NEUROSURGICAL FOCUS Neurosurg Focus 44 (4):E11, 2018 Safe maximal resection of primary cavernous sinus meningiomas via a minimal anterior and posterior combined transpetrosal approach Hiroki Morisako, MD, Takeo Goto, MD, Hiroki Ohata, MD, Sachin Ranganatha Goudihalli, MS, MCh, Keisuke Shirosaka, MD, and Kenji Ohata, MD Department of Neurosurgery, Osaka City University Graduate School of Medicine, Osaka, Japan OBJECTIVE Meningiomas arising from the cavernous sinus (CS) continue to be a significant technical challenge, and resection continues to carry a relatively higher risk of neurological morbidity in patients with these lesions because of the tumor’s proximity to neurovascular structures. The authors report the surgical outcomes of 9 patients with primary CS meningiomas (CSMs) that were surgically treated using a minimal anterior and posterior combined (MAPC) transpetrosal approach, and they emphasize the usefulness of the approach. METHODS This retrospective study included 9 patients who underwent surgery for CSM treatment between 2015 and 2016 via the MAPC transpetrosal approach. Two patients were men and 7 were women, with a mean age of 58.5 years (39–72 years). Five patients (55.5%) had undergone previous treatment. The surgical technique consisted of a temporo- occipito-suboccipital craniotomy and exposure of the posterolateral part of the CS via the presigmoidal MAPC approach. After opening Meckel’s cave and identifying the 3rd–5th cranial nerves in the prepontine cistern, Parkinson’s triangle and supratrochlear triangles were opened. Finally, the tumor occupying the posterolateral part of the CS was removed. RESULTS All lesions were safely and maximally removed, with preservation of external ocular movements and preoper- ative Karnofsky Performance Scale scores. The mean extent of resection was 77.0% (range 58.7%–95.4%). Six patients underwent adjuvant therapy in the form of stereotactic radiosurgery (SRS) or stereotactic radiotherapy (SRT) during the follow-up period; none of these patients experienced recurrence. CONCLUSION The authors conclude that the MAPC transpetrosal approach could be superior to other approaches for CSMs, as it provides direct visual access to the posterolateral portion of the CS. In their experience, this approach is an alternative and better option for safe maximal resection of CSMs. https://thejns.org/doi/abs/10.3171/2018.1.FOCUS17703 KEYWORDS transpetrosal approach; cavernous sinus; meningiomas ENINGIOMAS arising from the cavernous sinus fossa approach, but the optimal surgical approach remains (CS) are one of the most difficult and challeng- debatable.6,8,14,21,26,32,35 ing brain tumors to remove surgically. Over the The anterior and posterior combined transpetrosal ap- Mlast 3 decades, with long-term outcomes of CS meningio- proach, which consists of extensive resection of the pe- mas (CSMs), the surgical strategy has shifted from radical trosal bone to widen access to the petroclival junction resection to safe maximal removal to achieve local control with minimal retraction of the temporal lobe, has been of the tumor with or without additional radiation thera- described for the aggressive removal of petroclival le- py. 6,7, 9–11, 15–17, 19,24,26,29,30,31,33,35,37 Several surgical approaches sions.1 , 3 – 5 , 1 3 , 2 5 , 3 4 , 3 6 Despite various strategies described for have been reported for CSMs, including the frontotempo- this approach, it lacks popularity because of increasing ral orbitozygomatic approach, frontotemporal craniotomy rates of morbidity and mortality associated with its use in with or without orbital osteotomy, and extended middle the early years.1,2,22,27,36 ABBREVIATIONS CN = cranial nerve; CS = cavernous sinus; CSM = CS meningioma; ICA = internal carotid artery; KPS = Karnofsky Performance Scale; MAPC = minimal anterior and posterior combined; SPS = superior petrosal sinus; SRS = stereotactic radiosurgery; SRT = stereotactic radiotherapy. SUBMITTED November 20, 2017. ACCEPTED January 29, 2018. INCLUDE WHEN CITING DOI: 10.3171/2018.1.FOCUS17703. ©AANS 2018, except where prohibited by US copyright law Neurosurg Focus Volume 44 • April 2018 1 Unauthenticated | Downloaded 10/07/21 05:38 PM UTC H. Morisako et al. TABLE 1. Characteristics of 9 patients with primary cavernous sinus meningiomas resected via an MAPC transpetrosal approach Case Age (yrs), Preop Tumor EOR MIB-1 Postop Tumor Postop KPS Score No. Sex Previous Tx CND Diameter (mm) (%) (%) Vol (cm3) Postop CN Status RT Preop Postop 1 44, F None III 22 70 1.3 1.6 Complete recovery of III Yes 90 100 2 39, F None II 30 62 3.5 4.8 New CND III (transient) Yes 90 90 3 61, M None None 36 84 2.0 2 No new CND No 100 100 4 63, M None II, III, & VI 36 92 0.5 1.1 Partial improvement of VI No 90 90 5 68, F 1 op, 1 SRS V & VI 35 88 7.3 2 Partial improvement of V Yes 80 80 6 69, F 1 op, 1 SRS, III, V, & VI 30 59 2.0 5.9 No new CND No 80 80 1 SRT 7 44, F 1 op II & V 63 95 2.5 1.7 No new CND Yes 70 70 8 72, F 3 ops II & III 45 84 9.0 8 No new CND Yes 70 70 9 67, F 4 ops II, III, IV, 39 59 2.0 12.3 No new CND Yes 80 80 V & VI CND = CN deficit; EOR = extent of resection; RT = radiotherapy; Tx = treatment. To avoid the problems associated with this approach, sition. The head was fixed using 3-point fixation with the we have modified the technique by minimizing the petro- head rotated and vertex down to keep the temporal side of sectomy, making it what we call the minimal anterior and the head in the horizontal plane. The skin incision began posterior combined (MAPC) transpetrosal approach.18 We at the upper margin of the zygomatic arch anterior to the emphasize the fact that this approach offers a wider expo- tragus, turned 2–3 cm above the ear, and then descended sure of the posterolateral CS area and a unique view of the behind the posterior margin of the mastoid process. After CS with inferior-to-superior and posterior-to-anterior tra- the skin flap was raised, a temporalis fascia pericranial jectories, with a lower risk of injury to the neurovascular flap with a pedicle of the sternocleidomastoid muscle was structures around it. used for the dural reconstruction at the end of surgery to In this study, we describe the surgical technique and prevent postoperative CSF leakage. outcomes after performing the MAPC transpetrosal ap- proach for primary CSMs. Craniotomy A temporo-occipito-suboccipital craniotomy was per- Methods formed prior to the mastoidectomy. Burr holes were Between June 2015 and November 2016, 9 patients un- placed at 6 points, including anatomical landmarks, to derwent surgery via the MAPC transpetrosal approach for avoid injury to the sigmoid sinus. The first burr hole was CSMs at the Osaka City University Hospital. Two patients made at the asterion, the second at the intersection of the were men, and 7 were women; the mean patient age was supramastoid crest with the squamous suture, the third at 58.5 years (range 39–72 years). Five tumors (55.5%) were the mastoid emissary foramen, the fourth at the root of the zygoma, and the fifth and sixth at the anterior and poste- recurrences that had been previously treated either with rior aspects of the temporal bone, respectively. The first surgery or radiation therapy (Table 1). 3 burr holes are very important, as they are close to the All patients underwent preoperative CT scanning, sinus and have to be carefully drilled. The first burr hole MRI, and angiography. The mean tumor diameter was is usually made just above the lateral end of the transverse 37.3 mm (range 22–63 mm). Neuroradiologists indepen- sinus; the second, just anterior to the transverse-sigmoid dently evaluated the extent of tumor resection by compar- sinus junction; and the third, a few millimeters medial to ing the pre- and postoperative enhanced MR images that the posterior edge of the sigmoid sinus. were obtained within 1 week after surgery. For each pa- tient, the medical records were retrospectively reviewed to evaluate the status of the cranial nerves (CNs) and Karnof- Minimum Petrosectomy sky Performance Scale (KPS) score. After the temporo-occipito-suboccipital craniotomy was completed, the outer cortical bone of the mastoid por- Surgical Technique tion of the temporal bone was removed as a thin, triangular plate, a procedure referred to as a cosmetic mastoidecto- Much of the following descriptions of patient position- my. The procedure is not essential and is skipped in cases ing and skin incision, craniotomy, petrosectomy, dural in which the groove of the sigmoid sinus is too large. At opening, and reconstruction of the skull base were previ- 18,25 this point, the sigmoid sinus and transverse sinus–sigmoid ously published in our earlier study. sinus junction were safely exposed. Dural dissection from the petrous and mastoid portions of the temporal bone Patient Positioning and Skin Incision was then done for a safe and swift petrosectomy. In the The patient was placed in a semiprone park-bench po- middle fossa, the dura mater over the temporal base was 2 Neurosurg Focus Volume 44 • April 2018 Unauthenticated | Downloaded 10/07/21 05:38 PM UTC H. Morisako et al. gently reflected to fully expose the entire course of the pe- trous ridge and apex by cutting the middle meningeal ar- tery and dissecting the greater superficial petrosal nerve. In the posterior fossa, the presigmoid dura was carefully dissected from the posterior surface of the petrous por- tion of the temporal bone, and the entrance of the internal auditory canal was exposed epidurally by cutting the en- dolymphatic sac.