title: The 6 thalamic regions: surgical approaches to thalamic cavernous malformations, operative results, and clinical outcomes.
abstract: OBJECTIVE
  The ideal surgical approach to thalamic cavernous malformations (CMs) varies according to their location within the thalamus. To standardize surgical approaches, the authors have divided the thalamus into 6 different regions and matched them with the corresponding surgical approach.
  
  
  METHODS
  The regions were defined as Region 1 (anteroinferior), Region 2 (medial), Region 3 (lateral), Region 4 (posterosuperior), Region 5 (lateral posteroinferior), and Region 6 (medial posteroinferior). The senior author's surgical experience with 46 thalamic CMs was reviewed according to this classification. An orbitozygomatic approach was used for Region 1; anterior ipsilateral transcallosal for Region 2; anterior contralateral transcallosal for Region 3; posterior transcallosal for Region 4; parietooccipital transventricularfor Region 5; and supracerebellar-infratentorial for Region 6.
  
  
  RESULTS
  Region 3 was the most common location (17 [37%]). There were 5 CMs in Region 1 (11%), 9 in Region 2 (20%), 17 in Region 3 (37%), 3 in Region 4 (6%), 4 in Region 5 (9%), and 8 in Region 6 (17%). Complete resection was achieved in all patients except for 2, who required a second-stage operation. The mean follow-up period was 1.7 years (range 6 months-9 years). At the last clinical follow-up, 40 patients (87%) had an excellent or good outcome (modified Rankin Scale [mRS] scores 0-2) and 6 (13%) had poor outcome (mRS scores 3-4). Relative to their preoperative condition, 42 patients (91%) were unchanged or improved, and 4 (9%) were worse.
  
  
  CONCLUSIONS
  The authors have presented the largest series reported to date of surgically treated thalamic CMs, achieving excellent results using this methodology. In the authors' experience, conceptually dividing the thalamus into 6 different regions aids in the selection of the ideal surgical approach fora specific region.
authors.affiliation: Division of Neurological Surgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona.
authors.forename: Leonardo
authors.initials: L
authors.lastname: Rangel-Castilla
authors.affiliation: Division of Neurological Surgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona.
authors.forename: Robert F
authors.initials: RF
authors.lastname: Spetzler
mesh_terms: D000293:Adolescent; D000328:Adult; D001932:Brain Neoplasms / Q000473:pathology / Q000601:surgery*; D002648:Child; D005260:Female; D020786:Hemangioma, Cavernous, Central Nervous System / Q000473:pathology / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000379:methods*; D013788:Thalamus / Q000473:pathology / Q000601:surgery*; D016896:Treatment Outcome; D055815:Young Adult
keywords: ACT = anterior contralateral interhemispheric transcallosal; AIT = anterior ipsilateral interhemispheric transcallosal; CM = cavernous malformation; DVA= developmental venous anomaly; GTR = gross-total resection; OZ = orbitozygomatic; PIT = posterior interhemispheric transcallosal; POT = parietooccipital transventricular; SCIT = suboccipital supracerebellar infratentorial; cavernous malformation; mRS = modified Rankin Scale; surgical approaches; thalamic regions; thalamus; vascular disorders