title: Neurological complications and symptom resolution following Gamma Knife surgery for brain metastases 2 cm or smaller in relation to eloquent cortices.
abstract: OBJECTIVE
  Reports on resection of tumors in or near eloquent cortices have noted neurological complications in up to 30% of patients. This paper contains an analysis of symptom resolution and neurological morbidity following 20-Gy Gamma Knife surgery (GKS) for supratentorial brain metastases < or = 2 cm in greatest diameter.
  
  
  METHODS
  The authors performed a retrospective analysis of 98 consecutively treated adults (33 men and 65 women with a median age of 61.4 years at the time of GKS) with Karnofsky Performance Scale score > or = 60, who underwent GKS for supratentorial brain metastases < or = 2 cm in diameter. Lesion location was classified as noneloquent (Grade I), near eloquent (Grade II), or eloquent (Grade III), in accordance with the grading system developed by the group at M. D. Anderson Cancer Center. Following treatment, the patients underwent MR imaging and clinical examinations at 6 weeks and every 3 months thereafter.
  
  
  RESULTS
  Ninety-eight patients underwent 20-Gy GKS for 131 metastases at initial presentation and 31 patients underwent salvage 20-Gy GKS for 76 new lesions, for a total of 207 lesions (mean lesion volume 0.44 cm3). Lesions were classified as follows: Grade I, 96 (46.4%); Grade II, 51 (24.6%); and Grade III, 60 (29%). Fifteen patients (2 with Grade II and 13 with Grade III lesions) presented with deficits referable to their lesions, yielding pre-GKS deficit rates of 7.2% per lesion and 15.3% per patient. The pre-GKS deficits improved or resolved in 10 patients (66.7%) at a median time of 2.8 months and remained stable in 3 patients (20%). Two patients (13.3%) experienced worsened neurological deficits. One patient who was neurologically intact prior to treatment developed a new hemiparesis (1 of 83 patients [1.2%]). The rates of permanent neurological deterioration following GKS for Grades I, II, and III lesions were 0% (0 of 96 tumors), 2% (1 of 51), and 3.3% (2 of 60), respectively. The pre-GKS neurological deficits and larger lesions were the most significant risk factors for post-GKS neurological deterioration.
  
  
  CONCLUSIONS
  Gamma Knife surgery performed using a 20-Gy dose provides amelioration of neurological deficits from brain metastases that are < or = 2 cm in diameter and located in or near eloquent cortices in nearly two-thirds of patients with a low incidence of morbidity. Consistent with the surgical literature, higher rates of neurological complications were observed as proximity to eloquent regions and lesion size increased. There was no neurological deterioration in patients harboring metastases in noneloquent areas.
authors.affiliation: Department of Neurosurgery, New York University Langone Medical Center, New York, New York 10016, USA.
authors.forename: Robert E
authors.initials: RE
authors.lastname: Elliott
authors.forename: Stephen
authors.initials: S
authors.lastname: Rush
authors.forename: Amr
authors.initials: A
authors.lastname: Morsi
authors.forename: Nisha
authors.initials: N
authors.lastname: Mehta
authors.forename: Jeri
authors.initials: J
authors.lastname: Spriet
authors.forename: Ashwatha
authors.initials: A
authors.lastname: Narayana
authors.forename: Bernadine
authors.initials: B
authors.lastname: Donahue
authors.forename: Erik C
authors.initials: EC
authors.lastname: Parker
authors.forename: John G
authors.initials: JG
authors.lastname: Golfinos
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001932:Brain Neoplasms / Q000473:pathology / Q000556:secondary* / Q000601:surgery*; D002423:Cause of Death; D002540:Cerebral Cortex / Q000473:pathology*; D018450:Disease Progression; D023381:Endpoint Determination; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D017567:Karnofsky Performance Status; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009422:Nervous System Diseases / Q000209:etiology* / Q000503:physiopathology*; D011183:Postoperative Complications / Q000503:physiopathology*; D016634:Radiosurgery / Q000009:adverse effects*; D012307:Risk Factors; D015173:Supratentorial Neoplasms / Q000556:secondary / Q000601:surgery; D016019:Survival Analysis; D016896:Treatment Outcome