Classification and quantification of the petrosal approach to the petroclival region

2000 ◽  
Vol 93 (1) ◽  
pp. 108-112 ◽  
Author(s):  
Michael A. Horgan ◽  
Gregory J. Anderson ◽  
Jordi X. Kellogg ◽  
Marc S. Schwartz ◽  
Sergey Spektor ◽  
...  
Keyword(s):  
Content Type ◽  
Petroclival Region ◽  
Nerve Preservation ◽  
Systematic Assessment ◽  
Central Target ◽  
Stereotactic Guidance ◽  
Transcrusal Approach ◽  
Retrolabyrinthine Approach ◽  
Partial Labyrinthectomy ◽  
Fine Print

Object. The petrosal approach to the petroclival region has been used by a variety of authors in various ways and the terminology has become quite confusing. A systematic assessment of the benefits and limitations of each approach is also lacking. The authors classify their approach to the middle and upper clivus, review the applications for each, and test their hypotheses on a cadaver model by using frameless stereotactic guidance.Methods. The petrosal approach to the upper and middle clivus is divided into four increasingly morbidity-producing steps: retrolabyrinthine, transcrusal (partial labyrinthectomy), transotic, and transcochlear approaches. Four latexinjected cadaveric heads (eight sides) underwent dissection in which frameless stereotactic guidance was used. An area of exposure 10 cm superficial to a central target (working area) was calculated. The area and length of clival exposure with each subsequent dissection was also calculated.The retrolabyrinthine approach spares hearing and facial function but provides for only a small window of upper clival exposure. The view afforded by what we have called the transcrusal approach provides for up to four times this exposure. The transotic and transcochlear procedures, although producing more morbidity, add little in terms of a larger clival window. However, with each step, the surgical freedom for manipulation of instruments increases.Conclusions. The petrosal approach to the upper and middle clivus is useful but should be used judiciously, because levels of morbidity can be high. The retrolabyrinthine approach has limited utility. For tumors without bone invasion, the transcrusal approach provides a much more versatile exposure with an excellent chance of hearing and facial nerve preservation. The transotic approach provides for greater versatility in treating lesions but clival exposure is not greatly enhanced. Transcochlear exposure adds little in terms of intradural exposure and should be reserved for cases in which access to the petrous carotid artery is necessary.

Transcrusal approach to the petroclival region with hearing preservation

2001 ◽  
Vol 94 (4) ◽  
pp. 660-666 ◽  
Author(s):  
Michael A. Horgan ◽  
Johnny B. Delashaw ◽  
Marc S. Schwartz ◽  
Jordi X. Kellogg ◽  
Sergey Spektor ◽  
...  
Keyword(s):  
Temporal Bone ◽  
Semicircular Canals ◽  
Hearing Preservation ◽  
Content Type ◽  
Petroclival Region ◽  
Transcrusal Approach ◽  
Partial Labyrinthectomy ◽  
Fine Print

✓ As a term, the “petrosal approach” to the petroclival region has a variety of meanings. The authors define a common nomenclature based on historical contributions and add new terminology to describe a technique of hearing preservation that allows for greater exposure of the petroclival region. The degree of temporal bone dissection defines five stages of operation. The authors used the second or “transcrusal” stage, in which the posterior and superior semicircular canals are sacrificed while preserving hearing, in six consecutive cases. Use of a common terminology ensures better understanding among surgeons. In the authors' hands, hearing has been successfully preserved in six patients after partial labyrinthectomy.

Facial nerve preservation during surgery for removal of acoustic nerve tumors

1982 ◽  
Vol 57 (6) ◽  
pp. 739-746 ◽  
Author(s):  
Richard H. Lye ◽  
John Dutton ◽  
Richard T. Ramsden ◽  
Joseph V. Occleshaw ◽  
Iain T. Ferguson ◽  
...  
Keyword(s):  
Facial Nerve ◽  
Petrous Bone ◽  
Ct Scans ◽  
Facial Weakness ◽  
Content Type ◽  
Nerve Preservation ◽  
Increased Risk ◽  
Acoustic Nerve ◽  
Facial Function ◽  
Fine Print

✓ A series of 33 patients with 35 acoustic nerve tumors is reviewed. Tumor size was estimated from computerized tomography (CT) scans, and its influence on anatomical and functional preservation of the facial nerve was assessed. Six tumors (one invading the petrous bone, three medium and two large tumors) were not detected on CT scans. The translabyrinthine approach was used in seven instances (one small and six medium tumors) and the suboccipital transmeatal approach for 28 tumors (seven medium and 21 large tumors). Anatomical preservation of the facial nerve was achieved in 83% of operations for tumor removal, two of which were subtotal. A further two patients underwent subtotal removal, but the facial nerve was destroyed. Large tumors carried an increased risk of damage to the facial nerve, but even in this group the nerve was preserved anatomically intact in 70% of cases. Damage to the facial nerve occurred more frequently in patients with preoperative evidence of facial weakness; however, this factor did not appear to influence functional recovery of the facial nerve, provided that the nerve was intact at the end of the operation. A simple grading system for facial nerve function is described. Only 76% of anatomically intact facial nerves showed any evidence of function 1 month after surgery. Postoperatively, facial function improved with time. At the latest review, 45% of these patients had normal facial function or mild facial weakness (Grades I and II).

Endoscopy of the posterior fossa and dissection of acoustic neuroma

1999 ◽  
Vol 91 (5) ◽  
pp. 776-780 ◽  
Author(s):  
Nebil Göksu ◽  
Yıldırım Bayazıt ◽  
Yusuf Kemaloğlu
Keyword(s):  
Posterior Fossa ◽  
Acoustic Neuroma ◽  
Residual Tumor ◽  
Lateral Aspect ◽  
Content Type ◽  
Retrolabyrinthine Approach ◽  
The Relationship ◽  
Neurovascular Structures ◽  
Internal Acoustic Canal ◽  
Fine Print

Object. The authors evaluated the importance of endoscopes in eliminating the disadvantages of the posterior fossa approach, such as the lack of adequate visualization of the lateral aspect of the internal acoustic canal (IAC).Methods. Between 1989 and 1998, 32 patients underwent removal of acoustic neuroma (AN) via a combined retrosigmoid—retrolabyrinthine approach. Endoscopes were used at different stages of the operation, and their use was evaluated with regard to elimination of the disadvantages of the posterior fossa approach. All patients in whom AN had been diagnosed underwent surgery in which a standard retrosigmoid—retrolabyrinthine approach was used. Standard sinus endoscopes of 0°, 30°, and 70° were introduced into the cerebellopontine angle before debulking the tumor, and the IAC was inspected at the end of the operation. Neurovascular integrity as well as the relationship between the AN and surrounding structures were evaluated. The IAC was inspected for residual tumor, and if any was found, endoscopically guided tumor dissection was performed.Conclusions. Endoscopes have facilitated an understanding of the anatomy between an AN and neighboring neurovascular structures. For surgery in which the posterior fossa approach is used, endoscopes can make operations safer by eliminating the disadvantages of the approach. In addition to allowing inspection of the fundus, it is possible to perform endoscopically guided tumor dissection within the IAC.

Intracranial Rosai—Dorfman disease treated with microsurgical resection and stereotactic radiosurgery

2003 ◽  
Vol 98 (1) ◽  
pp. 165-168 ◽  
Author(s):  
Constantinos G. Hadjipanayis ◽  
Ghassan Bejjani ◽  
Clayton Wiley ◽  
Toshinori Hasegawa ◽  
Melissa Maddock ◽  
...  
Keyword(s):  
Stereotactic Radiosurgery ◽  
Cervical Lymphadenopathy ◽  
Residual Tumor ◽  
Content Type ◽  
First Case ◽  
Excess Morbidity ◽  
Rosai Dorfman Disease ◽  
Microsurgical Resection ◽  
Partial Labyrinthectomy ◽  
Fine Print

✓ Sinus histiocytosis or Rosai—Dorfman disease (RDD) is a rare idiopathic histioproliferative disorder typically characterized by painless cervical lymphadenopathy, fever, and weight loss. Extranodal, intracranial disease is uncommon. In this report the authors describe the first case of intracranial RDD treated with stereotactic radiosurgery after resection. This 52-year-old man with known RDD presented with a 7-day course of fever, headache, diplopia, left facial paresthesias, and difficulty swallowing. No cranial nerve deficits were evident on examination, but right submandibular and inguinal node enlargements were noted. On neuroimaging, the patient was found to have a homogeneously contrast-enhancing petroclival lesion with extension into the left cavernous sinus. The patient underwent a combined left petrosal craniotomy and partial labyrinthectomy with duraplasty for biopsy sampling and partial microsurgical resection of the lesion. Microscopic examination of the biopsy specimen revealed the presence of a mixed cellular population with predominant mature histiocytes consistent with RDD. The residual tumor was treated with stereotactic radiosurgery 2 months after resection. On follow-up imaging the lesion had regressed significantly, with only slight dural enhancement remaining. Microsurgical resection for histological diagnosis, followed by stereotactic radiosurgery for residual tumor represents one treatment alternative in the management of intracranial RDD in which a complete resection carries the potential for excess morbidity.

Partial Labyrinthectomy Petrous Apicectomy Approach to the Petroclival Region: An Anatomic and Technical Study

Neurosurgery ◽  
2002 ◽  
Vol 51 (1) ◽  
pp. 147-160 ◽  
Author(s):  
Amitabha Chanda ◽  
Anil Nanda
Keyword(s):  
Cranial Nerves ◽  
Jugular Bulb ◽  
Microsurgical Anatomy ◽  
Petroclival Region ◽  
High Jugular Bulb ◽  
Before And After ◽  
Inaccessible Area ◽  
Retrolabyrinthine Approach ◽  
Brain Retraction ◽  
Partial Labyrinthectomy

Abstract OBJECTIVE 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. METHODS Bilateral stepwise dissections were performed on 15 formalin-fixed and dye-injected cadaveric heads (30 sides) under ×3 to ×40 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. RESULTS 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. CONCLUSION 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.

Sequential outer-table craniotomy in a hyperossified meningioma

1998 ◽  
Vol 88 (2) ◽  
pp. 346-348 ◽  
Author(s):  
Gary P. Colón ◽  
Donald A. Ross ◽  
Julian T. Hoff
Keyword(s):  
High Speed ◽  
Content Type ◽  
Tumor Mass ◽  
Undermined Area ◽  
Stereotactic Guidance ◽  
Fine Print ◽  
Outer Table

✓ A hyperossified meningioma with significant calvarial thickening is fairly common. Craniectomy of the involved region followed by cranioplasty is usually required to resect the bone overgrowth. However, in some cases, the hyperossified calvaria is too thick to allow safe penetration with a craniotome or trephine. In this report, the authors present a technique for preserving the outer calvaria while still resecting the majority of the underlying tumor mass. The key is to perform a craniotomy in a region adjacent to the hyperossified bone and to remove the tumorous, ossified inner table through this “window” by means of a high-speed drill. A second craniotomy can then be performed over the undermined area; this maneuver can be advanced and repeated until the tumor is resected. Frameless stereotactic guidance and microplates are useful in performing this procedure.

Tumors of the lateral wall of the cavernous sinus

1992 ◽  
Vol 77 (4) ◽  
pp. 508-514 ◽  
Author(s):  
Magdy El-Kalliny ◽  
Harry van Loveren ◽  
Jeffrey T. Keller ◽  
John M. Tew
Keyword(s):  
Cavernous Sinus ◽  
Cranial Nerve ◽  
Tumor Resection ◽  
Lateral Wall ◽  
Content Type ◽  
Nerve Preservation ◽  
Membranous Layer ◽  
Microsurgical Approach ◽  
Dural Wall ◽  
Fine Print

✓ The lateral dural wall of the cavernous sinus is composed of two layers, the outer dural layer (dura propria) and the inner membranous layer. Tumors arising from the contents of the lateral dural wall are located between these two layers and are classified as interdural. They are in essence extradural/extracavernous. The inner membranous layer separates these tumors from the venous channels of the cavernous sinus. Preoperative recognition of tumors in this location is critical for selecting an appropriate microsurgical approach. Characteristics displayed by magnetic resonance imaging show an oval-shaped, smooth-bordered mass with medial displacement but not encasement of the cavernous internal carotid artery. Tumors in this location can be resected safely without entering the cavernous sinus proper by using techniques that permit reflection of the dura propria of the lateral wall (methods of Hakuba or Dolenc). During the last 5 years, the authors have identified and treated five patients with interdural cavernous sinus tumors, which included two trigeminal neurinomas arising from the first division of the fifth cranial nerve, two epidermoid tumors, and one malignant melanoma presumed to be primary. The pathoanatomical features that make this group of tumors unique are discussed, as well as the clinical and radiological findings, and selection of the microsurgical approach. A more favorable prognosis for tumor resection and cranial nerve preservation is predicted for interdural tumors when compared with other cavernous sinus tumors.

The widened retrolabyrinthine approach: a new concept in acoustic neuroma surgery

1997 ◽  
Vol 86 (5) ◽  
pp. 812-821 ◽  
Author(s):  
Vincent Darrouzet ◽  
Jean Guerin ◽  
Naaman Aouad ◽  
Jaromir Dutkiewicz ◽  
Alexander W. Blayney ◽  
...  
Keyword(s):  
Facial Nerve ◽  
Hearing Aids ◽  
Postoperative Mortality ◽  
Fistula Formation ◽  
Content Type ◽  
Nerve Anastomosis ◽  
Postoperative Meningitis ◽  
Retrolabyrinthine Approach ◽  
Functional Surgery ◽  
Fine Print

✓ For many years, the retrolabyrinthine approach has been limited to functional surgery of the cerebellopontine angle (CPA). As a result of the increased surgical exposure, particularly the opening of the internal auditory meatus (IAM), the widened retrolabyrinthine technique permits tumor excision from both the CPA and the IAM, regardless of the histological nature of the tumor. The authors have treated 60 acoustic neuromas of varying sizes via this approach (6% intrameatal tumors; 30% > 25 mm in diameter). The postoperative mortality rate was 0%. The risk of fistula formation was 3.3%, and 3.3% of the patients suffered from postoperative meningitis. The results for facial nerve function were equivalent to those obtained previously via a widened translabyrinthine approach and those in a series treated via a suboccipital approach (80% with Grades I and II, 15% with Grade III, and 5% with Grades V and VI). One patient (1.7%) required a secondary hypoglossal—facial nerve anastomosis and had attained a Grade IV result 6 months later. Postoperatively 21.7% of these patients maintained socially useful hearing and 20% had mediocre hearing. Socially useful hearing was preserved in 50% of a subgroup of 20 patients who had both good preoperative hearing and a tumor that involved less than half of the IAM regardless of its volume. Additionally, 15% had mediocre hearing that could be improved with hearing aids. Because of its efficacy in preserving hearing, the authors favor the retrolabyrinthine over the occipital approach, with the latter being considered less subtle and more aggressive.

Resection of large vestibular schwannomas: facial nerve preservation in the context of surgical approach and patient-assessed outcome

2005 ◽  
Vol 102 (4) ◽  
pp. 643-649 ◽  
Author(s):  
Douglas E. Anderson ◽  
John Leonetti ◽  
Joshua J. Wind ◽  
Denise Cribari ◽  
Karen Fahey
Keyword(s):  
Facial Nerve ◽  
Vestibular Schwannomas ◽  
Facial Nerve Paralysis ◽  
Nerve Paralysis ◽  
Nerve Monitoring ◽  
Content Type ◽  
Nerve Preservation ◽  
Facial Nerve Monitoring ◽  
Facial Function ◽  
Fine Print

Object. Vestibular schwannoma surgery has evolved as new therapeutic options have emerged, patients' expectations have risen, and the psychological effect of facial nerve paralysis has been studied. For large vestibular schwannomas for which extirpation is the primary therapy, the goals remain complete tumor resection and maintenance of normal neurological function. Improved microsurgical techniques and intraoperative facial nerve monitoring have decreased the complication rate and increased the likelihood of normal to near-normal postoperative facial function. Nevertheless, the impairment most frequently reported by patients as an adverse effect of surgery continues to be facial nerve paralysis. In addition, patient assessment has provided a different, less optimistic view of outcome. The authors evaluated the extent of facial function, timing of facial nerve recovery, patients' perceptions of this recovery and function, and the prognostic value of intraoperative facial nerve monitoring following resection of large vestibular schwannomas; they then analyzed these results with respect to different surgical approaches. Methods. The authors retrospectively reviewed a database of 67 patients with 71 vestibular schwannomas measuring 3 cm or larger in diameter. The patients had undergone surgery via translabyrinthine, retrosigmoid, or combined approaches. Clinical outcomes were analyzed with respect to intraoperative facial nerve activity, responses to intraoperative stimulation, and time course of recovery. Eighty percent of patients obtained normal to near-normal facial function (House—Brackmann Grades I and II). Patients' perceptions of facial nerve function and recovery correlated well with the clinical observations. Conclusions. Trends in the data lead the authors to suggest that a retrosigmoid exposure, alone or in combination with a translabyrinthine approach, offers the best chance of facial nerve preservation in patients with large vestibular schwannomas.

Hearing restoration after resection of an intracanalicular vestibular schwannoma: a role for emergency surgery?

2002 ◽  
Vol 96 (4) ◽  
pp. 796-800 ◽  
Author(s):  
Lawrence Z. Meiteles ◽  
James K. Liu ◽  
William T. Couldwell
Keyword(s):  
Hearing Loss ◽  
Sensorineural Hearing Loss ◽  
Sudden Hearing Loss ◽  
Sensorineural Hearing ◽  
Therapeutic Window ◽  
High Dose ◽  
Rapid Improvement ◽  
Content Type ◽  
Nerve Preservation ◽  
Fine Print

✓ Patients with vestibular schwannomas (VSs) most commonly present with sensorineural hearing loss, which is often insidious or gradual. Up to 26% of patients may present with sudden hearing loss, however, which poses an important surgical challenge. Sudden hearing loss has been attributed to spasm or occlusion of the labyrinthine artery resulting from tumor compression, and it is usually treated with corticosteroids. Hearing preservation surgery is not usually attempted in patients who have poor or nonserviceable hearing preoperatively. The authors describe a 68-year-old man with complete deafness of the left ear since childhood, who developed sudden, profound sensorineural hearing loss in the right ear. Magnetic resonance imaging revealed a small right-sided intracanalicular tumor. Treatment with high-dose corticosteroids produced only minimal improvement in hearing. Subsequent emergency decompression and resection of a VS resulted in rapid improvement and restoration of hearing, with facial nerve preservation. Although most neurotologic lesions in patients with hearing in only one ear are managed nonsurgically, resection of small tumors in the setting of sudden hearing loss should be considered in selected cases. This finding indicates that a therapeutic window may exist during which sudden hearing loss caused by intracanalicular tumors is reversible.

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