Harold L. Rekate
W. Jerry Oakes
Rémy Noudel, Mathieu Vinchon, Patrick Dhellemmes, Claude Fabien Litré and Pascal Rousseaux
In this study, the authors report their experience with the surgical treatment of intracranial teratomas with an emphasis on the indications for delayed resection after oncological treatment.
The authors retrospectively reviewed the cases of 14 children with intracranial teratomas. The mean age at diagnosis was 10.5 years (range 2 days–18 years), and 11 patients were male. The final histological analysis revealed pure mature teratoma in 5 cases, mixed teratoma with germinoma in 3 cases, and nongerminomatous malignant germ cell tumor in 6 cases. Thirteen patients underwent tumor resection, and these patients were divided into 2 subgroups according to the timing of surgery. In Group A, 10 patients underwent resection as the primary treatment because no tumor markers were detected in 4 patients, a teratomatous component was revealed on biopsy sampling in 3 patients, and a large tumor volume in 3 patients. In Group B, 3 patients underwent removal of residual pure mature teratoma after oncological treatment.
Seven of the 8 patients (87.5%) with pure mature teratomas or with mixed teratoma and germinoma are currently alive (mean follow-up of 9 years); the eighth patient died of postoperative meningitis. Two of the 6 patients (33%) with mixed nongerminomatous malignant germ cell tumors died of tumor progression regardless of the timing of surgery.
The results of this study support the belief that microsurgical removal is the only effective treatment for intracranial teratomas. Surgery may be performed as the primary therapy when there is evidence of a noninvasive teratoma, and as a secondary therapy if there is only a partial response to neoadjuvant therapy or if progression is observed in mixed malignant germ cell tumors.
Pierre-Hugues Roche, Vincent Lubrano, Rémy Noudel, Anthony Melot and Jean Régis
The authors undertook this study to examine the surgical approaches used to treat posterior petrous bone meningiomas at a single institution and retrospectively evaluate their surgical strategy based on a previously published classification.
Cases in which craniotomies were performed to treat posterior petrous bone meningiomas between 2002 and 2010 were retrospectively reviewed. Data were examined from 57 patients who were treated for 59 tumors. The tumors were classified into 3 types according to the location of their primary dural attachment: Type A, located around the porus trigeminus (33 tumors); Type M, located at the level of the porus of the internal auditory canal (IAC) (12 tumors); and Type P, located laterally to the IAC (14 tumors). The median tumor diameter was 34 mm (range 20–67 mm).
The choice of the approach was based on tumor location, as the displacement of vascular structures and cranial nerves was primarily determined by the site of dural attachment on the posterior petrous bone. An anterior petrosectomy was performed in 82% of Type A meningiomas, and a retrosigmoid approach was used in 86% of Type P meningiomas. The spectrum of approaches was less uniform for Type M meningiomas. Overall, total resection was obtained in 39% of all cases, and in 18%, 50%, and 86% of Type A, Type M, and Type P tumors, respectively. The postoperative mortality rate was 8.8% (5 deaths among 57 patients), and all 5 patients who died during the early postoperative period had large Type A tumors. At last follow-up, the functional preservation of the facial nerve was excellent in 49 (94%) of the 52 surviving patients.
The authors believe that proper selection of the approach favorably impacts functional outcome in patients undergoing surgery for the treatment of skull base tumors. In the authors' case series of posterior petrous bone meningiomas, Type P and most Type M tumors were safely managed through a regular retrosigmoid approach, whereas Type A tumors were optimally treated via an epidural anterior petrosectomy.
Rémy Noudel, Nicolas Jovenin, Cristophe Eap, Bernard Scherpereel, Laurent Pierot and Pascal Rousseaux
The chronic tonsillar herniation defining Chiari malformation Type I (CMI) is thought to result from overcrowding of a normally developing hindbrain within a congenitally small posterior cranial fossa (PCF) due to occipital hypoplasia. The goals in the present study were to authenticate the cranioencephalic disproportion in a group of patients with CMI and to discuss new developmental aspects according to which part of the occipital bone was underdeveloped.
The authors retrospectively examined a group of 17 patients with CMI. Measurements of osteotentorial and neural structures of the PCF were made on MR images of the brain. The results were compared with findings in 30 healthy controls by using the Mann-Whitney U-test.
Dimensions of the neural structures did not differ between the 2 groups of patients. The mean length of the basiocciput was significantly shorter in the CMI group (19.4 mm) compared with the control group (25.7 mm; p = 0.0003). The mean diameter of the foramen magnum was larger in the CMI group, but this difference was not statistically significant. The dimensions of the supraocciput and the mean angle of the cerebellar tentorium were identical in the 2 groups.
Data in this study support the idea that occipital hypoplasia is the main cause of overcrowding within the PCF. Basioccipital shortness is a cardinal feature of the resultant shallow PCF and could proceed from a congenital disorder of the cephalic mesoderm of the parachordal plate or occur later in the infancy because of premature stenosis of the sphenooccipital synchondrosis.
Rémy Noudel, Philippe Gomis, Gustavo Sotoares, Arnaud Bazin, Laurent Pierot, Jean-Pierre Pruvo, Régis Bordet and Pierre-Hugues Roche
The aim of this paper was to measure the posterior fossa (PF) volume increase resulting from a given-sized occipital craniectomy in Chiari malformation Type I surgery and to analyze its correlations with the PF size and the treatment response, with the perspective of tailoring the amount of bone removal to the patient-specific PF dimensions.
Between January 2005 and June 2006, 11 adult patients with symptomatic Chiari malformation Type I underwent a standardized PF decompression. A prospective evaluation with clinical examination, functional grading, and MR imaging measurement protocols was performed pre- and postoperatively. A method is reported for the measurement of PF volume (PFV) after surgery. The degree of PFV increase was compared with the preoperative size of the PF and with the clinical outcome.
All 11 patients improved postoperatively, with complete and partial recovery in 4 and 7 patients, respectively. No postoperative complication occurred after a mean follow-up period of 45 months.
The mean relative increase in PFV accounted for 10% (range 1.5%–19.7%) of the initial PFV; the increase was greater in cases in which the PF was small (r = −0.52, p = 0.09) and the basiocciput was short (r = −0.37, p = 0.2). A statistically significant positive correlation was found between the degree of PFV increase and the treatment response (p = 0.014); complete recovery was observed with a PFV increase of 15% and partial recovery with an increase of 7%.
The treatment response is significantly influenced by the degree of PFV increase, which is dependent on the size of the PF and the extent of the craniectomy, suggesting that the optimal patient-specific PFV increase could be predicted on the basis of preoperative MR imaging and enhancing the perspective that the craniectomy size could be tailored to the individual PFV.