A study published today in the Journal of Neurosurgery by a neurosurgical team from Allegheny General Hospital (AGH) in Pittsburgh reveals that a fairly common disease in the elderly – called chronic subdural hematoma – has a much higher long- term mortality rate than previously thought after patients have undergone what is considered routine treatment.
The study – Chronic subdural hematoma in the elderly: not a benign disease – reviews the cases of 209 patients with chronic subdural hematoma (CSDH) who were treated at AGH between September 2000 and February 2008.
Chronic subdural hematoma is an old clot of blood on the surface of the brain beneath its outer covering. The condition is more common in the elderly because of normal brain shrinkage that occurs with aging. This shrinkage stretches and weakens the bridging veins, so that even minor head trauma can cause tearing of blood vessels over the brain surface, resulting in a slow accumulation of blood over several days to weeks. Left untreated, the CSDH can cause severe physical, emotional, and cognitive impairments.
“CSDH is a frequently encountered problem in neurosurgical practice and the perception is that it is a benign disease, with easy-to-treat lesions. As such, the majority of neurosurgical literature has been limited to short-term outcome analysis, focusing primarily on types of surgical interventions, the effect of anticoagulants, and whether drains should be left in place. We believe our research is the first long-term analysis of CSDH in an elderly-only population,” said Matthew Quigley, MD., the paper’s senior author and a neurosurgeon at AGH.
In addition to Dr. Quigley, other authors of the paper include AGH neurosurgeons Lucas Bernardes Miranda, MD, Ernest Braxton, MD, and Joseph Hobbs, MD. An accompanying editorial in the Journal is authored by Kim J. Burchiel, MD, Department of Neurosurgery, Oregon Health and Science University, Portland, Oregon. The article and editorial will be posted online (September 24, 11 am EST) at: http://thejns.org/toc/jns/forthcoming.
Among patients enrolled in the study, the primary surgical interventions performed were bur holes (21 patients), twist-drill closed system drainage (44 patients) and craniotomies (72 patients). An additional 72 patients were simply observed. Thirty five patients (16.7 %) died in the hospital, 130 were discharged to rehabilitation or a skilled care facility and 44 returned home. Long-term follow-up extended to a maximum of 8.3 years (mean 1.45 years).
The authors found that survival was not related to the type of surgical intervention or to whether surgery was performed. Furthermore, the type of intervention, size of the CSDH, amount of shift, the presence of bilateral CSDHs, and anticoagulant use had no significant impact on the short- or long-term mortality. Only age and discharge to home were related to survival.
“While the 16.7 percent hospital mortality rate was just slightly higher than in other CSDH studies, what stood out was that this rate climbed to 26.3 percent and 32 percent respectively, at 6-month and 1-year follow-up, after what was considered successful treatment,” said Dr. Quigley.
“Another surprising finding was that the hazard ratios derived from data showed that younger patients (age range 60–69 years) had the highest mortality rate, with the risk progressively diminishing in each successive decade to the tenth,” added Dr. Burchiel.
The authors liken the continued increased mortality following apparently successful treatment of CSDH to the similar and widely reported phenomenon in patients who have undergone successful surgery for hip fracture.
In light of the hazard ratio age findings, the authors surmise that if CSDH is indeed a “marker” of underlying disease, the younger one experiences this disease, the more compromised one’s health will be relative to others in that age group.
“As with hip fracture, we assume that CSDH unmasks underlying medical conditions and exacerbates them. Although additional studies are required, given our long-term outcome findings, this disease should be reassessed by physicians and family members from a “benign” disease to one with potentially grave patient consequences,” concluded Dr. Quigley.
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