subepithelial mass extending from the posterior wall of the ear canal after 3 resections of a sinonasal IP. Because of advanced bone destruction, extensive resection similar to a retrolabyrinthine approach was required, followed by tympanomastoid obliteration. Recurrence was monitored with baseline and follow-up PET-CT scans. Conclusion: Temporal bone IP is a rare neoplasm with no definitive treatment algorithm. We recommend aggressive surgical resection with close postoperative follow-up. PET-CT may be useful for identifying multicentric disease at presentation or for early identification of recurrent disease. HPV detection may identify IPs at risk for multicentric or recurrent disease.

Surgical Obliteration in Superior Petrosal Sinus Dural Arteriovenous Fistula

Superior petrosal sinus (SPS) dural arteriovenous fistula (DAVF) is one of tentorial DAVFs with significant morbidity, which usually drains into the petrosal vein and its tributaries. Unless there is a connection with venous sinus, surgical obliteration is required. We present two cases of SPS DAVF which were successfully treated with the presigmoid retrolabyrinthine approach.

Transcrusal approach to the retrochiasmatic region with special reference to temporal lobe retraction: an anatomical study

The retrochiasmatic region is one of the most challenging areas to surgically expose. The authors evaluated the transcrusal approach, which involves removal of the superior and posterior semicircular canal from the ampulla to the common crus, to expose the retrochiasmatic region and compared it with the retrolabyrinthine approach, both of which are a variation of the posterior petrosal approach with hearing preservation, with a special emphasis on the influence of temporal lobe retraction. Six sides of silicone-injected cadaveric heads were dissected using two approaches: the transcrusal approach and the retrolabyrinthine approach. For each craniotomy, 3 exposure parameters in the retrochiasmatic region were measured: (1) horizontal distance, (2) vertical distance, and (3) triangular area of exposure, at three different levels of temporal lobe retractions: 0, 5, and 10mm of retraction from the level of the tentorial incisura. Without temporal lobe retraction, only the transcrusal and not the retrolabyrinthine approach provided a direct exposure of the retrochiasmatic region, especially in the horizontal distance (p < 0.001). At all levels of temporal lobe retraction, the transcrusal approach provided greater exposure in the horizontal and vertical distances and in the area of exposure. Nonetheless, in the horizontal distance, the difference between the transcrusal and retrolabyrinthine approaches decreased along with increased temporal lobe retraction, and almost no difference was obtained at 10mm of retraction. Posterior petrosal approaches can provide an excellent exposure of the retrochiasmatic region. Of these two approaches, namely, transcrusal and retrolabyrinthine with hearing preservation, the transcrusal approach offers greater exposure than the retrolabyrinthine approach. The beneficial effect of partial labyrinthectomy of the transcrusal approach to the retrochiasmatic region is accentuated in the exposure of the horizontal distance with less temporal lobe retraction.

Modifizierter retrolabyrinthärer Zugangsweg bei Kleinhirnbrückenwinkeltumoren zum Hörerhalt

In an anatomical study including a CT scan of the cadaver sections by means of a virtual model analysis the option of a modified retrolabyrinthine passage to the cerebellopontine angle (CPA) preserving the Saccus endolymphaticus and the upper petrosus sinus was analysed. Due to the individual anatomical variations of the petrosus bone the results showed several limitations with regard to the retrolabyrintine passage to the CPA. The smallest distance between the dura of the posterior fossa and the posterior semicircular canal measured in a high resolution CT was of particular importance as to how much room was available for the surgical manipulation in the retrolabyrinthine space. As the back side angle to the petrosus bone is much flatter in a translabyrinthine approach than in a retrosigmoidal approach the internal auditory canal needed to be controlled by using a 30 degree endoscope. In five patients the translabyrinthine approach was modified by temporarily preserving the labyrinth in an effort to remove the CPA tumors. Based on our clinical experience and on the findings of the anatomical and radiological studies we eventually removed the CPA tumors type B2 or C3 in three patients preserving hearing by using a modified retrolabyrinthine approach.

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.

RETROLABYRINTHINE, TRANSLABYRINTHINE, AND TRANSCOCHLEAR APPROACHES

RETROLABYRINTHINE, TRANSLABYRINTHINE, AND TRANSCOCHLEAR APPROACHES Get access Neurosurgery, Volume 61, Issue suppl_4, October 2007, Pages S4-153–S4-168, https://doi.org/10.1227/01.NEU.0000296222.32201.22 Published: 01 October 2007

The Widened Retrolabyrinthine Approach in the Management of Vestibular Schwannoma

The Widened Retrolabyrinthine Approach in the Management of Vestibular Schwannoma

How to Avoid CSF Leak or Meningitis in the Postoperative Course of Vestibular Schwannoma: Our Experience of 345 Cases over 6 Years

Purpose: To report eradication of postoperative meningitis and CSF leak after vestibular schwannoma (VS) surgery and understand why and how it is possible to avoid such complications. Methods: A retrospective review in a tertiary referral center. We analyzed a series of 350 consecutive patients who underwent surgical removal of VS from 1999 to 2006 via transpetrosal approaches (translabyrinthine approach (TLA) or widened retrolabyrinthine approaches (WRLA)). At the time of closing the surgical approach, all opened mastoid air cells were filled with bone wax, with particular attention to those surrounding the internal auditory meatus. In WRLA, the middle ear was preserved and the aditus blocked by a single thick piece of pericranium, harvested before drilling. In TLA, the eustachian tube was tightly closed through the epitympanum with several small pieces of the same material after incus removal. In both, fibrin glue was used to stabilize the fat graft and prevent CSF leakage. This graft consisted of two separate pieces of fat. The first one was inserted between the posterior dura and the otic capsule (WRLA) or the rest of the labyrinth (TLA). The second one, which was larger, was installed to fill up the remaining bone defect and was secured with glue before wound closure. Antibioprophylaxis with cefazolin was systematically used. No lumbar drainage was used. Results: There were 169 men and 176 women. Mean age was 51.9 years (11 to 80 yrs). Tumor size was Koos stage 1 in 28 cases, stage 2 in 107 cases, stage 3 in 80 cases, and stage 4 in 130. TLA was used in 221 patients and WRLA in 124 cases. Mortality was absent. No patient had a CSF fistula. No meningitis was observed. Conclusion: Postoperative complications due to CSF fistulas may be avoided in transpetrosal approaches with a very simple but cautious closure technique.

The Widened Retrolabyrinthine Approach in the Management of Vestibular Schwannoma

The Widened Retrolabyrinthine Approach in the Management of Vestibular Schwannoma

Avantages de l’abord rétro-labyrinthique pour l’exérèse des méningiomes insérés au pourtour du coude du sinus latéral

To describe the retrolabyrinthine approach for the resection of 9 meningiomas inserted around the lateral sinus between the transverse and sigmoid parts, to discuss the value of this approach compared to the retrosigmoid approach for resection of meningioma in this localization and to review the literature. Retrospective study. Between 1988 and 2002, 9 patients (8 female, mean age 50 years) underwent surgery via the retrolabyrinthine approach for resection of meningiomas inserted around the lateral sinus between the transverse and sigmoid parts. Resection was total (8 Simpson I and 1 Simpson II) in all patients. In the early postoperative course, one patient was treated for meningitidis with an LCR leak and one patient present a temporary paresis of the vagus nerve. Mean follow-up was 5 years (6 months-10 years). All patients continued their pre-treatment occupation after surgery. No recurrence was observed. Two approaches can be used for resection of meningiomas in this localization. The retrosigmoid approach is a common neurosurgical approach exposure of the cerobellopontine angle. It is practised by most neurosurgeons. Via this approach, the cerebellar lobe must be pushed back so the arteries feeding the tumor are in the operative field at the end of the procedure. For numerous authors the operative field is too narrow. On the other hand, the retrolabyrinthine approach described in 1972 by Hitselberger and Pulec allows exposure of feeding arteries during the first steps of operation, an easier resection of meningioma insertion and better control of the lateral sinus. This approach can be enlarged to the retrosigmoid or the subtemporal anatomic region.

Preservação da audição em pacientes submetidos à cirurgia do shwannoma vestibular por acesso retrolabiríntico

A preservação da audição tem se tornado um objetivo na moderna cirurgia do schwannoma vestibular. OBJETIVO: O nosso estudo visa a analisar a audição pós-operatória de pacientes submetidos à cirurgia por acesso retrolabiríntico pressigmoideo. FORMA DE ESTUDO: Estudo de coorte contemporânea transversal. CASUÍSTICA E MÉTODO: Estudamos prospectivamente a audição de 41 pacientes submetidos à cirurgia para exérese de schwannomas vestibulares por acesso retrolabiríntico pressigmoideo entre 1994 e 2004 no Hospital das Clínicas da Universidade de São Paulo. Todos ospacientes apresentavam tumores unilaterais menores que 1.5 cm de diâmetro. Os seguintes parâmetros foram analisados em nosso protocolo: 1- remoção completa do tumor, 2- complicações e dificuldades intra-operatórias, 3- complicações pós-operatórios e 4- avaliação da audição após 90 dias da cirurgia. RESULTADOS: Total exposição do meato acústico interno com conseqüente remoção completa do tumor foi possível na maioria dos casos. Em apenas seis pacientes modificamos o acesso para um translabiríntico clássico no decorrer da cirurgia pela necessidade de ampliar o acesso ao fundo do meato. A audição foi preservada nos mesmos níveis anteriores à cirurgia em 34.1% dos casos. Nesta série nenhuma complicação severa ocorreu. CONCLUSÃO: O acesso retrolabiríntico pressigmoideo é seguro em relação ao nervo facial, possibilita a preservação da audição e apresenta pouca morbidade. Tem a grande vantagem de ser facilmente transformado em translabiríntico clássico quando maior exposição for necessária.

Surgery of cerebellopontine angle epidermoid cysts: Role of the widened retrolabyrinthine approach combined with endoscopy

Objectives To evaluate the use of the retrolabyrinthine approach (RLA) combined with endoscopy with particular reference to preservation of cranial nerve function and completeness of excision in surgery of epidermoid cysts. Methods A retrospective study was performed on a series of 8 consecutive patients of whom 7 have undergone surgery. Main outcome measures Measures include audiological and neurological status preoperatively and postoperatively, size of the lesion, the surgical approach, completeness of excision, and operative morbidity. Results The tumors were all large, ranging from 2 × 3 cm to 6 × 6 cm. Presenting symptoms were headache (75%), dysequilibrium (62%), trigeminal nerve palsy (38%), abducens nerve palsy (25%), and, rarely, auditory symptoms. Seven patients underwent surgery, 5 by the RLA, 1 by a translabyrinthine approach (TLA), and 1 by a transcochlear approach. Complete excision was achieved in 5 of the 7 patients. A transtentorial approach was combined in 2 cases (1 RLA, 1 TLA). Endoscopy was used in 3 cases. It allowed a complete tumor excision. One case of keratinous meningitis was observed. Trigeminal nerve function returned to normal in all patients. Postoperative facial nerve function was grade I in 5 cases and grade III in 2 cases. Hearing was preserved in 3 cases as class A, 1 case as class B. In the 2 cases presenting with abducens nerve palsy preoperative symptoms were initially aggravated before returning to normal function by 1 year postoperatively. The RLA with endoscopy allowed less invasive surgery and preservation of hearing in 4 of the 5 cases where it was attempted. Tumor control appeared better than with the suboccipital approach. Mortality and postoperative morbidity also appear reduced. Conclusion RLA combined with endoscopy should be considered as the standard approach for excision of epidermoid cysts. Extension of this approach into a TLA or transcochlear approach will depend on preoperative difficulties and preoperative hearing.

Retrolabyrinthine Craniectomy: The Unsung Hero of Skull Base Surgery

Despite being the foundation of, or supplement to, many skull base exposures, the retrolabyrinthine approach has not been adequately illustrated in the skull base literature. As an aid to skull base surgeons in training, this article provides a step-by-step description of the microsurgical anatomy and operative nuances of this important technique.

Commentary

The presigmoid retrolabyrinthine approach is very useful for small lesions involving the cerebellopontine angle and vestibulocochlear nerve complex and for vestibular neurectomy. It also can be combined with a supratentorial craniotomy to access lesions of the petroclival region that may extend above or below the tentorium. The benefit of the retrolabyrinthine approach is that the surgeon primarily works in the presigmoid region. Consequently, the posterior extent of the craniotomy and possibly some of the soft tissue dissection can be limited. The disadvantage is that access to the medial cerebellopontine angle is limited. An extension of this approach, the partial labyrinthectomy, has been reported to be associated with good preservation of hearing while improving access to the cerebellopontine angle. Although we have not attempted this technique at our institution, we are interested in the experience of other centers. Overall, this excellent article reminds both neurosurgeons and neuro-otologists of the versatility and usefulness of this approach.

Anatomy of the combined retrolabyrinthine–middle fossa craniotomy

The goal of combined retrolabyrinthine-middle fossa craniotomy is to provide exposure of both the middle and posterior cranial fossae via a partial petrosectomy and division of the tentorium. Its major benefits over others are that hearing and facial nerve function are preserved and only minimal brain retraction is required. The retrolabyrinthine approach involves a presigmoid posterior fossa craniotomy that preserves the structures of the inner ear. Additionally, a middle fossa craniotomy, extending to the zygomatic root, is performed to gain access to the superior aspect of the temporal bone in the middle cranial fossa. This approach works well in cases of lesions involving the petroclival junction, including petroclival meningiomas, trigeminal schwannomas, epidermoids, and large chondrosarcomas or chordomas with intradural components. The authors describe the surgical technique of this approach.

Partial labyrinthectomy petrous apicectomy approach to the petroclival region: an anatomic and technical study.

The petroclival region generally is thought to be an inaccessible area in the intracranial compartment. A number of ways of reaching this area during surgery have been described, including the presigmoid petrosal approach. The partial labyrinthectomy petrous apicectomy approach is a relatively new approach to this region and is a variant of the presigmoid petrosal approach. This study aims to demonstrate the technique and the microsurgical anatomy of the partial labyrinthectomy petrous apicectomy approach and to provide a quantitative study of its exposure to compare it with other common approaches to this region, particularly the presigmoid petrosal approach. Bilateral stepwise dissections were performed on 15 formalin-fixed and dye-injected cadaveric heads (30 sides) under x3 to x40 magnification. A temporal craniotomy was performed after a complete mastoidectomy. A partial labyrinthectomy and petrous apicectomy were performed next. The amount of dura exposed was measured before and after the partial labyrinthectomy and the petrous apicectomy. By measuring the angles of exposure, the approach was examined to analyze how much increased access was gained. This approach provided wide exposure to the petroclival region, the cerebellopontine angle, Meckel's cave, the cavernous sinus, and the prepontine region. On average, there was an increase of 10.8 mm in horizontal exposure as compared with the retrolabyrinthine approach. The average angle of vision achieved with the clival pit as the target was 58.9 degrees. In most of the specimens, an area from the IIIrd to the IXth cranial nerves was easily visible without any significant brain retraction. A high jugular bulb did not reduce the exposure. The partial labyrinthectomy petrous apicectomy approach converts two narrow tunnels into a wide corridor. It increases the angle of exposure markedly, providing easy and excellent exposure of the otherwise difficult-to-access petroclival region, and it may also preserve hearing.

Vestibular nerve section

Vestibular nerve section has been a reliable method to control dizziness caused by Meniere's disease. The surgery can be performed with 3 different approaches. Although the middle fossa and retrolabyrinthine approaches are well described, most vestibular nerve sections are now performed with the retrosigmoid approach. The techniques used for the surgery have changed little in the last 15 years. The control of vertigo is reported by several investigators to be in the range of 90% and appears to be stable over years of follow-up. Hearing loss still occurs in approximately one third of patients. The rate of complications remains low.

Modified retrolabyrinthine approach with partial labyrinthectomy: Anatomic study

This study was undertaken to evaluate the feasability of the modified retrolabyrinthine approach (traditional retrolabyrinthine approach plus resection of the posterior semicircular canal) to expose the entire fundus of the internal auditory canal (IAC). This approach is advocated by its proponents to manage acoustic neuromas reaching the lateral IAC and with the preservation of hearing as the goal. Little anatomic data directly estimate the limitations of this exposure. Measurements were recorded from 25 cadaver temporal bones dissected with this modified approach. The distances were taken between the porus acousticus (inferior and superior portions), the dome of the jugular bulb, the midportion of the sigmoid sinus, and the fundus of the IAC (inferior and superior portions). All of the measurements were then compared with those of the translabyrithine approach. The current study shows that despite the sacrifice of the posterior semicircular canal, the superior lateral fundus cannot be completely visualized. There is a distance (on average 1.1 mm) that differentiates the superior area of the IAC accessible with translabyrithine and modified retrosigmoid techniques. This value is smaller than that observed in the classic retrosigmoid approach indicating that the modified technique affords a more adequate, even if not ideal, exposure to minimize the risk of recurrence. The modified retrolabyrinthine approach provided an optimal exposure of the inferior half of the IAC. A superior blind area, smaller than that of the traditional retrolabyrinthine technique, cannot be completely approached via this route. We believe that this approach can be considered as an alternative technique in selected cases especially for tumors involving the inferior vestibular nerve. (Otolaryngol Head Neck Surg 2001;124:287-91.)