Full text of DOI:10.1007/BF03016881

REGIONAL ANESTHESIA AND PAIN
951
Continuous mandibular nerve block for pain
relief. A report of two cases
[Analgésie par blocage continu du nerf maxillaire inférieur. Étude de deux cas.]
Baljit Singh MD, Vinay Bhardwaj DA
Purpose: Mandibular nerve block allows surgery to be performed
on the mandible. However, pain in the postoperative period needs
to be treated with opioids or non-steroidal anti-inflammatory
agents which have undesirable side effects. We examine the feasi-
bility of continuous mandibular nerve block with 0.25% bupiva-
caine top-ups using a catheter for intraoperative and postoperative
pain relief in two patients with a fracture of the mandible.
Methods: Using the lateral extraoral approach, the mandibular
nerve was approached with an 18-gauge indwelling iv cannula in
two patients undergoing repair of a fractured mandible under gen-
eral anesthesia. After removing the needle, an 18-gauge epidural
catheter was inserted into the cannula which was then removed.
The catheter was tunnelled subcutaneously to emerge at the later-
al aspect of the forehead. Two to 4 mL bupivacaine 0.25% were
injected on a 12-hr basis and the catheter was kept in place for
seven days.
mandibule sous anesthésie générale. Après le retrait de l’aiguille, un
cathéter péridural de calibre 18 a été inséré dans la canule qui a été
enlevée. Le cathéter a été tunnellisé par voie sous-cutanée pour
ressortir à la face latérale du front. De 2 à 4 mL de bupivacaïne à
0,25 % ont été injectés aux 12 h et le cathéter a été maintenu en
place pendant sept jours.
Résultats : Les deux patients ont reçu une excellente analgésie et
aucun analgésique postopératoire parentéral ou oral n’a été demandé.
Aucun effet secondaire n’a été noté.
Conclusion : Le blocage continu du nerf maxillaire inférieur avec des
doses d’appoint de 2–4 mL de bupivacaïne à 0,25 % injectés deux
fois par jour par un cathéter fournit une excellente analgésie aux
patients opérés pour une fracture de la mandibule. Cette méthode a
des implications sur la gestion de la douleur d’autre source dans la
région mandibulaire.
Results: Both patients had excellent pain relief and no parenteral
or oral analgesics were required throughout the postoperative peri-
od. No side effects were noted.
Conclusions: Continuous mandibular nerve block with 2–4 mL
0.25% bupivacaine top-ups injected twice a day through a catheter
provides excellent pain relief in patients with a fracture of the
mandible. This method may have implications for the management
of pain of other etiology in the mandibular region.
mandibular nerve block is often performed
for diagnostic, therapeutic and anesthetic
purposes for surgery involving the
A
mandibular region.1 Advantages of a nerve
block include excellent pain relief and avoidance of the
side effects associated with the use of analgesics. We
report the technique of continuous mandibular nerve
block for pain relief in two patients who underwent
surgery for repair of a fractured mandible.
Objectif : Le blocage du nerf maxillaire inférieur permet de procéder
à une intervention chirurgicale mandibulaire. Cependant, la douleur
postopératoire doit être traitée avec des opioïdes ou des anti-inflam-
matoires non-stéroïdiens qui présentent des effets secondaires indési-
rables. Nous avons vérifié la faisabilité d’un blocage continu du nerf
maxillaire inférieur avec des doses d’appoint de bupivacaïne à 0,25 %
au moyen d’un cathéter pour l’analgésie peropératoire et postopéra-
toire chez deux patients victime d’une fracture de la mandibule.
Case 1
A 74-yr-old, 52 kg, male with gun-shot injury to the
face with fracture of the left ramus of the mandible, was
scheduled for an elective open reduction and internal
fixation. The patient had difficulty opening the mouth
(3 cm, best effort) due to pain. Surgery was planned
under general anesthesia with a continuous mandibular
nerve block for intraoperative and postoperative anal-
gesia. The patient was familiarized with the visual ana-
Méthode : Le nerf maxillaire inférieur a été atteint, en utilisant une
approche extra-orale, avec une canule iv à demeure de calibre 18
chez deux patients devant subir la réparation d’une fracture de la
From the Department of Anaesthesiology, Lady Hardinge Medical College and Associated Hospitals, New Delhi, India.
Address correspondence to: Dr. Baljit Singh, Associate Professor, Department of Anaesthesiology, Lady Hardinge Medical College and
Associated Hospitals, New Delhi 110 001, India. E-mail: dr_baljit@yahoo.com or rasvin666@rediffmail.com
Accepted for publication May 17, 2002.
Revision accepted August 14, 2002.
CAN J ANESTH 2002 / 49: 9 / pp 951–953

952
CANADIAN JOURNAL OF ANESTHESIA
FIGURE 1 The iv cannula on reinsertion contacting mandibular
nerve. A) zygomatic arch; B) lateral pterygoid plate; C) mandibu-
lar nerve.
logue scale (VAS) of 0–10. After giving informed con-
sent, anesthesia was induced with thiopentone and
orotracheal intubation was facilitated with succinyl-
choline. Neuromuscular blockade was achieved with
vecuronium and anesthesia was maintained with O2
and N2O using controlled ventilation. The left side of
the face was prepared for the block with the extraoral
lateral approach. An 18-gauge indwelling iv cannula
was inserted at the midpoint of the lower border of the
zygomatic arch and advanced perpendicular to the face
until it contacted the lateral pterygoid plate. The
length of the cannula outside of the skin was marked
and the cannula was withdrawn and redirected slightly
posteriorly to reach behind the posterior border of the
lateral pterygoid plate (Figure 1).
FIGURE 2A Epidural catheter inserted into the iv cannula after
removing the needle.
Once the marked length was reached without con-
tacting the bone indicating its passage behind the pos-
terior border of the lateral pterygoid plate, it was
advanced further by 0.5 cm. The needle from the can-
nula was removed and an 18-gauge epidural catheter
(B.Braun, Melsungen AG, Germany) was threaded into
the cannula (Figure 2A) which was then removed main-
taining inward pressure on the epidural catheter. It was
then tunnelled sc to emerge at the lateral aspect of the
forehead and fixed there with a filter (Figure 2B). A
bolus dose of 4 mL of 0.25% bupivacaine was injected
through the catheter and the surgeon was allowed to
proceed. Surgery lasted about two hours and no opi-
oids were given in the intraoperative period. After
surgery, a top-up dose of 3 mL of 0.25% bupivacaine
was given and neuromuscular blockade was reversed.
Following extubation, the patient was conscious and
FIGURE 2B Cannula removed and catheter tunneled sc.

Singh et al.: CONTINUOUS MANDIBULAR NERVE BLOCK
953
pain free and was moved to the recovery room. In the
evening the pain score on the VAS was measured as ‘1’.
A top-up dose of 4 mL of 0.25% bupivacaine was given
at night and repeated every 12 hr for two days.
Thereafter, the regimen of 12-hr top-ups was changed
to 3 mL for two days and 2 mL for the next three days.
Pain was measured before every top-up. The maximum
pain score noted throughout the postoperative period
was ‘2’ on one occasion on the second day. On the sev-
enth day, to assess the need to continue top-up admin-
istration, the evening dose was omitted. The next
morning, pain was measured to be ‘1’. The catheter was
then removed and no evidence of infection at the exit
site and subcutaneous track was noted. There was no
motor or sensory deficit in the mandibular region and
the patient was discharged on the tenth day.
catheter, which is about 0.5 cm from the tip, as close
to the nerve as possible. In case 2, no further advance
of the cannula was necessary as the catheter was insert-
ed from the opposite end (injection port end) which
has no lateral eyes. The catheter was tunnelled sc, away
from the surgical field, and the filter was used to min-
imize the risks of infection.
Open reduction and internal fixation can be done
using a single-shot mandibular nerve block, but the
need for opioids or non-steroidal anti-inflammatory
drugs to relieve pain may result in adverse effects,
negating the benefits of surgery conducted under
local anesthesia.
In conclusion, we performed continuous mandibu-
lar nerve blocks using bupivacaine 0.25% injected
through an 18-gauge epidural catheter placed via an
18-gauge iv cannula. The block was easy to perform
and provided adequate intraoperative and postopera-
tive analgesia. This technique may prove to be useful
in the management of pain of other etiology in the
mandibular region.
Case 2
A 53-yr-old male was scheduled for open reduction
and fixation of a fracture of the left ramus of the
mandible sustained during a fight. After giving
informed consent, anesthesia was induced and, using
an 18-gauge iv cannula, the injection port end of an
18-gauge epidural catheter was inserted as in case 1
and 4 mL of 0.25% bupivacaine were injected. Surgery
lasted one hour and 25 min and no analgesic was
given intraoperatively. One hour after surgery the pain
score was noted to be ‘2’ and the patient could open
his mouth and talk without any difficulty. A top-up of
3 mL 0.25% was given at night, was continued every
12 hr subsequently and reduced to 2 mL after two
days. VAS scores noted before every top-up remained
between ‘0–2’ throughout the postoperative period.
On omitting a dose on the seventh day, no increase in
pain score was noted and the catheter was removed.
There were no complications and the patient was dis-
charged on the eighth day.
References
1 Wedel DJ, Brown DL. Nerve blocks. In: Miller RD
(Ed.). Anaesthesia, 3rd ed. London, England: Churchill
Livingstone, 1990: 1426.
2 Singh B, Srivastava SK, Dang R, Gombar KK, Gombar
S. Anatomic considerations in relation to the mandibu-
lar nerve block. Reg Anesth 1993; 18: 181–3.
Discussion
Mandibular nerve blocks can be easily performed by
the lateral extraoral approach1 or by the intraoral
approach. The lateral extraoral approach was preferred
because our patients had difficulty in opening the
mouth and also because we planned to place a catheter
for postoperative analgesia. We used an 18-gauge iv
cannula to place the epidural catheter instead of a
Tuohy needle (which has a large tip), to minimize pos-
sibility of bleeding from the pterygoid plexus of veins.
In case 1, the cannula was advanced by an addi-
tional 0.5 cm over the pre-measured distance from the
skin to the lateral pterygoid plate. This increase is not
required to reach the mandibular nerve,2 but was des-
tined to bring the most distal eye of the epidural