Yasuyuki Kinoshita, Atsushi Tominaga, Satoshi Usui, Kazunori Arita, Tetsuhiko Sakoguchi, Kazuhiko Sugiyama and Kaoru Kurisu
Patients with symptomatic Rathke's cleft cysts (RCCs) managed by surgical treatment often experience recurrence. The authors attempted to clarify the outcome of surgically treated RCCs over a long-term follow-up period.
Ninety-one consecutive RCC patients with a follow-up period of more than 12 months (mean 80.2 months, range 12–297 months) were retrospectively studied. The authors examined the clinical features and postoperative course of patients who experienced a reaccumulation of cyst contents visible on MRI after the initial surgery, and they investigated data from the patients who underwent reoperation for symptomatic recurrent RCCs.
Reaccumulation of cyst contents occurred in 36 patients (39.6%). In 34 of these patients, a reaccumulation occurred in the first 5 years after surgery. The initial cysts in these patients were most often large, with squamous metaplasia in the cyst walls. Thirteen patients (14.3%) with recurrent symptoms underwent a reoperation, and 10 of the 13 patients had a reaccumulation of RCCs within the 1st year after surgery. The reoperations were performed in the 1st year (61.5%) or several years later (23.1%). Patients were likely to initially have had a visual disturbance and the cyst walls likely included squamous metaplasia. However, no association was observed between the incidence of reaccumulation/reoperation of RCCs and the surgical procedure for RCCs.
The reaccumulation rate of RCC is high in the long-term period, and it is associated with the histological findings but not with the surgical procedure. Long-term monitoring, for a period of at least 5 years, should therefore be conducted to identify and assess any RCC reaccumulation.
Taiichi Saito, Manabu Tamura, Yoshihiro Muragaki, Takashi Maruyama, Yuichi Kubota, Satoko Fukuchi, Masayuki Nitta, Mikhail Chernov, Saori Okamoto, Kazuhiko Sugiyama, Kaoru Kurisu, Kuniyoshi L. Sakai, Yoshikazu Okada and Hiroshi Iseki
The objective in the present study was to evaluate the usefulness of cortico-cortical evoked potentials (CCEP) monitoring for the intraoperative assessment of speech function during resection of brain tumors.
Intraoperative monitoring of CCEP was applied in 13 patients (mean age 34 ± 14 years) during the removal of neoplasms located within or close to language-related structures in the dominant cerebral hemisphere. For this purpose strip electrodes were positioned above the frontal language area (FLA) and temporal language area (TLA), which were identified with direct cortical stimulation and/or preliminary mapping with the use of implanted chronic subdural grid electrodes. The CCEP response was defined as the highest observed negative peak in either direction of stimulation. In 12 cases the tumor was resected during awake craniotomy.
An intraoperative CCEP response was not obtained in one case because of technical problems. In the other patients it was identified from the FLA during stimulation of the TLA (7 cases) and from the TLA during stimulation of the FLA (5 cases), with a mean peak latency of 83 ± 15 msec. During tumor resection the CCEP response was unchanged in 5 cases, decreased in 4, and disappeared in 3. Postoperatively, all 7 patients with a decreased or absent CCEP response after lesion removal experienced deterioration in speech function. In contrast, in 5 cases with an unchanged intraoperative CCEP response, speaking abilities after surgery were preserved at the preoperative level, except in one patient who experienced not dysphasia, but dysarthria due to pyramidal tract injury. This difference was statistically significant (p < 0.01). The time required to recover speech function was also significantly associated with the type of intraoperative change in CCEP recordings (p < 0.01) and was, on average, 1.8 ± 1.0, 5.5 ± 1.0, and 11.0 ± 3.6 months, respectively, if the response was unchanged, was decreased, or had disappeared.
Monitoring CCEP is feasible during the resection of brain tumors affecting language-related cerebral structures. In the intraoperative evaluation of speech function, it can be a helpful adjunct or can be used in its direct assessment with cortical and subcortical mapping during awake craniotomy. It can also be used to predict the prognosis of language disorders after surgery and decide on the optimal resection of a neoplasm.