title: Percutaneous Endoscopic Cervical Discectomy (PECD): An Analysis of Outcome, Causes of Reoperation.
abstract: OBJECTIVE
  Percutaneous endoscopic cervical discectomy (PECD) is regarded as an effective treatment modality in cervical disc herniation, including radicular pain and lateral location of disc herniation. This study aimed to evaluate the clinical and radiologic outcomes of PECD along with the causes of reoperation and the technique itself.
  
  
  METHODS
  Between January 2007 and November 2012, 101 patients underwent PECD at the Busan Wooridul Hospital. Three patients underwent a 2-level PECD. The mean follow-up period was 34 months (range, 18-72 months). The mean age was 46.1 years; the most common operation was at the C5-C6 level (n = 45), followed by C6-C7 (n = 35), C4-C5 (n = 16), and C3-C4 (n = 8). The clinical outcomes were evaluated via the visual analog scale of the neck and arm according to the Neck Disability Index and the modified Macnab criteria. Among 101 patients, 12 underwent an additional operation at the index level. Five patients had aggravated stenosis by disc height narrowing, 4 had recurred disc, 2 had remained disc, and 1 had sustained symptoms.
  
  
  RESULTS
  After PECD, there was a significant improvement in the visual analog scale and Neck Disability Index scores (P < 0.001). According to the modified Macnab criteria, excellent concordance was achieved in 65 patients, good in 22, fair in 2, and poor in 12. The reoperation performed on 12 patients improved their clinical outcomes. The mean duration was 4.8 months (2 days to 18 months) until reoperation. There were 3 PECD revisions, 3 artificial disc replacements, 2 corpectomies, 2 anterior cervical discectomies and fusion with cages, and 2 transfers to another hospital. The common feature was older age (P = 0.016) and male sex (P = 0.031). Preoperative radiologic findings were characterized by the foraminal disc (P = 0.04), disc degeneration at the index level (P = 0.05), combined bony spur (P = 0.001), concomitant adjacent level degeneration (P = 0.019), cervical kyphosis (P = 0.015), and segmental angle deterioration after PECD (P = 0.038). No statistical correlation was seen between the operation level and herniation size (P > 0.05).
  
  
  CONCLUSIONS
  In total, 87% patients showed successful clinical outcome. Poor and fair outcomes at initial PECD were overcome by revision surgery, which improved outcomes. Although PECD is a promising minimally invasive procedure for cervical disc treatment, the indications for PECD should be considered carefully.
authors.affiliation: Department of Neurosurgery, Spine Health Wooridul Hospital, Busan, Korea. Electronic address: bstonefive@naver.com.
authors.forename: Hyeong Seok
authors.initials: HS
authors.lastname: Oh
authors.affiliation: Department of Neurosurgery, Spine Health Wooridul Hospital, Busan, Korea.
authors.forename: Byeong-Wook
authors.initials: BW
authors.lastname: Hwang
authors.affiliation: Department of Neurosurgery, Spine Health Wooridul Hospital, Busan, Korea.
authors.forename: Sang-Joon
authors.initials: SJ
authors.lastname: Park
authors.affiliation: Department of Neurosurgery, Spine Health Wooridul Hospital, Busan, Korea.
authors.forename: Chang-Sheng
authors.initials: CS
authors.lastname: Hsieh
authors.affiliation: Department of Neurosurgery, Spine Health Wooridul Hospital Gangnam, Seoul, Korea.
authors.forename: Sang-Ho
authors.initials: SH
authors.lastname: Lee
mesh_terms: D000328:Adult; D000368:Aged; D002574:Cervical Vertebrae / Q000601:surgery*; D017587:Diskectomy, Percutaneous / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D007405:Intervertebral Disc Displacement / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011859:Radiography; D012086:Reoperation / Q000706:statistics & numerical data; D012189:Retrospective Studies; D016896:Treatment Outcome
keywords: Cervical disc herniation; Minimally invasive spine surgery; Percutaneous endoscopic cervical discectomy