title: Surgical outcome and prognostic factors of anterior decompression and fusion for cervical compressive myelopathy due to ossification of the posterior longitudinal ligament.
abstract: BACKGROUND
  Anterior decompression and fusion (ADF) for ossification of the posterior longitudinal ligament (OPLL) is technically demanding and associated with complications. Although various factors affecting clinical outcome have been investigated in posterior decompression, prognostic factors of ADF remain unclear.
  
  
  OBJECTIVE
  The purpose of the study was to identify surgical outcome and prognostic factors of ADF for cervical myelopathy due to OPLL.
  
  
  METHODS
  This was a retrospective case study.
  
  
  METHODS
  Between 2005 and 2012, 913 patients underwent decompression surgery for cervical OPLL at our institution. Among them, 131 who underwent ADF and 221 who underwent laminoplasty were enrolled. Inclusion criteria were (1) diagnosis of OPLL; (2) cervical compressive myelopathy; and (3) no trauma, infection, tumor, or previous surgery. We excluded 60 patients with ADF and 157 patients with laminoplasty owing to inadequate follow-up or absence of preoperative myelopathy. Finally, 71 patients with ADF and 64 patients with laminoplasty were enrolled in this study (mean follow-up, 48 vs 41 months).
  
  
  METHODS
  Neurologic assessment was conducted using the Japanese Orthopedic Association (JOA) scoring system for cervical myelopathy. Rate of neurologic improvement was calculated by comparing preoperative and postoperative JOA scores.
  
  
  METHODS
  We investigated the effects of such variables as age, gender, body mass index (BMI), presence of diabetes mellitus (DM), smoking history, type of OPLL, shape of the ossified lesion, occupying ratio of OPLL, presence of intramedullary increased signal intensity (ISI) on magnetic resonance imaging (MRI), and sagittal alignment of the cervical spine on surgical outcome. Severity of ISI was classified into three groups based on T2-weighted sagittal MRI as follows: Grade 0, none; Grade 1, ISI limited to one disc level; or Grade 2, ISI beyond one disc level. This work was supported by the 2013 Korea Health Technology R&D Project of the Ministry of Health and Welfare of the Republic of Korea (A120254).
  
  
  RESULTS
  In patients with an occupying ratio ≥60% or with presence of ISI on MRI, ADF yielded better surgical outcome than laminoplasty. A higher ISI grade (B=-28.5, p=.000) and a higher occupying ratio (B=0.88, p=.04) were significantly associated with a lower recovery rate (R=0.56, p=.006). Older age also was associated with a lower recovery rate. Gender, BMI, presence of DM, smoking history, type of OPLL, shape of the ossified lesion, and cervical alignment were not associated with recovery rate.
  
  
  CONCLUSIONS
  Anterior decompression and fusion has favorable outcome in patients with an occupying ratio ≥60% or with presence of ISI on MRI. Presence of higher ISI grade, higher occupying ratio, and older age were associated with a poor long-term surgical prognosis. Therefore, evaluating ISI and occupying ratio on preoperative MRI is important for selecting the appropriate surgical approach and for predicting clinical outcome after surgery for cervical compressive myelopathy due to OPLL.
authors: Department of Neurosurgery, Spine and Spinal Cord Institute, Yonsei University College of Medicine, Severance Hospital, 134 Shinchon-dong Seodaemun-gu, Seoul 120-752, Korea.
authors: Byeongwoo
authors: B
authors: Kim
authors: Department of Neurosurgery, Spine and Spinal Cord Institute, Yonsei University College of Medicine, Severance Hospital, 134 Shinchon-dong Seodaemun-gu, Seoul 120-752, Korea.
authors: Do Heum
authors: DH
authors: Yoon
authors: Department of Neurosurgery, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, 25-2, Sungkyunkwan-ro, Seoul, Seoul 110-745, Korea.
authors: Hyun Chul
authors: HC
authors: Shin
authors: Department of Neurosurgery, Spine and Spinal Cord Institute, Yonsei University College of Medicine, Severance Hospital, 134 Shinchon-dong Seodaemun-gu, Seoul 120-752, Korea.
authors: Keung Nyun
authors: KN
authors: Kim
authors: Department of Neurosurgery, Spine and Spinal Cord Institute, Yonsei University College of Medicine, Severance Hospital, 134 Shinchon-dong Seodaemun-gu, Seoul 120-752, Korea.
authors: Seong
authors: S
authors: Yi
authors: Department of Neurosurgery, Spine and Spinal Cord Institute, Yonsei University College of Medicine, Severance Hospital, 134 Shinchon-dong Seodaemun-gu, Seoul 120-752, Korea.
authors: Dong Ah
authors: DA
authors: Shin
authors: Department of Neurosurgery, Spine and Spinal Cord Institute, Yonsei University College of Medicine, Severance Hospital, 134 Shinchon-dong Seodaemun-gu, Seoul 120-752, Korea; Department of Neurosurgery, Brain Korea 21 PLUS Project for Medical Science, College of Medicine, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, Seoul 120-749, Korea. Electronic address: ayoon@yuhs.ac.
authors: Yoon
authors: Y
authors: Ha
mesh_terms: D000328:Adult; D000368:Aged; D002574:Cervical Vertebrae / Q000601:surgery*; D019299:Decompression, Surgical / Q000009:adverse effects*; D005260:Female; D006801:Humans; D065406:Laminoplasty / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D017887:Ossification of Posterior Longitudinal Ligament / Q000601:surgery*; D011379:Prognosis; D012189:Retrospective Studies; D013118:Spinal Cord Diseases / Q000601:surgery*; D013123:Spinal Fusion / Q000009:adverse effects*; D016896:Treatment Outcome
keywords: Anterior decompression and fusion; Cervical ossification of the posterior longitudinal ligament; Compressive myelopathy; Laminoplasty; Magnetic resonance imaging; Prognostic factors