The Keyhole Retrosigmoid Approach to the Cerebello-Pontine Angle: Indications, Technical Modifications, and Results

ABSTRACT

Objectives: Establish the versatility and usefulness of the keyhole retrosigmoid approach to the cerebello-pontine angle (CPA) in various pathologies. Design: Prospective clinical study. Setting: Tertiary referral university hospital. Methods: One hundred twenty-one patients with various pathologies of the CPA underwent the relevant investigations and were operated upon by the retrosigmoid microendoscopic approach. The technical modifications and progression of our technique are described. Results: This group consisted of 121 patients (103 men and 28 women). The pathologies included were 60 acoustic neuromas, 28 vestibular neurectomies, nine meningiomas, and four arachnoid cysts. For nonmass lesions, no additional facial nerve injury or deterioration of hearing occurred. Total excision of mass lesions was achieved in 94.5% of cases. Facial nerve integrity was preserved in 92.3% of cases with mass lesions and permanent facial paralysis occurred in 8.3%. There were no mortalities, and the most frequent complication was a delayed cerebrospinal fluid leak from the site of the wound (15%), which was managed conservatively in all cases. Conclusions: The keyhole retrosigmoid approach is a versatile one. It can be used to deal with different pathologies through a unified access, and with the increasing exclusive use of endoscopes, a truly minimally invasive surgery can be achieved.

KEYWORDS

Retrosigmoid approach - acoustic neuromas - vestibular neurectomy - microvascular decompression

REFERENCES

• 1 Bennett M, Haynes D S. Surgical approaches and complications in the removal of vestibular schwannomas.  Otolaryngol Clin North Am. 2007;  40 589-609
• 2 Magnan J, Chays A, Lepetre C, Pencroffi E. Surgical perspectives on endoscopy of the cerebellopontine angle.  Am J Otol. 1994;  15 366-370
• 3 Magnan J, Sanna M. Endoscopy in Neuro-otology. New York; Thime Stuttgart 1999
• 4 Badr-El-Dine M, El-Garem H, Talaat A, Magnan J. Endoscopically assisted minimally invasive microvascular decompression of hemifacial spasm.  Otol Neurotol. 2002;  23 122-128
• 5 El-Garem H F, Badr-El-Dine M, Talaat A M, Magnan J. Endoscopy as a tool in minimally invasive trigeminal neuralgia surgery.  Otol Neurotol. 2002;  23 132-135
• 6 Magnan J, Barbieri M, Mora R et al.. Retrosigmoid approach for small and medium-sized acoustic neuromas.  Otol Neurotol. 2002;  23 141-145
• 7 Wackym P A, King W A, Meyer G A, Poe D S. Endoscopy in neuro-otologic surgery.  Otolaryngol Clin North Am. 2002;  35 297-323
• 8 Miyazaki H, Deveze A, Magnan J. Neuro-otologic surgery through minimally invasive retrosigmoid approach: endoscope assisted microvascular decompression, vestibular neurotomy, and tumor removal.  Laryngoscope. 2005;  115 1612-1617
• 9 Samii M, Gerganov V, Samii A. Improved preservation of hearing and facial nerve function in vestibular schwannoma surgery via the retrosigmoid approach in a series of 200 patients.  J Neurosurg. 2006;  105 527-535
• 10 Behr R, Muller J, Shehata-Dieler W et al.. The High Rate CIS Auditory Brainstem Implant for Restoration of Hearing in NF-2 Patients.  Skull Base. 2007;  17 91-108
• 11 Goksu N, Bayazit Y, Kemaloglu Y. Endoscopy of the posterior fossa and endoscopic dissection of acoustic neuroma.  Neurosurg Focus. 1999;  6 e15
• 12 Colletti V, Fiorino F. Middle fossa versus retrosigmoid-transmeatal approach in vestibular schwannoma surgery: a prospective study.  Otol Neurotol. 2003;  24 927-934
• 13 Mangham Jr C A. Retrosigmoid versus middle fossa surgery for small vestibular schwannomas.  Laryngoscope. 2004;  114 1455-1461
• 14 Hori T, Okada Y, Maruyama T, Chernov M, Attia W. Endoscope-controlled removal of intrameatal vestibular schwannomas.  Minim Invasive Neurosurg. 2006;  49 25-29
• 15 Shahinian H K, Eby J B, Ocon M. Fully endoscopic excision of vestibular schwannomas.  Minim Invasive Neurosurg. 2004;  47 329-332
• 16 Gerganov V M, Romansky K V, Bussarsky V A, Noutchev L T, Iliev I N. Endoscope-assisted microsurgery of large vestibular schwannomas.  Minim Invasive Neurosurg. 2005;  48 39-43
• 17 Elsmore A J, Mendoza N D. The operative learning curve for vestibular schwannoma excision via the retrosigmoid approach.  Br J Neurosurg. 2002;  16 448-455
• 18 Chen L H, Liu Y S, Yuan X R et al.. Keyhole microsurgery for acoustic neurinomas through suboccipital retrosigmoid sinus approach.  Ai Zheng. 2002;  21 1136-1140
• 19 Tan C, Brookes G B. The endoscopic technique utilized in removal process of acoustic neuroma by retrosigmoid approach.  Lin Chuang Er Bi Yan Hou Ke Za Zhi. 2003;  17 25-26
• 20 Wackym P A, King W A, Poe D S et al.. Adjunctive use of endoscopy during acoustic neuroma surgery.  Laryngoscope. 1999;  109 1193-1201
• 21 Göksu N, Yilmaz M, Bayramoglu I, Aydil U, Bayazit Y A. Evaluation of the results of endoscope-assisted acoustic neuroma surgery through posterior fossa approach.  ORL J Otorhinolaryngol Relat Spec. 2005;  67 87-91
• 22 Kabil M S, Shahinian H K. A series of 112 fully endoscopic resections of vestibular schwannomas.  Minim Invasive Neurosurg. 2006;  49 362-368
• 23 Goksu N, Bayazit Y A, Bayramoglu I, Isik B, Yilmaz M, Kurtipek O, Uygur M. Surgical exposure in retrosigmoid approach: do we need cerebellar retractors?.  Surg Neurol. 2006;  65 631-634
• 24 Yamashima T, Lee J H, Tobias S et al.. Surgical procedure “simplified retrosigmoid approach” for C–P angle lesions.  J Neuroscience. 2004;  11 168-171