Treatment Of Skull Base Tumors Research Articles

TRANSORAL REMOVAL OF SKULL BASE AND C1-C2 VERTEBRAL BODY TUMOURS AND NONTUMOROUS PATHOLOGY IN THE CRANIOCERVICAL JUNCTION ACCOMPANIED BY CRANIOVERTEBRAL INSTABILITY

27 patients aged 2,5-61 years with skull base and C1-C2 vertebral body tumours and nontumorous pathology in the craniocervical junction underwent surgery. All patients revealed craniovertebral instability. To perform OSD we used autobone and metallic wire in 1 case, "Ventrofix" - 2; "CCD" - 9, "Vertex" - 15. In 26 cases OSD was followed by transoral tumor removal; in 1 - removal of the skull base chordoma spreading into C1-C2 segments was followed by OSD. In our practice we used original patent instruments, devices and surgical techniques. After the tumor has been removed, the skull defect hermetic closure and plasty were performed using the original patent technique for preventing postoperative CSF leakage as well as different glue compositions. This technique proved to shorten hospitalization period and reduce treatment costs as well as launch an early rehabilitation programme - on the 3d-4th day after operation. Use of new technologies in surgical treatment of skull base tumors invading upper cervical spinal segments accompanied by craniovertebral instability allowed to improve surgical outcome and start up early rehabilitation.

Carbon ion radiotherapy for pediatric patients and young adults treated for tumors of the skull base

The current study was conducted to evaluate the outcome of carbon ion radiotherapy (RT) in children and young adults with skull base chordomas and chondrosarcomas. Between 1997 and 2007, 394 patients were treated with carbon ion RT at Gesellschaft für Schwerionenforschung in Darmstadt, Germany. Of these patients, 17 patients were aged<or=21 years. Seventeen of these young patients were treated for chordoma or low-grade chondrosarcoma of the skull base and were analyzed in this study. Irradiation was performed after primary diagnosis in 14 patients (82%) and for recurrent tumors in 3 patients (18%). The authors applied a median total dose of 60 gray equivalents (Gy E) (range, 60-66.6 Gy E) in a fractionation of 7x3 Gy E per week of carbon ion RT using the raster scan technique. All patients were observed prospectively on a regular basis after carbon ion RT. The median follow-up time was 49 months. Treatment was well tolerated without severe side effects and could be completed on an outpatient basis in all patients without interruptions. One patient with chordoma developed tumor progression at 60 months after carbon ion RT. All other patients demonstrated no signs of tumor progression during follow-up. Despite its promising outcome in children and young adults with chordomas and chondrosarcomas, further evaluation in a larger patient collective is required. Randomized studies comparing the outcome after carbon ion RT with proton RT are especially needed to evaluate the role of particle beams in the treatment of skull base tumors in children and young adults.

Complications of Skull Base Surgery: An Analysis of 30 Cases

To evaluate the risk factors for perioperative complications among patients undergoing craniofacial resection for the treatment of skull base tumors. Retrospective analysis. The study group comprised 29 patients with skull base tumors (22 malignant and 7 benign) who underwent 30 craniofacial resections at Hokkaido University Hospital between 1989 and 2006. Of these cases, 21 had undergone prior treatment by radiation (16 cases), surgery (7 cases), or chemotherapy (1 case). Moreover, 19 needed extended resection involving the dura (11 cases), brain (5 cases), orbit (12 cases), hard palate (5 cases), skin (3 cases), or cavernous sinus (2 cases). Perioperative complications and risk factor associated with their incidence. Perioperative complications occurred in 12 patients (40%; 13 cases). There was a significant difference between complication rates for cases with and without prior therapy (52.4% vs. 11.1%). The complication rate for dural resection cases was 81.8%. There was a significant difference between complication rates for cases with and without dura resection. No postoperative mortality was reported. Craniofacial resection is a safe and effective treatment for skull base tumors. However, additional care is required in patients with extended resection (especially dural) and those who have undergone prior therapy.

Superficial temporal artery to middle cerebral artery bypass: past, present, and future

The aim of this study was to review the historical developments and current status of superficial temporal artery (STA) to middle cerebral artery (MCA) bypass. A literature review was performed to review the origins and current uses of the STA bypass procedure in neurosurgery. The idea of providing additional blood supply to the brain to prevent stroke and maintain neurological function has been present in the mind of neurosurgeons for many decades. In 1967 the first STA-MCA bypass was done by M. G. Yaşargil, and an enormous step was made into the field of microneurosurgery and cerebral revascularization. During the decades that followed, this technique was used as an adjuvant or a definitive surgical treatment for occlusive disease of the extracranial and intracranial cerebral vessels, skull base tumors, aneurysms, carotid-cavernous fistulas, cerebral vasospasm, acute cerebral ischemia, and moyamoya disease. With the results of the first randomized extracranial-intracranial (EC-IC) bypass trial and the development of endovascular techniques such as angioplasty for intracranial atherosclerotic disease and cerebral vasospasm, the indications for STA-MCA bypass became limited. Neurosurgeons continued to perform EC-IC bypasses as an adjuvant to clipping of aneurysms and in the treatment of skull base tumors and moyamoya disease; the procedure is less commonly used for atherosclerotic carotid artery occlusion (CAO) with definite evidence of hemodynamic insufficiency. The evidence that patients with symptomatic CAO and "misery perfusion" have an increased stroke risk has prompted a second trial for evaluating EC-IC bypass for stroke prevention. The Carotid Occlusion Surgery Study is a new trial designed to determine whether STA-MCA bypass can reduce the incidence of stroke in these patients. New trials will also reveal the role of the STA-MCA bypass in the prevention of hemorrhages in moyamoya disease. The role of STA-MCA bypass in the management of cerebrovascular disease continues to be refined and evaluated using advanced imaging techniques and by performing randomized trials for specific purposes, including symptomatic CAO.

A Treatment Planning Comparison of Combined Photon–Proton Beams Versus Proton Beams–Only for the Treatment of Skull Base Tumors

To compare treatment planning between combined photon-proton planning (CP) and proton planning (PP) for skull base tumors, so as to assess the potential limitations of CP for these tumors. Plans for 10 patients were computed for both CP and PP. Prescribed dose was 67 cobalt Gray equivalent (CGE) for PP; 45 Gy (photons) and 22 CGE (protons) for CP. Dose-volume histograms (DVHs) were calculated for gross target volume (GTV), clinical target volume (CTV), normal tissues (NT), and organs at risk (OARs) for each plan. Results were analyzed using DVH parameters, inhomogeneity coefficient (IC), and conformity index (CI). Mean doses delivered to the GTVs and CTVs with CP (65.0 and 61.7 CGE) and PP (65.3 and 62.2 Gy CGE) were not significantly different (p > 0.1 and p = 0.72). However, the dose inhomogeneity was drastically increased with CP, with a mean significant incremental IC value of 10.5% and CP of 6.8%, for both the GTV (p = 0.01) and CTV (p = 0.04), respectively. The CI(80%) values for the GTV and CTV were significantly higher with PP compared with CP. Compared with CP, the use of protons only led to a significant reduction of NT and OAR irradiation, in the intermediate-to-low dose (< or =80% isodose line) range. These results suggest that the use of CP results in levels of target dose conformation similar to those with PP. Use of PP significantly reduced the tumor dose inhomogeneity and the delivered intermediate-to-low dose to NT and OARs, leading us to conclude that this treatment is mainly appropriate for tumors in children.

Analysis of prognostic factors in 146 patients with anterior skull base sarcoma: An international collaborative study

Single-institutional studies lack sufficient power to assess the role of surgery and radiotherapy in the management of sarcomas involving the anterior skull base. For this study, an international collaborative study group analyzed a large cohort of patients who underwent surgery for the treatment of skull base tumors. A subset of 146 patients who had a histologic diagnosis of skull base sarcoma (SBS) formed the basis of this report. Most patients were aged > or =21 years (77%) and had stage IV disease (56%). Adjuvant radiotherapy was received by 35% of patients, and chemotherapy was received by 10% of patients. Orbital involvement was encountered in 53% of patients, involvement of the orbital wall was encountered in 46% of patients, and intracranial extension was encountered in 28% of patients. Positive microscopic margins were reported in 43% of patients (51 of 118 patients). Treatment-related complications were reported in 27% of patients, and postoperative mortality was reported in 1.4% of patients. With a median follow-up of 34 months, the 5-year overall, disease-specific, and recurrence-free survival rates were 62%, 64%, and 57%, respectively. Tumor grade and adjuvant radiotherapy were not significant predictors of survival. Prior radiotherapy, intraorbital extension, positive margins, and postoperative complications were significant predictors of reduced disease-specific survival on univariate analysis. The presence of positive/close margins, however, was the only independent predictor of poor overall, recurrence-free, and disease-specific survival on multivariate analysis (relative risk, 2.4; P = .006). The 5-year disease-specific survival rate was 77%, 43%, and 36% for patients with negative, close, and positive margins, respectively. The current results indicated that wide craniofacial resection with negative margins is an independent prognostic predictor of better outcome. Patients with positive margins have a high risk for tumor recurrence independent of tumor grade.

Evaluation of Endoscopy in Skull Base Surgery

Endoscopy has become widely used in the treatment of skull base tumors. However, the precise way in which endoscopy is useful and its advantages have not been thoroughly investigated. Using a cadaver model with an artificial sellar/suprasellar tumor, we investigated the exposure and the operability obtained in the trans-sphenoidal approach to the sella using a microsurgical trans-sphenoidal and an endoscopic approach. With small intrasellar lesions the endoscopic exposure is superior to the conventional one, while the same is not true with large sellar/suprasellar tumors. Operability, namely the ability to perform surgical maneuvers, is better with the microsurgical approach. We conclude that a microsurgically endoscopic-assisted approach may combine advantages of both techniques while minimizing their limitations.

Improved targeting device and computer navigation for accurate placement of brachytherapy needles

Successful treatment of skull base tumors with interstitial brachytherapy requires high targeting accuracy for the brachytherapy needles to avoid harming vital anatomical structures. To enable safe placement of the needles in this area, we developed an image-based planning and navigation system for brachytherapy, which includes a custom-made mechanical positioning arm that allows rough and fine adjustment of the needle position. The fine-adjustment mechanism consists of an XYZ microstage at the base of the arm and a needle holder with two fine-adjustable inclinations. The rotation axes of the inclinations cross at the tip of the needle so that the inclinational adjustments do not interfere with the translational adjustments. A vacuum cushion and a noninvasive fixation frame are used for the head immobilization. To avoid mechanical bending of the needles due to the weight of attached tracking markers, which would be detrimental for targeting accuracy, only a single LED marker on the tail of the needle is used. An experimental phantom-based targeting study with this setup demonstrated that a positioning accuracy of 1.4 mm (rms) can be achieved. The study showed that the proposed setup allows brachytherapy needles to be easily aligned and inserted with high targeting accuracy according to a preliminary plan. The achievable accuracy is higher than if the needles are inserted manually. The proposed system can be linked to a standard afterloader and standard dosimetry planning module. The associated additional effort is reasonable for the clinical practice and therefore the proposed procedure provides a promising tool for the safe treatment of tumors in the skull base area.

Microsurgery for Potential Radiosurgical Skull Base Lesions: A Retrospective Analysis and Comparison of Results

The outcomes of 26 complex skull base tumors treated with microsurgery were compared with the outcomes of similar tumors treated with radiosurgery as reported in the literature. The University neurosurgery database was searched for patients who underwent microsurgery for the treatment of skull base tumors between 1990 and 2001 at Louisiana State University Health Sciences Center in Shreveport, Louisiana. Twenty-six skull base meningiomas treated by microsurgery by the senior author (AN) were identified retrospectively. On imaging, the tumors were well defined and less than 3 cm in the greatest diameter, making them ideal candidates for a radiosurgical procedure had this modality been available. The follow-up and outcomes of these 26 patients were compared with the published outcomes of similar tumors treated with radiosurgery. Total excision was achieved in 17 (65.3 %) patients. Excision was subtotal in 9 (34.6 %) patients due to the critical locations of their tumors. The median hospital stay for these patients was 4 days (range, 3 to 12 days). Two patients (7.6 %) had transient cerebrospinal fluid leaks from the wound, and 2 (7.6 %) had transient facial paresis. Overall, preoperative symptoms improved in 23 (88.4 %) patients. The median follow-up was 56 months (range, 3 to 120 months). The overall survival rate for all was 87.2 +/- 3.7 % at 50 months. Two patients (7.6 %) subsequently underwent repeat surgery for a recurrent or progressive disease. The actuarial 8-year tumor control rate was 86.4 +/- 4.4 % using the Kaplan-Meier method. For small skull base tumors with benign histology, microsurgery is as safe and effective a treatment option as stereotactic radiosurgery. The symptomatic improvement in patients is better with microsurgery than with radiosurgery because the volume of the tumor is reduced immediately. A combined approach using both modalities is usually needed for larger tumors when attempts at total resection would jeopardize the neurologic function of the patient.

Tumors of the skull base in children and adolescents.

Published data obtained in children with tumors of the skull base are sparse. In the majority of the available reports, the authors focus on the technical application of skull base approaches, but they contribute a paucity of information on the management of specific tumors, especially malignant skull base lesions. The purposes of this report are to increase the collective experience with the treatment of these tumors and to identify successful management paradigms. The authors retrospectively reviewed the clinical records, pathological reports, and diagnostic images obtained in 24 children (< or = 19 years of age) with tumors arising from the cranial base in whom resection was part of their management between 1992 and 2002. Surgery-related complications and outcomes were analyzed with regard to tumor type and surgical approach. The median age of the group was 14 years. Tumors involved the anterior skull base in eight (33%), the middle skull base in 10 (42%), both the anterior and middle skull base in four (17%), and the posterior skull base in two patients (8%). Benign lesions were discovered in 11 patients (46%) and malignant neoplasms in 13 (54%). The tumors were most commonly of mesenchymal origin (21 [87.5%] of 24 tumors). Thirty surgical procedures were performed using a number of skull base approaches. A gross-total resection was achieved in 23 procedures (77%) and a subtotal resection in five (17%); a biopsy procedure was performed in one case; and the disease process could not be accessed in one case. One patient died in the perioperative period. Minor complications (Karnofsky Performance Scale score > or = 90, no prolongation of hospital stay, and no further surgery needed) occurred following 10 (33%) of the 30 surgical procedures. These affected 10 (42%) of the 24 patients and resulted in persistent or prolonged deficits in only five patients (21%). In nine patients (38%) the tumor recurred after a mean duration of 23 months. Skull base tumors in children affect mainly the anterior and middle cranial fossa. Sarcomas account for the majority of malignant tumors. Treatment of skull base tumors in children and adolescents needs to be tailored to patient age, tumor location, and tumor type.

157 oral The potential of intensity modulated proton therapy (IMPT) in the treatment of skull-base tumours

157 oral The potential of intensity modulated proton therapy (IMPT) in the treatment of skull-base tumours

Treatment of skull base tumors.

The rich multidisciplinary environment in which skull base surgery has developed has allowed for significant progress in the field and has improved patient outcomes. More precise and detailed anatomic dissection in the laboratories has provided surgeons with the benefit of undertaking the serious technical challenges encountered in the skull base. Significant work has been done and continues to be developed in the field of adjuvant treatments including radiotherapy, chemotherapy, and hormonal therapy. Using biologic end points and specific genetic targets in the tumors may further expand our management options in the future.

Skull base approaches and gamma knife radiosurgery for multimodality treatment of skull base tumors

Object. The purpose of this study was to evaluate descriptive data obtained in patients who had received multimodality treatment with resection and gamma knife radiosurgery (GKS) for skull base tumors. Retrospective data were collected from 71 patients with skull base tumors who were treated from November 1996 to December 2000, all of whom underwent follow-up evaluation at 1 year or more. Methods. Data were collected from hospital charts and office records, including patient age, tumor type and location, number of tumors, maximum radiation dose, estimated radiation dose to the periphery, tumor volume, and percentage of patients with tumors smaller or the same size at follow-up evaluation. Conclusions. Of the 71 patients with 1 year or more of follow up, 93% had tumor either the same size or smaller and 34% of these patients had a smaller tumor size. It is concluded that: 1) GKS with multimodality treatment is effective for control of skull base tumors; 2) the radiosurgical team should consider the benefits of GKS for treatment of any skull base tumor to afford optimum patient management; and 3) neurosurgeons involved with the management of skull base tumors should either be trained and proficient in GKS or work closely with a colleague trained in the technique. This will ensure proper consideration of both options, resulting in overall improved patient treatment.

Recent Advances in the Treatment of Skull Base Tumors Using Radiation

The evolution of technology has led to dramatic advances in the ability to treat tumors of the skull base, and the future of these devices seems bright. Only with time, however, will we be certain of their true role in the management of tumors of the skull base.

Stereotactic fractionated radiotherapy for chordomas and chondrosarcomas of the skull base

Purpose: To investigate the treatment outcome of patients suffering from skull base chordoma or chondrosarcoma after fractionated stereotactic radiotherapy. Methods and Materials: We report 45 patients treated for chordoma or chondrosarcoma with postoperative fractionated stereotactic radiotherapy between 1990 and 1997. Patients had CT and MRI for 3D treatment planning performed under stereotactic guidance. Median dose at isocenter was 66.6 Gy for chordomas and 64.9 Gy for chondrosarcomas. MRI imaging was obtained in intervals after therapy to evaluate local relapse. Survival was calculated according to the Kaplan-Meier method. Results: All chondrosarcomas had achieved and maintained local control and recurrence-free status at follow-up of 5 years. Local control rate of chordomas was 82% at 2 years and 50% at 5 years. Survival was 97% at 2 years and 82% at 5 years. At maximum follow-up of 8 years local control and survival rate of chordomas was 40% (82%). Clinically significant late toxicity developed in one patient. Conclusions: Our results demonstrate the feasibility of fractionated photon beam therapy and its success in the treatment of skull base tumors. Modern 3D treatment techniques provide superior results compared to conventional techniques. The role of high-precision radiotherapy compared to particle beam therapy in the treatment of these tumors is not yet fully clear and further research is needed.

Swallowing disorders in paralysis of the lower cranial nerves: a functional analysis.

Deficits of the lower cranial nerves (nerves IX, X, XI, and XII) occurring after treatment of skull base tumors may cause disabling swallowing disorders. To assess the mechanisms of swallowing disorders involved in such cases, we performed functional examinations: a videoendoscopic swallowing study and simultaneous manometry and videofluoroscopy in 7 patients. This study shows that the main mechanism of the swallowing disorders was a disturbance of the pharyngeal stage, including a decrease of pharyngeal propulsion, reduced laryngeal closure, and cricopharyngeal dysfunction, which led to aspiration. Decreased pharyngeal propulsion was found in 6 patients, with a very high correlation between fiberoscopy and simultaneous manometry-fluoroscopy. The responsibility of the upper esophageal sphincter in swallowing disorders was more difficult to assess. The role of the upper esophageal sphincter and pharyngeal propulsion in the onset of the problem is discussed in regard to the cricopharyngeal myotomy.

2103 Heavy ion therapy in the treatment of skull base tumors: Acute radiation induced toxicity

2103 Heavy ion therapy in the treatment of skull base tumors: Acute radiation induced toxicity

Neurophysiological monitoring during surgical treatment of skull-base tumors and vascular lesions

Various electrophysiological monitoring techniques are available for localizing and protecting cranial nerves and the brain stem during skull-base procedures. Separate neural pathways are used with each method, allowing for the simultaneous monitoring of different cranial nerves and brain stem tracts. Although monitoring of the facial nerve during resection of an acoustic neuroma is considered to be a standard of care, other monitoring techniques, such as tracking motor evoked potentials and visual evoked potentials, have not yet gained wide acceptance with neurosurgeons. This situation is in part attributable to technical factors that create difficulties in interpreting intraoperative changes in these responses. The use of individual techniques is usually based on the surgeon's level of comfort in attacking a given lesion and in his or her perception of the sensitivity and specificity of each type of electrophysiological monitoring.

Parasellar chondrosarcoma: total excision improves prognosis.

A case of parasellar chondrosarcoma is reported to highlight the recent advances in the surgical treatment of skull base tumours and the importance of total excision, which gives a good prognosis for a chondrosarcoma irrespective of grade.

The surgery of benign and malignant neoplasms adjacent to or involving the skull base

A group of patients who have undergone resection of benign and malignant neoplasms, either adjacent to or through the skull base, were evaluated to determine whether the long-term results justify the risks of such surgery. A total of 37 patients underwent 55 operations in a 6.5-year period from December 1979 to July 1986 at The Ohio State University. An analysis of the operative, perioperative, and long-term complications demonstrates that surgery is well-tolerated. The disease-free interval and survival rates for both benign and malignant neoplasms are encouraging and demonstrate curative potential even for those patients presenting with recurrent malignancies extending through the base of the skull. The interdisciplinary approach evaluated in this study is an effective modality in the treatment of skull base tumors, conferring a favorable risk-benefit ratio.