Burr hole trephination for chronic subdural hematoma [Neurosurgery Wiki]

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====== Burr hole trephination for chronic subdural hematoma ======

{{rss>https://pubmed.ncbi.nlm.nih.gov/rss/search/1bEX5bJHyhtpg3E_LtMxRlB7qGbMzqvO1kj2rdJogsTz1vbYCH/?limit=15&utm_campaign=pubmed-2&fc=20221213100957}}
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[[Burr hole trephination]] for [[drainage]] of [[chronic subdural hematoma]]s are routine [[operative procedure]]s done by [[neurosurgery resident]]s. 

===== Burr hole trephination for chronic subdural hematoma with a closed drainage system =====

Double burr hole [[trepanation]] combined with a subperiostal passive closed-drainage system is a technically easy, highly effective, safe, and cost-efficient treatment strategy for symptomatic chronic subdural hematomas. The absence of a drain in direct contact with the [[hematoma capsule]] may moderate the risk of postoperative seizure and limit the secondary spread of infection to intracranial compartments
((Zumofen D, Regli L, Levivier M, Krayenbühl N. Chronic subdural hematomas
treated by burr hole trepanation and a subperiostal drainage system.
Neurosurgery. 2009 Jun;64(6):1116-21; discussion 1121-2. doi:
10.1227/01.NEU.0000345633.45961.BB. PubMed PMID: 19487891.
)).
----

The main aim of surgery should be a complete removal of the aggressive liquid. In case of many membranes that separate the hematoma into chambers like honeycomb an open procedure cannot be avoided. Nevertheless, the preferred operative therapy for most of CSDH is a burr hole craniostomy with a closed drainage system
((Santarius T, Kirkpatrick PJ, Ganesan D, Chia HL, Jalloh I, Smielewski P, Richards HK, Marcus H, Parker RA, Price SJ, Kirollos RW, Pickard JD, Hutchinson PJ (2009) Use of drains versus no drains after burr-hole evacuation of chronic subdural haematoma: a randomised controlled trial. Lancet 374:1067–1073))
((Weigel R, Schmiedek P, Krauss JK (2003) Outcome of contemporary surgery for chronic subdural haematoma: evidence based review. J Neurol Neurosurg Psychiatry 74:937–943)).

===== Surgical Technique =====

===== Surgical safety checklist =====

see [[Surgical safety checklist]].

===== Preoperative antibiotic prophylaxis =====

see [[Preoperative antibiotic prophylaxis]].

===== Skin Preparation =====

see [[Skin Preparation]].

===== Positioning =====

Preferably under general anesthesia the surgical approach should be over the thickest part of the hematoma and the patients positioned in a way that the burr hole comes to the highest point to avoid [[pneumocephalus]].

Therefore, the head is rotated and the ipsilateral shoulder is usually padded.

The [[supine position]] is used with the patient‘s head rotated for temporal access. Extremes of head rotation can obstruct the jugular venous drainage, and a shoulder roll can combat this problem or lateral positioning ([[park bench position]]).

{{::lateral_positioning.jpg?350|}}

===== Skin incision =====

Sites of predilection are frontal about 1 cm anterior to the [[coronal suture]] or parietal posterior to the [[parietal eminence]]. The area around [[Kocher’s point]] offers a safe entry without injury of branches of the [[middle meningeal artery]] or the [[motor strip]]. Additionally, the skin incision should be brought, if possible, into alignment with an eventual future skin flap for [[craniotomy]]. A curved flap avoids a burr hole position directly under the skin cut and a possible impaired wound-healing as a consequence. Further, the base of the C-shaped incision should be opposite of the planned direction of the drain tip. Obviously, a kinking of the drain is obviated
((Emich S, Dollenz M, Winkler PA. Burr hole is not burr hole: technical
considerations to the evacuation of chronic subdural hematomas. Acta Neurochir
(Wien). 2015 Jan 13. [Epub ahead of print] PubMed PMID: 25578345.
)).

===== Burr Holes =====

A performed [[burr hole]] with a diameter of 14 mm enables a sufficient angulation of the [[drain]] tip and allows an insertion of the drainage close to the [[calvaria]]. 
----
Diren and Ozdemir found that an increase in the width of [[burr hole]] [[craniotomy]] (BHC), especially the posterior BHC, contributed to the [[improvement]] in [[midline shift]]
((Diren F, Ozdemir O. The effectiveness of Burr-hole sizes on midline shift and hematoma thickness in the treatment of chronic subdural hematoma. World Neurosurg. 2023 Apr 20:S1878-8750(23)00546-6. doi: 10.1016/j.wneu.2023.04.062. Epub ahead of print. PMID: 37087033.)).


===== Dura mater opening =====

The [[dura mater]] is coagulated and cut in a stellate fashion. 

===== Technical issues =====

Under direct vision, the external membrane is perforated by the tips of the [[bipolar forceps]]. In general, there are the open or the closed ways of evacuation of the hematoma after the drain is inserted
((Tosaka M, Sakamoto K, Watanabe S, Yodonawa M, Kunimine H, Aishima K, Fujii T, Yoshimoto Y (2013) Critical classification of craniostomy for chronic subdural hematoma; safer technique for hematoma aspiration. Neurol Med Chir (Tokyo) 53:273–278))

The open variant should be chosen only if irrigation is desired: the dura and external membrane are opened widely so that the fluid of the hematoma and irrigation can drip out beside the drain during rinsing. Removal of the fluid enriched with inflammatory mediators is considered obviously as an advantage, although a remaining [[pneumocephalus]] is seen as an approved factor of recurrence
((Mori K, Maeda M (2001) Surgical treatment of chronic subdural hematoma in 500 consecutive cases: clinical characteristics, surgical outcome, complications, and recurrence rate. Neurol Med Chir (Tokyo) 41:371–381))
((Stanišić M, Hald J, Rasmussen IA, Pripp AH, Ivanović J, Kolstad F, Sundseth J, Züchner M, Lindegaard KF (2013) Volume and densities of chronic subdural haematoma obtained from CT imaging as predictors of postoperative recurrence: a prospective study of 107 operated patients. Acta Neurochir 155:323–333)).

In the closed way the aim is that no air enters the subdural space. Before the dural opening the drain is tunneled beneath the galea in the direction towards the middle of the base of the skin flap. A distance from the burr hole to the drain’s exit point of at least 5 cm prevents infection
((Berghauser Pont LM, Dammers R, Schouten JW, Lingsma HF, Dirven CM (2012) Clinical factors associated with outcome in chronic subdural haematoma: a retrospective cohort study of patients on preoperative corticosteroid therapy. Neurosurgery 70:873–880)).

Then the dura and external membrane are incised. This opening should have the same diameter as the drain to allow for a watertight and airtight drain introduction. The hematoma can therefore be evacuated only through the drain: the more fluid that is going to be collected, the more negative pressure that will be built up, which helps the brain to unfold again.

The dura is covered with a small piece of a [[gelatin sponge]] and the burr hole is filled and with bone chips collected at the beginning.

The last steps are to connect the drain to a closed collecting system and secure the connection and the exit point from the skin with [[suture]]s.
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Drain insertion after CSDH drainage is important, but position (subgaleal or subdural) and duration did not appear to influence recurrence rate or clinical outcomes. Similarly, drain location did not influence recurrence rate nor outcomes where both parietal and frontal burr holes were made. Further prospective cohort studies or randomized controlled trials could provide further clarification
((Glancz LJ, Poon MTC, Coulter IC, Hutchinson PJ, Kolias AG, Brennan PM. Does
Drain Position and Duration Influence Outcomes in Patients Undergoing Burr-Hole
Evacuation of Chronic Subdural Hematoma? Lessons from a UK Multicenter
Prospective Cohort Study. Neurosurgery. 2019 Oct 1;85(4):486-493. doi:
10.1093/neuros/nyy366. PubMed PMID: 30169738.
)).

===== Videos =====

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<html><iframe width="560" height="315" src="https://www.youtube.com/embed/6SndhEACTFo" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe></html>

===== Retrospective single-center cohort studies =====

In a [[retrospective]] single-center [[cohort study]], Zolnourian et al., from the [[University Hospital Southampton]] and Queen's Hospital, Barking, Havering, & Redbridge University Hospitals NHS Trust, [[London]], [[United Kingdom]], published in the [[Journal of Neurosurgery]], aimed to identify [[preoperative]] and [[perioperative]] factors that influence [[clinical outcome]]s, [[complication]]s, and hospital [[length of stay]] in [[adult]] patients undergoing [[burr hole]] [[drainage]] for [[chronic subdural hematoma]] (CSDH), in order to improve patient selection and surgical [[decision-making]].

They concluded that favorable short-term [[outcome]]s were primarily associated with nonmodifiable [[preoperative]] factors such as [[age]] under 80, preadmission [[independence]], higher [[Glasgow Coma Scale]] motor score, lower [[ASA]] grade, and fewer regular [[medication]]s. Surgical variables like laterality or the number of burr holes did not significantly impact [[outcome]]s. The use of [[subdural drain]]s was linked to better [[discharge]] outcomes but not to [[recurrence]] or [[complication]]s. These findings provide [[evidence]]-based criteria to guide surgical [[decision-making]] and patient [[counseling]].

((Zolnourian A, Manivannan S, Edwards B, Chua A, Arora M, Akhigbe T, Durnford A, Hempenstall J, Nader-Sepahi A, Bulters D, Sadek AR. [[Factor]]s affecting [[outcome]]s following [[burr hole]] [[drainage]] of [[chronic subdural hematoma]]: a single-center [[retrospective]] [[study]]. J Neurosurg. 2025 Feb 14;142(6):1606-1615. doi: 10.3171/2024.9.JNS24370. PMID: 39951707.))
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==== 📉 1. Redundancy Rebranded as Discovery ====  
The headline findings — that younger, fitter patients with fewer medications and lower ASA scores fare better — are hardly groundbreaking. These are well-known prognostic factors repeated in countless prior studies. Yet the authors present them as if freshly uncovered, bypassing the fact that any intern with access to the NICE guidelines could have written this paper in a call room.

==== 🧪 2. Retrospective Data Hoarding =====
A decade-long data sweep doesn’t automatically translate into depth. The absence of temporal stratification — especially in a period of evolving surgical and perioperative standards — renders the findings anachronistic. This is a textbook case of statistical inflation: more rows in a spreadsheet, but no added clinical clarity.

==== 🔩 3. Surgical Variables: All Bark, No Bite ==== 
The analysis confidently concludes that burr hole laterality and number don’t affect outcomes — something already well-established in the literature. Meanwhile, the discussion on subdural drain use is shallow at best, failing to differentiate between drain types, placement protocols, or duration. It’s a missed opportunity wrapped in procedural minimalism.

==== 💊 4. ASA Score Worship and Karnofsky Fetishism ====
The fixation on ASA grading and Karnofsky scores adds little to surgical decision-making. These scores are proxies, not causes. The authors seem content with tautological modeling: patients who are healthier do better. Who would’ve guessed?


==== 🏥 5. Outcomes at Discharge: The Mirage of Meaning ==== 
Evaluating outcomes **only at discharge** is misleading in a condition with delayed complications and high recurrence potential. Long-term cognitive, functional, and neurological data are conspicuously absent — yet the study draws bold conclusions as if the post-op day five [[GOS]] score is the final word in neurosurgical success.

==== 🗃️ 6. Editorial Bloat and Citation Padding ====
This paper is a classic of the genre: bloated in size, padded with references, yet starving in conceptual innovation. There’s no hypothesis refinement, no exploration of frailty, anticoagulation thresholds, or drainage protocols — just a dressed-up audit with statistical window dressing.

==== 🧠 Takeaway for the Neurosurgeon ====
The study confirms what seasoned neurosurgeons already know — that preoperative fitness matters, drains help, and surgical technique is less critical than patient selection. While it may aid in patient counseling, it contributes little to surgical strategy or innovation. Another brick in the wall of retrospective repetition.

===== References =====