Objective
The anterior skull base region can be reached through different surgical approaches. The most frequently used are the pterional, bifrontal, and orbitozygomatic approaches. No previous reports describe the microsurgical technique when treating olfactory groove meningiomas (OGMs), anterior clinoidal meningiomas (ACMs), and tuberculum sellae meningiomas (TSMs)through the small lateral supraorbital (LSO) approach. The purpose here was to assess the reliability and safety of the LSO for the treatment of vascular and neoplastic lesions of the anterior skull base. The neuroanesthesia method when using this small approach is also presented. When needed, anterior clinoidectomy, intradurally or extradurally, is also possible through the LSO approach.
Patients and Methods
Between September 1997 and August 2010, we analyzed the clinical data, radiological findings, surgical treatment, anesthesiological procedure, histology, outcome, and long-term follow-up of 66 OGMs, 73 ACMs, 52 TSMs consecutive patients treated by the senior author (J.H.) through the LSO approach. Anterior clinoidectomy technique through the LSO is presented after reviewing 82 patients who underwent surgery for vascular and neoplastic lesions between June 2007 and January 2011. Altogether 273 patients of a total of 3000 LSO approaches were analyzed, and 15 videos were selected to show the approach and the microsurgical techniques used.
Results
Olfactory groove meningiomas: There was no surgical mortality. Six patients (9%) had CSF leakage, four (6%) had wound infections and cotton granulomas, and one (2%) had postoperative hematoma. The median Karnofsky score at discharge was 80 (range, 40-100). Six patients had residual tumors: three were re-operated on after an average of 21 (range, 1-41) months, one was treated with radiosurgery, and two were followed up. During the median follow-up of 45 (range, 2-128) months there were four recurrences (6%) diagnosed on average 32 (range, 17-59) months after surgery. Anterior clinoidal meningiomas: At three months after discharge, 60 patients (82%) had a good recovery, nine (12%) were moderately disabled, one (1%) presented with severe disability, and three (4%) died due to surgery-related complications. Sixteen patients (22%) had residual tumors, six of which required re-operation. Of 39 patients, pre-existing visual deficit improved in 11 (28%), worsened in four (5%), and three (4%) had de novo visual deficit. During the median follow-up of 36 (range, 3-146) months tumor recurred in three patients: two were followed up and one was reoperated.
Tuberculum sellae meningiomas: At three months postdischarge, 47 patients (90%) had a good recovery, four (8%) were moderately disabled, and one (2%) died 40 days after surgery of unexplained cardiac arrest. Of 42 patients, pre-existing visual deficit improved in 22 (42%), remained the same in 13 (25%), and worsened in seven (13%), and de novo visual deficit occurred in one patient (2%). Seven patients (13%) had minimal residual tumors, two of which required re-operation. During the median follow-up of 59 (range, 1-133) months tumor recurred in one of the patients who had received a second operation.
Anesthesia: Surgical conditions with slack brain were good in 154 meningioma patients. Slack brain was achieved by a head position elevated 20 cm above cardiac level in all patients; administering mannitol preoperatively in medium or large meningiomas (60 cases); propofol infusion (46 cases) or volatile anesthetics (107 cases) also in patients with large tumor (37 cases); and controlling intraoperative hemodynamics. The mean systolic blood pressure was 95-110 mmHg during surgery. The median intraoperative blood loss was 200 (range, 0-2000) ml and 9% of patients had red blood cell transfusion. One-hundred and fifty-seven patients (84%) were extubated on the day of the surgery. The median (25th/75th percentiles) time to extubation after surgery was 18 (8/105) min.
Anterior clinoidectomy: Eighty-two patients underwent anterior clinoidectomy: 45 patients (55%) were treated for aneurysms, 35 patients (43%) were treated for intraorbital, parasellar, and suprasellar tumors, and two patients (2%) presented with carotid-cavernous fistula. Intradural anterior clinoidectomy was performed in 67 cases (82%); in 15 cases (18%), an extradural approach was used. We performed a tailored anterior clinoidectomy: in five patients (6%), only the medial tip of the anterior clinoid process (ACP) was removed, in eight (10%) the head of the ACP, in 18 (22%) the body of the ACP, and in 51 (62%) the entire ACP. Four patients (5%) had new postoperative visual deficits and 12 (15%) improved their preoperative visual deficits after intradural anterior clinoidectomy. Extradural anterior clinoidectomy and use of ultrasonic bone device (Sonopet) may increase the risk of postoperative visual deficits. There was no mortality in the series.
Conclusions
The LSO approach can be used safely for OGMs, ACMs, and TSMs of all sizes, with a low mortality and a relatively low morbidity. Anterior clinoidectomy can be performed through the LSO approach. However, it is required only in selected cases and we prefer the intradural route. A slack brain is mandatory when performing the small LSO approach and can be achieved by patient positioning, propofol or inhaled anesthetics, preoperative mannitol, and optimizing cerebral perfusion pressure. With advancements in the neurosurgical field, the skull opening should be simple and as minimally invasive as possible. Surgical results with the simple, clean, and fast LSO approach are comparable with those achieved with more extensive, complex, and time-consuming approaches. We highly recommend the use of LSO for removal of vascular and neoplastic lesions of the anterior skull base.Ei saatavill
