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CC BY-NC-ND 4.0 · Asian J Neurosurg
DOI: 10.1055/s-0045-1809919
Case Report

Ultrasound-Guided Scalp Block for Chronic Subdural Hematoma Evacuation—A Case Series and Review of Literature

Ashwini Reddy 
1   Department of Anesthesia and Intensive Care, Postgraduate Institute of Medical Education and Research, Chandigarh, India
,
Kajal Jain
1   Department of Anesthesia and Intensive Care, Postgraduate Institute of Medical Education and Research, Chandigarh, India
,
Amiya Kumar Barik 
1   Department of Anesthesia and Intensive Care, Postgraduate Institute of Medical Education and Research, Chandigarh, India
,
Kirandeep Kaur
1   Department of Anesthesia and Intensive Care, Postgraduate Institute of Medical Education and Research, Chandigarh, India
› Author Affiliations

Funding None.
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Abstract

Burr hole craniotomy for the evacuation of subdural hematoma (SDH) can be performed under general anesthesia, surgical site local anesthesia, or scalp block. The prevalence of SDH is higher in the geriatric age group who often suffers from multiple comorbidities. The use of general anesthesia with polypharmacy and airway manipulation may adversely affect the systemic physiology in these patients with substantially decreased reserve. Relief of pain is often inadequate with surgical site local anesthesia leading to tachycardia, hypertension, adverse cardiovascular events, and poor patient satisfaction. Scalp block provides dense prolonged blockade of select target nerves and avoids sedation facilitating early recovery and discharge. However, it is associated with multiple complications including intraneural/arterial injection, and local anesthetic systemic toxicity. The use of ultrasound has ushered in a new era in the field of regional anesthesia; however, the use of ultrasound-guided scalp blocks is not routinely practiced. The use of ultrasound has an opioid-sparing effect and avoids complications like facial nerve palsy and hematoma. We report the first case series of successful ultrasound-guided scalp blocks for the evacuation of chronic SDH.


 

Keywords

burr hole - geriatric patients - ultrasound - scalp block - subdural hematoma

Introduction

Minimal craniotomy (burr hole) and evacuation of bleed are the treatment of choice in symptomatic cases of chronic subdural hematoma (SDH).[1] The choice of anesthesia depends on the patient's neurologic condition (Glasgow coma scale [GCS]), the size and location of the SDH, and the surgical approach. Agitated patients with poor GCS and the presence of large bilateral/septate SDH who might have to undergo open craniotomy and evacuation will most likely require general anesthesia (GA) for the smooth conduct of surgery. GA involves airway manipulation, polypharmacy, and prolonged hospitalization. Local anesthetic (LA) administration at the surgical site is commonly done, but its effect is inadequate, transient, and short-lived. A scalp block with focused anatomically directed injections of LA targeted to the particular nerves innervating the scalp provides longer-lasting dense analgesia.[2] [3] However, variations in the origin and course of the nerves lead to complications like an inadequate blockade, neural injury, use of large volumes of LA, and inadvertent intraarterial injection.[4] Ultrasonography has led to radical advances in regional anesthesia and can be used to avoid these complications.[5]

A review of the literature (PubMed, Medline, Embase, and Science Direct) revealed isolated case reports of awake craniotomy performed under ultrasound-guided scalp block along with sedation. We report the first case series of burr hole evacuation of SDH performed under successful ultrasound-guided scalp block and monitored anesthesia care.


 

Case Report

We included five patients with a history of trivial head injury ([Table 1]), three of whom were diagnosed with unilateral frontotemporoparietal SDH, and two patients with bilateral SDH. Two of these patients presented with altered behavior, nausea, and vomiting, while three of them presented with a persistent headache and dizziness. After standard clinical and radiological assessment along with required investigations, all the patients were counseled regarding the administration of scalp block and the need for cooperation and communication during the surgical procedure and written informed consent was taken.

Adequate fasting was confirmed before wheeling inside the operation room, standard monitoring was instituted, and oxygen was supplemented with a nasal cannula (4 L/min). The scalp block was performed using ultrasound guidance as reported by Zetlaoui et al.[3] We choose levobupivacaine 0.3% keeping in mind the geriatric age group with multiple cardiac comorbidities. The perioperative parameters and nerves blocked are depicted in [Table 1].

Table 1

The perioperative characteristics of the patients

Parameters

Patient 1

Patient 2

Patient 3

Patient 4

Patient 5

Age (years)

78

68

72

65

70

Sex (M/F)

Male

Male

Male

Female

Male

SDH

Right frontotemporoparietal SDH

Left temporo-parietal SDH

Right frontotemporoparietal SDH

Bilateral frontotemporoparietal SDH

Bilateral frontotemporoparietal SDH

Site of burr hole craniotomy

Frontal and temporal

Temporal and parietal

Frontal and parietal

Frontal and parietal, 5cm incision for mini craniotomy done

Frontal and parietal

GCS

E4V5M6

E4V4M6

E3V4M6

E4V5M6

E3V3M6

Comorbidities

Hypertension, diabetes, coronary artery disease, post-PCI with a stent in situ

Hypertension

Hypothyroidism

Hypertension, coronary artery disease

Diabetes, hypertension

Total dose of LA (mL)

14

12

15

28

26

Time taken to administer scalp block (min)

10

12

9

15

20

Nerves blocked

Left supraorbital, supratrochlear, zygomaticotemporal, auriculotemporal, greater auricular, lesser occipital, third occipital

Left supraorbital, supratrochlear, zygomaticotemporal, auriculotemporal, greater auricular, lesser occipital, third occipital

Left supraorbital, supratrochlear, zygomaticotemporal, auriculotemporal, greater auricular, lesser occipital, third occipital

Bilateral supraorbital, supratrochlear, zygomaticotemporal, auriculotemporal, greater auricular, lesser occipital, third occipital

Bilateral supraorbital, supratrochlear, zygomaticotemporal, auriculotemporal, greater auricular, lesser occipital, third occipital

Patient satisfaction (NRS)

8

8

7

8

8

Perioperative complications

Nil

Nil

Nil

Nil

Nil

Rescue analgesia

Nil

Nil

Nil

Injection fentanyl 50 µg for neck pain

Nil

Neurological outcome (mRS)

2

3

1

3

2

Blood pressure (mm Hg)

At scalp block

150/100

150/100

130/84

140/90

148/94

At incision

140/90

152/90

134/86

144/96

146/99

During burr hole

150/90

150/96

132/88

138/94

150/100

Heart rate (beats/min)

At scalp block

56

66

70

58

62

At incision

57

68

74

54

64

During burr hole

55

62

72

56

60

Abbreviations: GCS, Glasgow coma scale; LA, local anesthesia; mRS, modified Rankin scale; NRS, numerical rating scale; SDH, subdural hematoma.


Supraorbital Nerve

A linear array transducer (8–14 MHz) was placed at the medial aspect of the supraorbital rim and the supraorbital foramen was visualized as a depressed break of continuity and using an in-plane technique. LA (1.5 mL) was injected just superficial to the supraorbital foramen to block the supraorbital branch of the frontal nerve ([Fig. 1A]).

Zoom
Fig. 1 Ultrasound-guided scalp block over the right hemisphere. (A) Supraorbital nerve over the supraorbital foramen and the blue circle medially demonstrating the site of supratrochlear nerve block. (B) Zygomaticotemporal nerve block at two landmarks: the deep temporal bone and temporal fascia. (C) Auriculotemporal nerve blocked adjacent to the auriculotemporal artery. (D) Superficial cervical plexus block (honeycomb appearance). (E) Greater occipital nerve block adjacent to the occipital artery. The third occipital nerve block is performed by extending the injection medially along the same fascial plane. The yellow circle indicates the location for placement of the local anesthetic. The red circle indicates the position of the artery.

 

Supratrochlear Nerve

The needle was then directed superomedial to the supraorbital foramen and 1.5 mL of LA was injected subcutaneously extending up to midline to anesthetize the supratrochlear nerve ([Fig. 1A]).


 

Zygomaticotemporal Nerve

The transducer was then placed posterior to the frontal process of the zygomatic bone and the temporal fascia, temporal muscle, and temporal bone were visualized. The zygomaticotemporal nerve was blocked in two planes. The needle was inserted till the deep temporal bone landmark and LA (1.5 mL) was injected between the bone and the temporal muscle. The needle was then withdrawn till the superficial temporal fascia landmark followed by an injection of LA (1.5 mL) above the temporal fascia ([Fig. 1B]).


 

Auriculotemporal Nerve

The transducer probe was then positioned along the line joining the eye's lateral canthus to the ear's tragus. The auriculotemporal artery was first visualized followed by the auriculotemporal nerve adjacent to the artery and LA (1.5 mL) was injected ([Fig. 1C]).


 

Greater Auricular and Lesser Occipital Nerve

Superficial cervical plexus block was performed where the ultrasound probe was positioned at the midpoint of the posterior border of the sternocleidomastoid muscle. The honeycomb-like appearance of the superficial cervical plexus was seen, and LA (4 mL) was injected around the plexus ([Fig. 1D]).


 

Greater Occipital Nerve

The ultrasound probe was placed along the line joining the mastoid process and the occipital protuberance and the occipital artery were visualized and the greater occipital nerve adjacent to the artery following which LA (1.5 mL) was injected using the in-plane approach ([Fig. 1E]).


 

Third Occipital Nerve

The third occipital nerve was anesthetized by the injection of LA (1.5 mL) along the same fascial plane medially extending till the occipital protuberance using the in-plane technique ([Fig. 1E]).

The sensation over the scalp was verified before the incision, and no additional LA was necessary at the surgical site. Multimodal analgesia was administered with intravenous paracetamol (1 g). All patients remained comfortable in the absence of pain throughout the surgery. In one patient, the incision had to be widened to a mini-craniotomy for complete drainage of SDH and the patient complained of neck pain secondary to prolonged positioning but the absence of surgical site pain. The scalp block was not associated with any complications. Patients conveyed experiencing mild brief tolerable pain during the administration of the block with an average visual analogue scale score of two. The patients were asked to grade their general satisfaction with perioperative pain management using a numerical rating scale and the average score reported was eight.


 

 

Discussion

Chronic SDH is a commonly seen neurosurgical pathology occurring in the elderly following trivial trauma with an incidence of 17.2 to 20.6 per 1,00,000 persons per year.[6] Burr hole craniotomy and closed system drainage are effective neurosurgical treatment techniques for SDH that can be performed under LA or GA or scalp block. Zhuang et al compared burr hole evacuation of SDH done under LA and GA and reported that the patients in the GA group suffered from respiratory depression, delayed recovery, nausea, vomiting, and pulmonary infection leading to prolonged hospitalization time and increased cost.[7] Another retrospective study reported that poor GCS at admission, advanced age with multiple comorbidities, and greater SDH volume are factors predictors of poor outcome.[8] In our case, favorable GCS at admission and complete drainage of SDH also contributed to a favorable outcome. In conscious, cooperative patients burr hole craniotomy can be performed under sole LA. However, the use of sedatives and additional analgesic agents is common due to inadequate control of pain leading to hypertension, tachycardia, and a potential risk of adverse cardiovascular events. Many cases may require emergency conversion to GA increasing the potential risk to the patient. The failure rate of LA with dexmedetomidine sedation for burr hole surgery for SDH was reported to be 7.9%.[9]

A successful scalp block minimizes the hemodynamic response to the surgical stimulus by blocking noxious input to the scalp thus decreasing the increase in intracranial pressure, especially so in patients with altered cerebral autoregulation secondary to head injury. It also decreases the requirement for intraoperative anesthetic agents, which can have an adverse effect on the systemic physiology of geriatric patients. It also avoids airway manipulation and reduces postoperative pain and analgesic consumption and facilitates early neurological assessment. Opioid-sparing anesthesia is a key component of enhanced recovery after surgery programs and a successful scalp block reduces the stress response and facilitates early discharge.[10] Anatomical studies have shown that there are significant variations in foramina position and number and the courses of individual nerves.[3] The use of ultrasound helps us avoid complications like administration of LA directly into the supraorbital foramen when targeting the supraorbital nerve, and inadvertent arterial puncture during blockage of nerves adjacent to arterial structures like a zygomaticotemporal and auriculotemporal nerve. Injury to the prevertebral fascia and subarachnoid injection can be avoided during blockage of the greater auricular and lesser occipital nerve.[3] [10]

Classical landmark-based scalp block necessitates the injection of large volumes (40–50 mL) of LA to increase the rate of success that also increases the risk of LA systemic toxicity, which is particularly disastrous in geriatric patients.[11] The rate of increase in serum concentration of LA is rapid due to the intense vascularity of the scalp. With the use of ultrasound, the concentration and volume of LA can be reduced due to accurate identification and precise injection of LA around the target nerves. Complications like facial nerve palsy, ptosis, intracerebral injection, and hematoma have also been reported that can be averted with the use of ultrasound guidance.[3] [10] A review of the literature revealed a single report of successful ultrasound-guided scalp block performed in a patient undergoing awake craniotomy along with sedation using remifentanil.[10] The main limitation is the availability of the ultrasound machine that is expensive and not freely available in resource-constrained setups. However, the benefits resulting from ultrasound guidance outweigh the costs. The practitioner's expertise is also necessary and the operator in the current case series had performed 15 prior successful ultrasound-guided blocks with each block taking an average of 15 minutes to perform, while Tsan et al performed 10 prior successful ultrasound-guided blocks.[10] Hence, the skill is attainable with reasonable experience and practice. Future studies comparing the landmark and ultrasound-guided technique of scalp block by assessing the need for rescue analgesic agents, sedation, conversion to GA, perioperative complications, and overall neurological outcome are necessary to formulate a standard protocol for the administration of scalp block.


 

 

Conflict of Interest

None declared.

Authors' Contributions

A.R. helped in the collection of data, literature review, and manuscript preparation. K.J. helped in the literature review, manuscript preparation, editing, and review. A.K.B. was involved in the literature review, manuscript preparation, editing, and review. K.K. helped in manuscript preparation, editing, and review. The manuscript has been read and approved by all the authors, the requirements for authorship as stated earlier in this document have been met, and each author believes that the manuscript represents honest work if that information is not provided in another form.


Patients' Consent

Written informed consent has been obtained from the patient/patient's kin for the publication of this case series in conformation with the declaration of Helsinki. The patients have given their consent for the publication of images and other clinical information. Patients understand that their names will not be published, and due efforts will be made to conceal their identity but anonymity cannot be guaranteed.



Address for correspondence

Amiya Kumar Barik, DM
Department of Anaesthesia and Intensive Care, Postgraduate Institute of Medical Education and Research
Chandigarh 160012
India   

Publication History

Article published online:
26 June 2025

© 2025. Asian Congress of Neurological Surgeons. This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/)

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Zoom
Fig. 1 Ultrasound-guided scalp block over the right hemisphere. (A) Supraorbital nerve over the supraorbital foramen and the blue circle medially demonstrating the site of supratrochlear nerve block. (B) Zygomaticotemporal nerve block at two landmarks: the deep temporal bone and temporal fascia. (C) Auriculotemporal nerve blocked adjacent to the auriculotemporal artery. (D) Superficial cervical plexus block (honeycomb appearance). (E) Greater occipital nerve block adjacent to the occipital artery. The third occipital nerve block is performed by extending the injection medially along the same fascial plane. The yellow circle indicates the location for placement of the local anesthetic. The red circle indicates the position of the artery.