STUDY DESIGN: A retrospective study. PURPOSE: Our objectives were to determine the association between the pathological changes of disc herniation and the interval between primary and revision surgeries and to investigate the frequency and site of the dural laceration in the primary and revision surgeries. OVERVIEW OF LITERATURE: Among 382 patients who underwent microsurgical lumbar discectomy, we investigated 29 who underwent revision surgery to analyze recurrent herniation pathologies and complications to determine the manner in which lumbar disc herniation can be more efficiently managed. METHODS: Of 29 patients, 22 had recurrent disc herniation at the same level and site. The pathological changes associated with compression factors were classified into the following two types depending on intraoperative findings: (1) true recurrence and (2) minor recurrence with peridural fibrosis (>4 mm thickness). The sites of dural laceration were examined using video footage and operative records. RESULTS: The pathological findings and days between the primary and revision surgeries showed no statistical difference (p=0.14). Analysis of multiple factors, revealed no significant difference between the primary and revision surgery groups with regard to hospital days (p=0.23), blood loss (p=0.99), and operative time (p=0.67). Dural lacerations obviously increased in the revision surgery group (1.3% vs. 16.7%, p < 0.01) and were mainly located near the herniated disc in the primary surgery group and near the root shoulder in the revision surgery group, where severe fibrosis and adhesion were confirmed. To avoid dural laceration during revision surgery, meticulous decompressive manipulation must be performed around the root sleeve. CONCLUSIONS: We recommend that meticulous epidural dissection around the scar formation must be performed during revision surgery to avoid complications.
Cicatrix ; Diskectomy ; Fibrosis ; Humans ; Intervertebral Disc Displacement ; Lacerations ; Operative Time ; Pathologic Processes ; Pathology ; Recurrence ; Reoperation ; Retrospective Studies ; Shoulder

STUDY DESIGN: Retrospective case series. PURPOSE: To elucidate the impact of postoperative occiput-C2 (O-C2) angle change on subaxial cervical alignment. OVERVIEW OF LITERATURE: In the case of occipito-upper cervical fixation surgery, it is recommended that the O-C2 angle should be set larger than the preoperative value postoperatively. METHODS: The present study included 17 patients who underwent occipito-upper cervical spine (above C4) posterior fixation surgery for atlantoaxial subluxation of various etiologies. Plain lateral cervical radiographs in a neutral position at standing were obtained and the O-C2 angle and subaxial lordosis angle (the angle between the endplates of the lowest instrumented vertebra (LIV) and C7 vertebrae) were measured preoperatively and postoperatively soon after surgery and ambulation and at the final follow-up visit. RESULTS: There was a significant negative correlation between the average postoperative alteration of O-C2 angle (DO-C2) and the average postoperative alteration of subaxial lordosis angle (Dsubaxial lordosis angle) (r=-0.47, p=0.03). CONCLUSIONS: There was a negative correlation between DO-C2 and Dsubaxial lordosis angles. This suggests that decrease of mid-to lower-cervical lordosis acts as a compensatory mechanism for lordotic correction between the occiput and C2. In occipito-cervical fusion surgery, care must be taken to avoid excessive O-C2 angle correction because it might induce mid-to-lower cervical compensatory decrease of lordosis.
Animals ; Follow-Up Studies ; Humans ; Lordosis* ; Occipital Bone ; Retrospective Studies ; Spinal Curvatures ; Spinal Fusion ; Spine ; Walking