Prospective study of postoperative lumbar epidural hematoma: incidence and risk factors.

STUDY DESIGN: Prospective clinical series. OBJECTIVE: To determine the incidence, volume, and extent of postoperative epidural hematoma resulting in thecal sac compression, and to identify risk factors correlated with measured hematoma volumes. SUMMARY OF BACKGROUND DATA: Risk factors for postoperative hematoma development have been retrospectively determined in small populations of symptomatic patients. A prospective study of hematoma characteristics and associated risk factors in a consecutive series of patients could significantly enhance our understanding of postoperative hematoma. METHODS: Preoperative magnetic resonance imaging and clinical data on 13 pre- and intraoperative risk factors were prospectively collected on 50 consecutive patients undergoing lumbar decompression surgery with or without fusion. Postoperative magnetic resonance imagings were performed within 2 to 5 days of surgery. Thecal sac cross-sectional area was calculated at each disc space. Relative thecal sac compression due to hematoma was calculated at all levels where postoperative cross-sectional area was smaller than preoperative. Hematoma volumes were calculated. Multivariate analysis identified risk factors associated with postoperative hematoma volume. RESULTS: After decompression, 58% of patients developed epidural hematoma of sufficient magnitude to compress the thecal sac beyond its preoperative state at one or more levels. None developed new postoperative neurologic deficits. A mean of 1.4 levels were decompressed. Hematoma extended over a mean of 1.9 levels. Maximal thecal sac compression due to hematoma occurred at an adjacent, nondecompressed level in 28% of patients. Multivariate analysis found age greater than 60, multilevel procedures, and preoperative international normalized ratio to be associated with larger hematoma volumes. CONCLUSION: Lumbar decompression surgery results in a 58% incidence of asymptomatic compressive postoperative epidural hematoma. Adjacent level compression by hematoma occurs in 28% of patients. Advanced age, multilevel procedures, and international normalized ratio are independently associated with postoperative hematoma volume.

Postoperative lumbar epidural hematoma: does size really matter?

STUDY DESIGN: Prospective clinical series with comparison to retrospectively collected data. OBJECTIVE: To compare direct measures of postoperative hematoma volume against a new measure of hematoma effect on the thecal sac: the critical ratio. SUMMARY OF BACKGROUND DATA: Asymptomatic epidural hematoma is common after lumbar surgery. Symptomatic patients demonstrate a typical progression from sharp peri-incisional pain to bilateral neurologic deficits. Little is known about what differentiates symptomatic and asymptomatic patients. Magnetic resonance imaging (MRI) measures of hematoma size or mass effect may correlate with postoperative symptoms. METHODS: The study population consisted of 3 patient groups evaluated by MRI 2 to 5 days after lumbar decompression with or without fusion. Fifty-seven consecutive prospectively enrolled patients comprised the asymptomatic group. No patient developed severe postoperative pain or neurologic deficit. Search of our institutional database identified 4978 surgical patients within the last 24 months. Seventeen developed new postoperative symptoms. The painful group included 12 patients with severe peri-incisional pain without neurologic deficit. The cauda equina (CE) group included 5 patients with postoperative CE syndrome. Digital imaging software was used to calculate thecal sac cross sectional area on pre- and postoperative MRI at each level, hematoma volume, volume per level decompressed, and critical ratio for each patient. Critical ratio was defined as the smallest ratio of postoperative to preoperative cross sectional area within the lumbar spine. RESULTS.: The critical ratio was the only measure found to differ significantly (P < 0.05) among all 3 groups. Mean critical ratios were asymptomatic (0.8), painful (0.5), and CE (0.2). CONCLUSION: The critical ratio correlates more closely with the presence or absence of postoperative symptoms than measures of hematoma volume, and is consistent with the clinical expectation that greater thecal sac compression may result in more severe symptoms. Few guidelines exist for postoperative lumbar MRI interpretation. The critical ratio is an important contribution.

Acute mortality and complications of cervical spine injuries in the elderly at a single tertiary care center.

STUDY DESIGN: Retrospective database review of all traumatic cervical spine injuries at a single tertiary care center. OBJECTIVE: To determine the acute survival of patients aged 65 and over with a variety of cervical spine injuries, regardless of operative or conservative treatment. SUMMARY OF BACKGROUND DATA: Elderly patients with cervical spine injuries have historically suffered from high mortality rates. More recent literature has demonstrated improved outcomes among operatively treated elderly, but has suggested that the nonoperative treatment of cervical injuries in this population may itself contribute to increased mortality rates. METHODS: One thousand seventy-three consecutive patients were identified and initial hospitalization records reviewed. Ninety-four patients were excluded for incomplete data. The remaining 979 patients were divided by age into young and elderly groups. Sex distribution, mechanism, injury type, comorbidities, and mortality and complication rates were compared. Elderly patients were further divided into operative and nonoperative groups and acute outcomes were compared. RESULTS: The overall acute mortality rate for all patients with cervical spine injuries was 5.92%. Eighty-six percent of all patients 65 and over survived, as did 96.1% of younger patients. Seventy-three percent of elderly patients with complete injuries survived, as did 80% of those with incomplete injuries, and 95.6% of intact elderly. Acute mortality rates were statistically comparable in both the operatively and nonoperatively treated groups of elderly. CONCLUSIONS: In this large comprehensive series of elderly patients with cervical spine injuries, statistically comparable survival rates were achieved in both operatively treated and nonoperatively treated patient populations. This finding challenges the conclusion that the nonoperative treatment of the elderly necessarily results in increased acute mortality.