✓Stereotactic radiosurgery is a neurosurgical modality in which a target lesion can be irradiated while sparing normal brain tissue. In some respects, brain metastasis is well suited for radiosurgery, as metastatic lesions tend to be small and well circumscribed and displace (but do not infiltrate) normal brain tissue, facilitating the delivery of radiation. Advances in stereotactic radiosurgical planning, such as blocking patterns and beam shaping, have allowed further targeting of discrete lesions while minimizing the effect of radiation toxicity on the central nervous system. In this paper the authors review the radiobiology of brain metastases and stereotactic radiosurgical approaches that can be used to treat these tumors safely.
Jay Jagannathan, Jonathan H. Sherman, Gautam U. Mehta and Lawrence S. Chin
Jay Jagannathan, Jonathan H. Sherman, Tom Szabo, Christopher I. Shaffrey and John A. Jane Sr.
This study details long-term clinical and radiographic outcomes following single-level posterior cervical foraminotomy for degenerative disc or osteophyte disease.
The authors conducted a retrospective review of 162 cases involving patients treated by a single surgeon using a posterior cervical foraminotomy. Inclusion criteria were a minimum of 5 years' clinical and radiographic follow-up and unilateral single-level posterior cervical foraminotomy for degenerative disease between C-3 and C-7. Patients who had undergone previous operations, those who underwent bilateral procedures, and those who underwent foraminotomy as part of a larger laminectomy were excluded. The Neck Disability Index (NDI) was used for clinical follow-up, and radiographic follow-up was performed using static and dynamic lateral radiographs to compare focal and segmental alignment and changes in disc-space height.
The mean presenting NDI score was 18 (range 2–39). The most common presenting symptoms were radiculopathy (110 patients [68%]), neck pain (85 patients [52%]), and subjective weakness (91 patients [56%]). The mean preoperative focal angulation at the surgically treated level was 4.2° (median 4.1°, range 7.3–15.3°), and the mean preoperative segmental curvature between C-2 and C-7 was 18.0° (median 19.3°, range −22.1 to 39.3°). The mean postoperative NDI score was 8 (range 0–39). Improvement in NDI scores was seen in 150 patients (93%). Resolution of radiculopathy was experienced by 104 patients (95% of patients with radiculopathy). The mean radiographic follow-up was 77.3 months (range 60–177 months). No statistically significant changes in focal or segmental kyphosis or disc-space height were seen among the overall cohort with time (Cox proportional hazards analysis and Student t-test, p > 0.05). The mean postoperative focal angulation was 4.1° (median 3.9°, range −9.9° to 15.1°) and mean postoperative segmental angulation was 17.6° (median 15.4°, range −40.2 to 35.3°). Postoperative instability on dynamic imaging was present in 8 patients (4.9%); 7 of these patients were clinically asymptomatic and were treated conservatively, and 1 required cervical fusion. Postoperative loss of lordosis (defined as segmental Cobb angle < 10°) was seen in 30 patients (20%), 9 of whom had clinical symptoms and 4 of whom required further surgical correction. Factors associated with worsening sagittal alignment (Cox proportional hazards analysis, p < 0.05) included age > 60 at initial surgery, the presence of preoperative cervical lordosis of < 10°, and the need for posterior surgery after the initial foraminotomy
The posterior cervical foraminotomy is highly effective in treating patients with cervical radiculopathy and results in long-lasting pain relief and improved quality-of-life outcomes in most patients. Long-term radiographic follow-up shows no significant trend toward kyphosis, although select patient subsets (patients older than 60 years, patients who had previous posterior surgery, and patients with < 10° of lordosis preoperatively) appear to be at higher risk and require closer follow-up.