Chronic Subdural Hematoma: Pitfalls to Avoid for Better Outcome

Introduction: Chronic subdural hematoma is one of the commonest intracranial haemorrhages that affect elderly. Headache and focal neurological deficits are among the commonest presentations. It carries excellent prognosis especially when evacuated probably on right timing. Recurrence rate ranging from 8% 37% in literatures, we will highlight tricks during peri-operative period to have better outcome and decrease recurrence. Patients and methods: We operated 45 cases of chronic subdural hematoma in Cairo university emergencyhospital, during the period from November 2016 to December 2017; CT brain was done for all cases; clinical data were reported; burr hole evacuation was the standard technique. Suction drain with mild suction pressure was applied and hospital stay was 3 4 days after surgery. Patients were followed up to three months. Results: Forty-five patients were operated with 27 cases (60%) having their ages between 5 and 7 decades. Among Twenty-nine males and 16 females, eleven patients (25%) were confused; headache was observed in 12 patients, weakness in 31 cases (69%), dysphasia in two cases and two patients were on renal dialysis. Hypertension was associated as a comorbidity in 18 patients, diabetes mellitus in 11 patients, and smoking in 11 patients. Forty-two patients were discharged home within 3 4 days; two cases developed small-sized intra-cerebral hematoma, one case of wound infection, and excellent outcome for all cases on three months follow up visit. Conclusions: Chronic subdural hematoma is one of the commonest intra-cranial haemorrhages in elderly with excellent outcome if managed meticulously in right timing. Good control of co-morbidities, insuring slow clearing of hematoma fluid and staged closure technique are factors linked with better outcome. But larger studies are needed.


Introduction
Pachymeningitis haemorrhagica interna, a term was used by Virchow to name chronic subdural hematoma (CSDH) during the eighteen century (1857).
Trauma to bridging veins was later postulated by trotter and changes its name to subdural haemorrhagic cyst [1].
It is one of the commonest intracranial pathologies that give excellent outcomes if managed probably and in the right timing. Longer life expectancy in developing countries had increased the incidence of CSDH [2] [3] [4] [5].
Old people are more exposed to develop CSDH especially after minor trauma due to brain atrophy that decreases the space between the brain and skull from 6% to 11% of the intracranial space, leading to stretching of aging fragile cortical veins that can be easily torn with minor trauma [6] [7].
Although trauma is an important factor to develop CSDH; however direct head trauma is absent in up to 30% -50% of the patients. Fall without hitting the head to the ground was reported in almost half of CSDH patients [8] [9].
Other risk factors may include bleeding tendency, epilepsy, alcoholism and cases that may develop low intracranial pressure in conditions like dehydration and renal dialysis [10].
The collected blood will be covered by thin layer of fibrin and fibroblasts forming hematoma membrane on the fourth day up to two weeks. Phagocytes lead to haematoma liquefaction. New fragile vessel formed in the capsule [11].
The osmotic theory claims that the difference between hematoma contents with higher proteins facilitating fluid transfer through the semipermeable membrane from the nearby vessels [12]. It was denied by Wier et al. who proved that hematoma fluid, blood and cerebrospinal fluid CSF have the same osmolality [13].
Recurrent bleeding from abnormally dilated blood vessels in CSDH capsule is nowadays more accepted theory especially with concurrent use of anticoagulation [14].
Ito et al. demonstrated that there is fresh bleeding in CSDH evacuated fluid reaching from 2% -28% of cases that were injected 51 cr-labled RBCs intravenously 6 -24 hours before evacuation [15].
We will discuss our experience in CSDH cases with highlight on pitfalls to avoid recurrence.

Methods
During the period from November 2016 to December 2017 we operated 45 cases of CSDH in emergency neurosurgery unit, Cairo university hospitals, Egypt.
Computerized topography was done for all cases, and after confirming the diagnosis and indication for surgery, preparation and shifting to operating room was done ( Figure 1). Our department ethical committee approval was taken for our study.

Pre-Operative Tricks
Whenever possible, pre-operative assessment and control of associated co-morbidity are important for better outcome especially coagulopathy, renal impairment or diabetes mellitus.

Operative Tricks
− We usually do our operation under general anaesthesia expect if associated co-morbidity that carries high mortality risk, so we prefer local anaesthesia and sedation only. − Staged closure technique: closure in layers without covering of the dural opening to facilitate any fluid in subdural space to be drained. We start closing posterior wound first and ensuring that wash fluid between sutures to come through the drain and anterior wound clearly then closure of anterior wound is done. This step helps to avoid post-operative peumocephaly.
− Mild suction power is applied, and suction drain is unlocked after full recovery from anaesthesia.
− Prophylactic anticonvulsants were given for one month even if seizures were not the presenting symptom. − Head elevation up to 30 degrees may be applied.

Results
We operated forty-five cases of CSDH including 29 males (65%) and 16 females (35%), twenty-seven cases (60%) with ages lies in 5 th to 7 th decade, we have three cases over 80 years.
Headache was the presenting symptom in 12 cases, weakness was clinically observed in 31 patients (69%) and it was almost equally affecting both sides of the body. Two cases were dysphasic, and one patient was on renal dialysis. Regarding co-morbidity 18 (40%) patients were hypertensive, 11 patients were diabetics, five hepatic patients, 11 cases were smokers, two cardiac, two renal patients (one presenting during dialysis session). And three cases were on anticoagulants ( Figure 3).
Midline shift was 1 -2 cm in twenty-nine cases (65%), more than 3 cm in one case and the rest of cases didn't show midline shift or it was less than 1 cm.
Tirty three patients (74%) are with hematoma thickness 3 -4 cm, eleven patients (24%) with hematoma thickness 2 cm and one case with 5 cm hematoma thickness ( Figure 5).     One patient developed wound infection which also was treated with antibiotic course and tight DM control and patient was discharged after one week.

None of our cases develop tension pneumocephaly or seizures post-operative
During the first month follow up visit; six cases develop re-appearance of symptoms (four cases with weakness and two cases of headache) and by repeating CT scan, re-collection and second exploration were done.
Follow up visit after three months was done. Excellent recovery was achieved for all cases including the recollected cases. And the patients presenting with weakness resumed normal motor power.

Discussion
Chronic subdural hematoma is one of commonest types of intracranial haemor- The CSDH thickness in pre-operative CT scan may give an impression about outcome prediction. the more the thickness, the more expected bad elasticity of the brain especially in old age and poor expansion with higher possibility of recurrence and pneumocephaly to develop [2] [18] [40].
Four of our recurrent cases were with hematoma thickness from 3 to 4 cm with age in 5 th and 6 th decades which is like what was expected by other authors.
We don't have post-operative tension peumocephaly in our cases and this may be due to the closure technique mentioned before.
Morbidity and mortality differ significantly in literature in cases of CSDH after surgery but in general it may reach 16% and 6.5% respectively [41]. In our study six patients developed recollection (13%) and were re-operated, we had no mortality and all neurological deficits resolved on the three months follow-up visit.
Our study has some limitation include small study number and focusing only on one surgical technique (burr hole evacuation) but further studies should consider collaboration with other centres performing different modalities for CSDH management.

Conclusion
Chronic subdural hematoma is one of the commonest intracranial haemorrhages in elderly that carries excellent outcome after evacuation. Peri-operative good control of co-morbidities, insuring slow clearing of hematoma fluid and staged closure technique are factors linked with better outcome. But larger studies are needed.