Magnetic resonance and computed tomographic image-directed stereotaxy for animal research

Current stereotactic frames for animal experimentation presume normal intracranial anatomy for atlas-directed probe placement. This is an invalid assumption for animal brain tumor models, where distortions of cerebral anatomy make image-directed stereotaxy necessary. To address this need, an accurate and reproducible magnetic resonance and computed tomographic compatible image-directed stereotactic apparatus for animal experimentation is presented.     

The long-term results of chymopapain chemonucleolysis for lumbar disc disease. Ten-year follow-up results in 268 patients injected at the Mayo Clinic

The long-term clinical outcome is evaluated for 268 patients after chymopapain chemonucleolysis for radicular complaints referrable to documented intervertebral disc disease. The follow-up period for 92% of these patients was 10 years. No complications due to chymopapain toxicity were observed; 80.1% of patients were relieved of their presenting radicular leg pain and 75.1% were employed at a capacity equal to or more strenuous than before injection. Chemonucleolysis was demonstrated to be a safe and effective treatment modality, with long-term results that compare favorably with those of similarly selected patients undergoing open surgical procedures. In the patients whose chymopapain therapy failed, the outcome of subsequent open surgical procedures was not necessarily compromised by prior chemonucleolysis. A higher rate of failure and subsequent surgical intervention was seen in those patients with injections performed soon after an unsuccessful open procedure on the same side and at the same interspace, those with workmen's compensation or litigation pending, those with a history of work-related injury, those whose employment involved heavy manual labor or extensive driving, and those whose preinjection spine x-ray films indicated retrograde spondylolisthesis.     

The long-term results of chymopapain. Ten-year follow-up of 268 patients after chemonucleolysis

The effect of chymopapain injection was investigated in myelographically confirmed intervertebral disc herniation in 268 patients after ten years. Mean age is 39.4 years, 178 males and 90 females. Sixty-two patients had compensation or litigation and 12 had prior lumbar spine surgery. Discography was performed in 223 patients, resulting in 134 one-level injections, 124 two-level injections, and ten three-level injections. Forty percent of the patients experienced postoperative muscle spasm for several days. No complications were seen in 241 patients (92%) who were available for follow-up examination at ten years; 86% had less leg pain, 82% were employed at a capacity equal to or greater than before injection, 9% were at a less strenuous job, 1% were disabled, and 8% had retired. In 22 patients treated surgically within one year of chemonucleolysis, disc-related pathology was present in 14 cases and spondylosis or spinal stenosis was present in seven cases. One had a negative exploration and continued to be disabled. Eight patients came to surgical intervention after one year because of persisting symptoms: four patients had disc protrusion, three had laminectomy and spinal fusion, and one had a decompressive laminectomy secondary to spondylotic change. Chemonucleolysis did not prejudice the outcome of subsequent surgical treatment with good results following this intervention. One tumor, a neurofibroma, was found in this study. Chemonucleolysis with chymopapain was a safe and effective treatment of radicular complaints caused by well-documented intervertebral disc herniation.     

Low-dose radiosurgery for benign intracranial lesions

This study assesses the efficacy and neurotoxicity of radiosurgical treatment of benign intracranial tumors using a linear accelerator, with relatively low dose and homogeneous dosimetry. Between June 1998 and July 2000, 27 patients were treated for benign lesions with radiosurgery using a 6-MV linear accelerator-based X-knife system and circular collimators. The lesions included schwannoma, meningioma, papillary cyst adenoma, and hemangioblastoma. Five patients had tissue diagnosis. The mean peripheral dose to the tumor margin was 12.8 Gy. The mean dose to the isocenter was 16.3 Gy. One to five isocenters were used to treat these lesions, with a mean of 10 arcs per isocenter and mean collimator size of 1.25 cm. Follow-up information was available on all patients, with a mean follow-up duration of 33 months. Six patients (22%) had improved symptoms and 21 (78%) had stable symptoms. Eight patients (30%) had regression of tumor and 19 had stable disease (70%). No patient had tumor progression, and Radiation Therapy Oncology Group (RTOG) grade III or IV toxicity did not occur in any patients. In 3 patients (11%), RTOG grade I or grade II neurotoxicity developed. Of these, one patient had worsening of a preexisting VIIth nerve deficit that required temporary oral methylprednisolone, and in two patients a mild trigeminal deficit developed that did not require any medical intervention. Low-dose homogeneous radiosurgery using a linear accelerator is an effective treatment for benign intracranial tumors. If lower, more homogeneous radiation doses produce responses as durable as higher doses, then toxicity might be further reduced.     

Treatment of glomus jugulare tumors in patients with advanced age: planned limited surgical resection followed by staged gamma knife radiosurgery: a preliminary report.

OBJECTIVE: To minimize treatment comorbidities in glomus jugulare tumor patients with advanced age while reducing pulsatile tinnitus and preserving or improving residual hearing using a limited middle ear/mastoid tumor resection and postoperative gamma knife radiosurgery to tumor remnants in the jugular foramen region. STUDY DESIGN: Retrospective consecutive case review of five patients. SETTING: Tertiary referral, academic medical center. PATIENTS: Patients with advanced age (mean, 69.6 yr; range, 61-78 yr) harboring symptomatic glomus jugulare tumors. INTERVENTION: All patients were treated with resection of middle ear and mastoid portions of tumor and subsequent gamma knife radiosurgery to jugular foramen portion of tumor. MAIN OUTCOME MEASURES: Length of hospitalization; hearing, pulsatile tinnitus, cranial nerve, and tumor control status. RESULTS: All patients were treated on an outpatient surgical basis without the need for blood transfusion. There were no incidents of a change in cranial nerve status (Cranial Nerves VII, IX, X, XI, and XII) in the immediate postoperative period. All patients had improvement or resolution of pulsatile tinnitus with preservation or improvement of preoperative hearing levels. Tumor volume was stable or reduced in all patients at mean follow-up of 19 months (range, 11-24 mo). Gamma knife radiosurgery (mean peripheral dose of 15 Gy) was not associated with any significant immediate or delayed complications. CONCLUSION: Short-term data reveals that staged microsurgical and radiosurgical therapy for glomus jugulare tumors in the symptomatic patient with advanced age is safe and yields favorable results regarding tinnitus, hearing, and cranial nerve status. Long-term data are needed to further evaluate the effectiveness of this treatment algorithm before extrapolating this treatment option to younger patients.