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

Objective: Risk factors for hypermagnesemia due to magnesium oxide (MgO) include advanced age, decreased renal function, and long-term administration; however, no study has evaluated patients that present all of these factors. This study was aimed to evaluate the safety of long-term MgO administration in elderly patients with impaired renal function.Methods: We investigated changes in serum Mg in patients aged 65 years or older, who had been taking oral MgO and presenting a glomerular filtration rate (eGFR) ＜60 mL/min/1.73 m2 for 6 months or longer.Results: Thirty patients were surveyed. Their median age was 81 years (range, 68-92). No significant change in patient background was observed before and after initiating MgO administration, with no change in serum Mg detected. Furthermore, the oral dose of MgO was divided into groups taking ＜1,000 mg and ≥ 1,000 mg; no change in serum Mg was observed in either group. Based on renal function, the analysis was divided into a mildly decreased group (60＞ eGFR ≥ 45) and a moderately to severely decreased group (45＞ eGFR ≥ 15), and no change in serum Mg was observed in either group.Conclusions: We targeted elderly patients with renal dysfunction who were taking long-term MgO, a known risk factor for hypermagnesemia, indicating that MgO can be safely continued.