Superficial cervical plexus block combined with auriculotemporal nerve block for drainage of dental abscess in adults with difficult airways.
Abstract: We report our use of a superficial cervicalplexus block to manage three adults who presented for drainage of dental abscesses. All patients had difficult airways related to severe trismus (preoperative inter-incisor distance [less than or equal to] 1.5 cm). The first two patients, whose abcesses involved both the submandibular and submasseteric spaces, were managed with combined superficial cervical plexus and auriculotemporal nerve block. In a third patient, a superficial cervical plexus block alone was sufficient because the abscess was confined to the submandibular region. The blocks were successful in all three cases with minimal requirement for supplemental analgesia. We recommend the consideration of superficial cervical plexus block and if necessary an auriculotemporal nerve block for the management of selected patients with difficult airways who present for drainage of dental abcesses.

Key Words: cervical plexus block, superficial, auriculotemporal nerve, difficult airway, abscess drainage
Article Type: Case study
Subject: Local anesthesia (Methods)
Local anesthesia (Health aspects)
Nerve block (Methods)
Nerve block (Health aspects)
Tooth diseases (Diagnosis)
Tooth diseases (Care and treatment)
Tooth diseases (Case studies)
Authors: Ling, K.U.
Hasan, M. Shahnaz
Ha, K.O.
Wang, C.Y.
Pub Date: 01/01/2009
Publication: Name: Anaesthesia and Intensive Care Publisher: Australian Society of Anaesthetists Audience: Academic Format: Magazine/Journal Subject: Health Copyright: COPYRIGHT 2009 Australian Society of Anaesthetists ISSN: 0310-057X
Issue: Date: Jan, 2009 Source Volume: 37 Source Issue: 1
Geographic: Geographic Scope: Malaysia Geographic Code: 9MALA Malaysia
Accession Number: 193793191
Full Text: Patients with dental abscess involving facial space infections may present the anaesthetist with quite complex problems for airway management (1,2). However, the use of regional anaesthetic techniques has rarely been described for this group of patients. In our literature search, there was only one previous report on the use of a deep cervical plexus block for surgical decompression in a patient with Ludwig's angina and severe airway compromise (3). Nevertheless, deep cervical plexus block has a high incidence of blocking the phrenic and vagal nerves, which could worsen the respiratory symptoms (4). In this paper, we describe the use of a superficial cervical plexus block combined with an auriculotemporal nerve block for drainage of dental abscess in three adult patients with difficult airways. All three patients have given written consent for publication.

CASE HISTORIES

Case 1

A 31-year-old otherwise healthy female patient presented for an incision and drainage of a facial abscess. She complained of a painful swelling over the rightangle of the mandible. The symptoms were related to a right lower molar toothache of one week's duration, which had not responded to oral antibiotics. On examination, there was a diffuse swelling over the right submasseteric and submandibular regions. The overlying skin was erythematous and warm. She had marked trismus with mouth-opening almost zero. There was no stridor or tachypnoea. She was commenced on intravenous cefuroxime and metronidazole. Flexible nasendoscopy was performed by the ear nose and throat surgeon under local anaesthesia. The arytenoids, vocal cords and epiglottis were normal. There was no pooling of saliva or fullness of the pyriform fossa. A contrast CT scan of her head and neck showed a ring-enhancing swelling of the right submandibular region.

A right superficial cervical plexus block (5 ml ropivacaine 0.75% + 5 ml 1% lignocaine) combined with a right auriculotemporal nerve block (2.5 ml ropivacaine 0.75% + 2.5 ml 1% lignocaine) were performed. Within five minutes the patient felt pain-free. Incision and drainage commenced 15 minutes after the block was performed. Fentanyl 50 [micro]g and midazolam 1 mg were given intravenously (IV).

A 2 cm right submandibular skin incision was made down to the subplatysmal layer, followed by blunt dissection towards the right submandibular fossa. Twenty ml of thick pus was drained. The patient felt some mild discomfort when the surgeon dissected into the deeper structures; however this lasted only about two minutes. The surgery and anaesthesia were otherwise without incident and following an uneventful recovery, she was discharged two days later. A week later she was reviewed at our Oral and Maxillofacial Surgery Clinic. The swelling had subsided and her mouth-opening was 2.5 cm. The right lower molars were subsequently removed under local anaesthesia in the clinic.

Case 2

A 28-year-old female patient was referred from a dental clinic for management of a firm swelling on the lateral border of her left mandible that had not responded to oral antibiotics. She had a one-month history of toothache related to the lower left wisdom tooth and swelling of five days duration, with progressive limitation of mouth-opening. On examination, there was a firm and tender swelling on the left submasseteric region with minimal skin redness and increased skin temperature. Her mouth-opening was only 0.5 cm of interincisor distance. A contrast CT scan showed a localised collection in the left submasseteric space.

In the operating theatre, a left superficial cervical plexus block (5 ml 0.75% ropivacaine + 5 ml 1% lignocaine) and left auriculotemporal nerve block (2.5 ml 0.75% ropivacaine + 2.5 ml 1% lignocaine) were performed. In less than 10 minutes, the patient was pain-free.

Incision and drainage commenced 15 minutes after the block was performed. Fentanyl 50 [micro]g and midazolam 1 mg were given IV The surgeon made a 2.5 cm skin incision in the left submandibular region and tunnelled towards the submasseteric space. A total of 20 ml of pus was drained. The patient complained of mild pain when the surgeon dissected into the deeper structures but this was short-lived. The surgery and anaesthesia were otherwise uneventful and she was discharged two days later. She was reviewed 10 days later at Oral and Maxillofacial Surgery Clinic. She had minimal residual swelling and a mouth-opening of 2 cm. The lower left wisdom tooth was removed under local anaesthesia on the same visit.

Case 3

A 25-year-old female patient presented to our accident and emergency unit with two-day history of fever, pain and swelling involving the oral cavity and neck. The swelling progressed and was associated with limited mouth-opening and distortion of the floor of the mouth. The patient also complained of dysphagia and odynophagia, but had no stridor or dyspnoea. Examination showed a marked swelling over the right submandibular and submental spaces with elevation of the tongue. The swelling was very tender and mouth-opening was limited to 1.5 cm. Her temperature was 37.5[degrees]C. A plain radiograph of the neck showed soft tissue swelling with narrowed posterior pharyngeal and supraglottic spaces. A CT scan of the neck demonstrated a large hypodense collection with rim enhancement measuring 4.5 x 1.6 x 1.5 cm in the right parapharyngeal space, extending to the retropharyngeal space with surrounding soft tissue oedema. Also noted was bilateral cervical and submandibular lymphadenopathy.

In view of the large neck swelling with the potential risk of upper airway obstruction, surgical decompression was needed. A right superficial cervical plexus block was performed using 10 ml of 0.5% levobupivacaine. The patient had pain relief after approximately two minutes and she was able to open her mouth and move her head without any pain.

Incision and drainage was done 20 minutes later. Fentanyl 25 [micro]g and midazolam 1 mg were given IV An incision was made 2 cm below the mandible. The subcutaneous tissues and the investing layer over the submandibular gland were opened, and with blunt dissection deep to the submandibular gland the pus was drained. This caused some mild pain which was controlled with a further bolus of fentanyl 25 [micro]g IV Three infected teeth were then extracted under local anaesthesia with an inferior dental block. The surgery and anaesthesia were uneventful and she was discharged home on the next day.

DISCUSSION

Patients with dental abscess, particularly those with facial space infections requiring incision and drainage, can present difficult airway problems. If general anaesthesia is planned, skilled airway management is critical. Awake fibreoptic intubation is often the safest option (5), although this may be associated with its own complications (6). Inhalational induction and intubation without muscle relaxants is another option, but there is a risk of losing the airway in patients with known trismus. Darshane and colleagues have recently reported that if trismus (defined as [less than or equal to] 2 cm inter-incisor distance) occurs with superficial infection, there is only a 50% chance that the patient's mouth-opening will improve after induction of anaesthesia (7). In our three cases, the preoperative inter-incisor distance was [less than or equal to] 1.5 cm. Another option is tracheostomy under local anaesthetic. However, there is a potential for bacterial contamination of the tracheostomy site and extension of the infection (8). Nevertheless, tracheostomy remains a life-saving procedure in the case of a compromised airway obstruction. Incision and drainage under local infiltration would be difficult as the anaesthesia can be suboptimal because of the cellulitis and this may not permit a thorough exploration of the wound.

For these reasons, a superficial cervical plexus block is an option worth considering in selected cases. It is easy to perform and the success rate is high (9). The injection site is usually far enough away from the infected area for it to be performed safely. A superficial cervical plexus alone may be adequate for most neck and face abscesses, but the auriculotemporal nerve can also be blocked if necessary.

The superficial cervical plexus is approached at the midpoint of the posterior border of the sternocleidomastoid muscle. The patient's head is turned to the side opposite the surgery and the sternocleidomastoid muscle identified by asking the patient to lift his or her head. A line is drawn laterally from the cricoid cartilage and this usually crosses the posterior border of the sternocleidomastoid muscle at the point where the nerves of the plexus emerge. Our technique involves a single injection. A short bevel needle 24-gauge x 1 inch needle (24 gauge, Plexufix, B. Braun Melsungen AG, Nogent-le-Rotrov, France) is inserted immediately behind the muscle at rightangles to the skin until it 'pops' through the cervical fascia. After negative aspiration the local anaesthetic is injected. If the needle is in the correct tissue plane, an injection of the local anaesthetic will be seen to flow up and down the posterior border of the muscle (10). The needle should not be advanced more than 1 to 2 cm.

We perform an auriculotemporal nerve block by inserting a 24-gauge x 1 inch short bevel needle (B. Braun Melsungen AG, Nogent-le-Rotrov, France) at rightangles to the skin between the pulsation of the artery and the tragus. After negative aspiration, the local anaesthetic is injected (11).

Despite its relative safety, superficial cervical plexus anaesthesia requires certain precautions. The main complications relate to intravascular injection of local anaesthetic and haematoma formation. There is a possibility of direct intea-arterial injection, which can be avoided by ensuring that the needle is not inserted more than 1 to 2 cm. Phrenic, vagus, glossopharyngeal and cervical sympathetic chain nerve involvement have also been reported, although these are associated more with a deep cervical plexus block.

Drugs for resuscitation and equipment to deal with difficult intubation and emergency tracheostomy should be available in the event of failure or complication.

As long as these precautions are in place, we recommend the use of a superficial cervical plexus block, combined with an auriculotemporal nerve block if necessary, for selected patients with dental abcesses requiring urgent incision and drainage, who have difficult airways related to swelling and limited mouth-opening.

REFERENCES

(1.) Green AW, Flower EA, New NE. Mortality associated with odontogenic infection. Br Dent J 2001; 190:529-530.

(2.) Neff SPW, Merry AF, Anderson BJ. Airway management in Ludwig's angina. Anaesth Intensive Care 1999; 27:659-661.

(3.) Mehrotra M, Mehrotra S. Decompression of Ludwig angina under cervical block. Anesthesiology 2002; 97:1625-1626.

(4.) Pandit JJ, Satya-Krishna R, Gration P Superficial or deep cervical plexus block for carotid endarterectomy: a systematic review of complications. Br J Anaesth 2007; 99:159-169.

(5.) Ovassapian A, Tuncbilek M, Weitzel EK, Joshi CW Airway management in adult patients with deep neck infections: a case series and review of the literature. Anesth Analg 2005;100:585-589.

(6.) Benumof JL. Management of the difficult adult airway. With special emphasis on the awake tracheal intubation. Anesthesiology 1991; 75:1087-1110.

(7.) Darshane S, Groom P, Charters P Responsive Contingency Planning: a novel system for anticipated difficulty in airway management in dental abscess. Br J Anaesth 2007; 99:898-905.

(8.) Snow N, Lucas AE, Grau M, Steiner M. Purulent mediastinal abscess secondary to Ludwig's angina. Arch Otolaryngol 1983; 109:53-55.

(9.) Stoneham MD, Knighton JD. Regional anaessthesia for carotid endarterectomy. Br J Anaesth 1999; 82:910-929.

(10.) Pinnock CA, Fischer HBJ, Jones RP Superficial Cervical Plexus Block. In: Peripheral Nerve Blockade, 1st ed. Edinburgh, United Kingdom: Churchill Livingstone, Harcourt Brace and Company Limited 1998. p. 140-141.

(11.) Pinnock CA, Fischer HBJ, Jones RP Auriculotemporal nerve block. In: Peripheral Nerve Blockade, 1st ed. Edinburgh, United Kingdom: Churchill Livingstone, Harcourt Brace and Company Limited 1998. p. 145.

K. U. LING *, M. SHAHNAZ HASAN *, K. O. HA ([dagger]), C. Y. WANG ([double dagger])

Department of Anaesthesia, Faculty of Medicine, University Malaya, Lembah Pantai, Kuala Lumpur, Malaysia

* M.B., B.S., M.Anaes., Lecturer.

([dagger]) B.D.S., ED.S.R.C.S. (England), Lecturer, Department of Oral and Maxillofacial Surgery.

([double dagger]) M.B., Ch.B., ER.CA, Professor.

Address for reprints: Dr C. Y. Wang, Department of Anaesthesia, Faculty of Medicine, University Malaya, Lembah Pantai, 50603 Kuala Lumpur, Malaysia.

Accepted by publication on August 18, 2008.
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