Sandro Eustacchio

Gamma Knife radiosurgery of the glomus jugulare tumour - early multicentre experience.

Summary¶ Leksell Gamma Knife was used to treat 66 patients with glomus jugulare tumour at 6 European sites between 1992–1998. The age of the patients ranged between 18–80 years (median 54 years). Gamma Knife radiosurgery was a primary treatment in 30 patients (45.5%). Open surgery preceded radiosurgery in 24 patients (36.4%), embolisation in 14 patients (21.2%) and fractionated radiotherapy in 5 patients (7.6%). The volume of the tumour ranged 0.5–27 cm3 (median 5,7 cm3). The minimal dose to the tumour margin ranged between 10–30 Gy (median 16.5 Gy). After radiosurgery 52 patients were followed, the follow up period was 3–70 months (median 24 months). Neurological deficit improved in 15 patients (29%) and deteriorated in 3 patients (5,8%), one transient and two persistant. Neuroradiological follow up using MRI or CT was performed in 47 patients 4–70 months (median 24 months) after radiosurgery. Tumour size decreased in 19 patients (40%) while in the remaining 28 patients (60%) no change in the tumour volume was observed. None of the tumours increased in volume during the observation period. Control angiography was performed in 6 patients. Pathological vascularisation completely disappeared in one patient, reduced in two and there was no change in the remaining three. Radiosurgery proves to be a safe treatment for glomus jugulare tumour with no mortality and no acute morbidity. Because of its naturally slow growth rate, up to 10 years of follow up will be necessary to establish a cure rate after radiosurgery for these lesions.

A prospective cohort study of close interval computed tomography and magnetic resonance imaging after primary lumbar discectomy: factors associated with recurrent disc herniation and disc height loss.

Study Design. Prospective cohort study. Objective. We performed a prospective cohort study with standardized postoperative lumbar imaging every 3 months for a year then annually to assess the incidence and factors associated with same-level recurrent disc herniation. Summary of Background Data. The true incidence of same-level recurrent disc herniation after lumbar discectomy is unclear. Retrospective studies have reported widely varying incidences between 3% and 18%. Prospective controlled studies are lacking. Methods. A total of 108 patients undergoing first-time lumbar discectomy for refractory radiculopathy were enrolled. Baseline lumbar CT and MRI and standardized clinical data were assessed before surgery, and CT and MRI scans repeated 6 weeks, 3, 6, 9, 12, and 24-months after surgery and at the time of recurrent sciatica. Age, weight, preoperative disc volume, and height, volume of disc removed, and size of anular defect were compared with postoperative disc height loss and recurrent disc herniation using regression analysis. Results. One hundred patients (41 ± 10 years old) were available for 1-year (93%) and 76 (70%) for 2-year follow-up (mean follow-up: 25 ± 12 months). Improvement in all outcome measures was observed by 6 weeks after surgery (P < 0.005). An 18% loss of disc height was observed 3 months after surgery, progressing to 26% by 2 years. Eleven (10.2%) patients experienced recurrent disc herniation requiring revision discectomy a mean 10.5 months after surgery. Subjects with larger anular defects (P = 0.019) and with smaller percentage of disc volume removed (P = 0.028) were associated with an increased risk of recurrent disc herniation. Conversely, those from whom greater disc volumes were removed (P = 0.024) had more progressive disc height loss by 6 months after surgery. Conclusion. Larger anular defects and less disc removal increased the risk of reherniation. Greater volumes of disc removal were associated with accelerated disc height loss. In the setting of larger anular defects or less aggressive disc removal, concern for recurrent herniation should be increased during outpatient follow-up. In this situation effective anular repair may be helpful.

Gamma knife radiosurgery for glomus jugulare tumours.

Summary The aim of this clinical study was to determine the tumour control rate, clinical outcome and complication rate following gamma knife treatment for glomus jugulare tumours. Between May 1992 and May 1998, 13 patients with glomus tumours underwent stereotactic radiosurgical treatment in our department. The age of these patients ranged from 21 to 80 years. The male : female ratio was 2 : 11. Six patients had primary open surgery for partial removal or recurrent growth and subsequent radiosurgical therapy. Radiosurgery was performed as primary treatment in 7 cases. The median tumour volume was 6,4 cm3 (range: 4,6–13,7 cm3). The median marginal dose applied to an average isodose volume of 50% (30–50%) was 13,5 Gy (12–20 Gy). In 10 patients, a total of 48 MRI and CT follow-up scans were available. The remaining three patients have been excluded from the postradiosurgical evaluation since the observation time (t<12 months) was too short or patients were lost to follow up. The median interval from Gamma Knife treatment to the last radiological follow-up was 37,6 months (5–68 months). In 4 patients (40%) decreased tumour volumes were observed and in 6 cases (60%) the tumour size remained unchanged. Neurological follow-up examinations revealed improved clinical status in 5 patients (50%), a stable neurological status in 5 patients (50%) and no complications occurred. According to our preliminary experience Gamma Knife radiosurgery represents an effective treatment option for glomus jugulare tumours.

Cavernous Sinus Meningiomas – What Is the Strategy: Upfront or Adjuvant Gamma Knife Surgery?

43 patients with meningiomas of the cavernous sinus form the basis of this study. Two patients were treated with microsurgery alone, 17 patients were treated by Gamma Knife radiosurgery (GKRS) as a primary treatment modality, and 24 patients underwent a combined treatment of microsurgery followed by GKRS. Therefore, in 17 patients the diagnosis rested on clinical and radiological criteria alone. Cranial nerve disorders (CND) related to open surgical treatment were infrequent in this material (3 of 13 patients) due to deliberate strategies of partial or subtotal resection aimed at sparing cranial nerves from surgical maneuvers. In contrast, 6 of 11 patients, admitted for GKRS from other institutions suffered from considerable CND after open surgery and showed only partial improvement after GKRS. In all GKRS cases, no radiation-related complications were seen after a follow-up of 18–62 months (mean 39 months). Moreover, in all cases tumor control was obtained with a stable tumor volume in 63%, reduction of volume in 34.5% and a disappearance of tumor in 2.5%. GKRS is not only an additional treatment for meningiomas involving the cavernous sinus, but may be offered to the patient as an alternative primary treatment.

Staged radiosurgical treatment for large benign cerebral lesions

The purpose of this paper was to note a potential source of error in magnetic resonance (MR) imaging. Magnetic resonance images were acquired for stereotactic planning for GKS of a vestibular schwannoma in a female patient. The images were acquired using three-dimensional sequence, which has been shown to produce minimal distortion effects. The images were transferred to the planning workstation, but the coronal images were rejected. By examination of the raw data and reconstruction of sagittal images through the localizer side plate, it was clearly seen that the image of the square localizer system was grossly distorted. The patient was returned to the MR imager for further studies and a metal clasp on her brassiere was identified as the cause of the distortion.A-60-year-old man with medically intractable left-sided maxillary division trigeminal neuralgia had severe cardiac disease, was dependent on an internal defibrillator and could not undergo magnetic resonance imaging. The patient was successfully treated using computerized tomography (CT) cisternography and gamma knife radiosurgery. The patient was pain free 2 months after GKS. Contrast cisternography with CT scanning is an excellent alternative imaging modality for the treatment of patients with intractable trigeminal neuralgia who are unable to undergo MR imaging.The authors describe acute deterioration in facial and acoustic neuropathies following radiosurgery for acoustic neuromas. In May 1995, a 26-year-old man, who had no evidence of neurofibromatosis Type 2, was treated with gamma knife radiosurgery (GKS; maximum dose 20 Gy and margin dose 14 Gy) for a right-sided intracanalicular acoustic tumor. Two days after the treatment, he developed headache, vomiting, right-sided facial weakness, tinnitus, and right hearing loss. There was a deterioration of facial nerve function and hearing function from pretreatment values. The facial function worsened from House-Brackmann Grade 1 to 3. Hearing deteriorated from Grade 1 to 5. Magnetic resonance (MR) images, obtained at the same time revealed an obvious decrease in contrast enhancement of the tumor without any change in tumor size or peritumoral edema. Facial nerve function improved gradually and increased to House-Brackmann Grade 2 by 8 months post-GKS. The tumor has been unchanged in size for 5 years, and facial nerve function has also been maintained at Grade 2 with unchanged deafness. This is the first detailed report of immediate facial neuropathy after GKS for acoustic neuroma and MR imaging revealing early possibly toxic changes. Potential explanations for this phenomenon are presented.In clinical follow-up studies after radiosurgery, imaging modalities such as computerized tomography (CT) and magnetic resonance (MR) imaging are used. Accurate determination of the residual lesion volume is necessary for realistic assessment of the effects of treatment. Usually, the diameters rather than the volume of the lesion are measured. To determine the lesion volume without using stereotactically defined images, the software program VOLUMESERIES has been developed. VOLUMESERIES is a personal computer-based image analysis tool. Acquired DICOM CT scans and MR image series can be visualized. The region of interest is contoured with the help of the mouse, and then the system calculates the volume of the contoured region and the total volume is given in cubic centimeters. The defined volume is also displayed in reconstructed sagittal and coronal slices. In addition, distance measurements can be performed to measure tumor extent. The accuracy of VOLUMESERIES was checked against stereotactically defined images in the Leksell GammaPlan treatment planning program. A discrepancy in target volumes of approximately 8% was observed between the two methods. This discrepancy is of lesser interest because the method is used to determine the course of the target volume over time, rather than the absolute volume. Moreover, it could be shown that the method was more sensitive than the tumor diameter measurements currently in use. VOLUMESERIES appears to be a valuable tool for assessing residual lesion volume on follow-up images after gamma knife radiosurgery while avoiding the need for stereotactic definition.This study was conducted to evaluate the geometric distortion of angiographic images created from a commonly used digital x-ray imaging system and the performance of a commercially available distortion-correction computer program. A 12 x 12 x 12-cm wood phantom was constructed. Lead shots, 2 mm in diameter, were attached to the surfaces of the phantom. The phantom was then placed inside the angiographic localizer. Cut films (frontal and lateral analog films) of the phantom were obtained. The films were analyzed using GammaPlan target series 4.12. The same procedure was repeated with a digital x-ray imaging system equipped with a computer program to correct the geometric distortion. The distortion of the two sets of digital images was evaluated using the coordinates of the lead shots from the cut films as references. The coordinates of all lead shots obtained from digital images and corrected by the computer program coincided within 0.5 mm of those obtained from cut films. The average difference is 0.28 mm with a standard deviation of 0.01 mm. On the other hand, the coordinates obtained from digital images with and without correction can differ by as much as 3.4 mm. The average difference is 1.53 mm, with a standard deviation of 0.67 mm. The investigated computer program can reduce the geometric distortion of digital images from a commonly used x-ray imaging system to less than 0.5 mm. Therefore, they are suitable for the localization of arteriovenous malformations and other vascular targets in gamma knife radiosurgery.

Cranial Nerve Preservation after Radiosurgery of Vestibular Schwannomas

Radiosurgery is a management approach used to treat patients with vestibular schwannomas. The goals are long-term tumour growth control, maintenance of cranial nerve function and prevention of new deficiencies. We sought to determine long-term outcomes measuring the potential benefits against the neurological risks of primary radiosurgery. Gamma Knife radiosurgery was applied as a treatment modality for 289 patients with vestibular schwannomas from April 1992 to April 2002. The long-term results of 100 patients who underwent radiosurgery were evaluated. 60 patients received a primary treatment, 40 other cases presented with previously performed subtotal microsurgical resection or recurrence of disease (12-96 months, median 39). The median treatment volume was 3.4 ccm and the median dose to the tumour margin was 13 Gy. The median patient follow-up time was 76 months (range 60-120 months). Four tumours progressed after primary radiosurgery. Tumour control rate was 96%. Useful hearing (Gardner-Robertson I/II) was preserved in 16 patients (55%). Clinical neurological improvement occurred in 50%. Adverse effects comprised neurological symptoms (incomplete facial palsy) (House-Brackman II/III) in six cases (four recovered completely), mild transient trigeminal neuropathy in five cases, and morphological changes displaying rapid enlargement of preexisting macrocysts in two patients and tumour growth in two other patients. Microsurgical resection was performed in four cases (4%) and two patients underwent a shunting procedure because of hydrocephalus formation (2%). In patients who had undergone previous microsurgery, no new cranial nerve deficit was observed. Radiosurgery is an effective method for growth control of vestibular schwannomas and is associated with both a low mortality rate and a good quality of life. Accordingly, for the preservation of cranial nerve function radiosurgery is a useful method for the management of properly selected patients and is comparable to microsurgery.

Radiosurgery as alternative treatment for skull base meningiomas.

The effect of radiosurgical treatment of skull base meningiomas in 197 patients with a follow-up of at least 2 years was evaluated. Ninety-two of these patients had combined surgical and radiosurgical treatment, while Gamma Knife Radiosurgery (GKRS) was performed as primary treatment in 105 patients. Follow-up was available in 164 patients with intervals of 25-97 months (median 55 months) after GKRS. The imaging controls revealed decreased tumour size in 84 patients (51%), stable tumour volume in 76 ca ses (47%) and increased tumour size in 4 cases (2%). Neurological examinations showed improved neurological status in 58 cases (35%), stable clinical status in 100 patients (61%) and slight worsening in 6 cases (4%). Due to excellent tumour control rate, good clinical outcome and a low complication rate GKRS represents not only an attractive additional treatment option for basal meningiomas, but may even replace microsurgery in selected cases.

Radiosurgery of Vestibular Schwannomas: A Minimally Invasive Alternative to Microsurgery

Summary¶ From April 1992 till December 1998 stereotactic radiosurgery (Gamma Knife) was applied to 192 patients with vestibular schwannomas. 56 of them had radiosurgery as primary treatment modality and were followed-up for at least 4 years (48–80 months, median 62). Without fatal complications, control of tumour growth was achieved in all but three cases, useful hearing being preserved in more than one half of the patients (62%). The neurological state improved in 30 patients (54%). Irradiation-associated adverse effects (18%) comprised neurological signs (incomplete facial palsy, four cases (two recovered completely), and mild trigeminal neuropathy, three cases, respectively) and morphological changes (three patients) marked by an enlargement of pre-existing cystic components calling for additional surgical treatment: Microsurgical decompression was performed in two cases, the third patient underwent a shunting procedure because of hydrocephalus formation. Based on the present data, radiosurgery represents an effective treatment for vestibular schwannomas associated with an exceptionally low mortality rate and a good quality of life. With respect to the preservation of cranial nerve function, results are comparable to microsurgical resection. A short duration of hospitalization and a quick return to normal activities constitute further advantages and contribute to cost effectiveness in public health care.

Lumbar disc herniation mimicking meralgia paresthetica: case report

BACKGROUND Meralgia paresthetica, a syndrome of pain and/or dysesthesia in the anterolateral thigh, is normally caused by an entrapment of the lateral femoral cutaneous nerve (LFCN) at the anterior superior iliac spine. In a few cases compression of the nerve in the retroperitoneum has been reported to mimic meralgia paresthetica. CASE DESCRIPTION A 67-year-old woman presented with a 5-year history of permanent paresthesia in the anterolateral thigh. Motor weakness was not detected. Electromyography showed a neurogenic lesion at the level of L3. Lumbar spine MRI detected a foraminal-extraforaminal disc herniation at L2/L3, which was extirpated via a lateral transmuscular approach. The patient was free of symptoms on the first postoperative day. CONCLUSION In patients with meralgia paresthetica we emphasize a complete radiological investigation of the lumbar spine, including MRI, to exclude radicular compression by a disc herniation or a tumour at the level of L2 or L3.

Protecting facet joints post-lumbar discectomy: Barricaid annular closure device reduces risk of facet degeneration

Lumbar discectomy is an effective treatment for lumbar disc herniation (LDH). Although the majority of patients experience successful outcomes, a significant fraction will experience a recurrence of their back pain due to facet joint degeneration. Facet joint degeneration after discectomy may be the result of excessive nuclear removal, disc space narrowing, and annular injury. This study investigated whether implantation with the Barricaid annular closure device (ACD) during discectomy reduced the rate of facet degeneration. Inclusion criteria were primary lumbar disc herniation failing conservative treatment, Visual Analog Scale (VAS) Leg≥40/100, Oswestry Disability Index (ODI)≥40/100 and defects that were ≤60 mm2 (Barricaid arm only), and patient age 18-75. CT interpretations were collected preoperatively and 12 months post-discectomy. Patients implanted with Barricaid had significantly reduced rates and grades of facet degeneration than patients without Barricaid. Reinforcing the annulus fibrosus with Barricaid during lumbar discectomy may slow the progression of facet joint degeneration.