CASE REPORTS
Iatrogenic Traumatic Brain Injury During Tooth Extraction Mark Troxel, DVM, DACVIM (Neurology)
ABSTRACT An 8 yr old spayed female Yorkshire terrier was referred for evaluation of progressive neurological signs after a routine dental prophylaxis with tooth extractions. The patient was circling to the left and blind in the right eye with right hemiparesis. Neurolocalization was to the left forebrain. MRI revealed a linear tract extending from the caudal oropharynx, through the left retrobulbar space and frontal lobe, into the left parietal lobe. A small skull fracture was identified in the frontal bone through which the linear tract passed. Those findings were consistent with iatrogenic trauma from slippage of a dental elevator during extraction of tooth 210. The dog was treated empirically with clindamycin. The patient regained most of its normal neurological function within the first 4 mo after the initial injury. Although still not normal, the dog has a good quality of life. Traumatic brain injury is a rarely reported complication of extraction. Care must be taken while performing dental cleaning and tooth extraction, especially of the maxillary premolar and molar teeth to avoid iatrogenic damage to surrounding structures. (J Am Anim Hosp Assoc 2015; 51:114– 118. DOI 10.5326/JAAHA-MS-6094)
Introduction
of progressive neurological signs following a dental cleaning and
Traumatic brain injury (TBI) is a common disorder in veterinary
extraction of several teeth. The referring veterinarian performed a
medicine, most often the result of the patient being hit by a motor
routine dental cleaning and extracted several teeth 2 days prior to
vehicle. Other forms of TBI resulting from penetrating gunshot
admission to MVRH. While extracting tooth 210, the dental
wounds or bite wounds are also somewhat common. Iatrogenic
elevator slipped and the veterinarian thought it entered only the left
orbital penetration is a relatively common complication of tooth
retrobulbar space. The dog had a slow recovery from anesthesia and
1
extraction. However, iatrogenic TBI during dental procedures
scleral hemorrhage was noted. The patient was discharged that
rarely has been reported. In one case, a patient developed a
evening to the owner with instructions to give meloxicam (0.1 mg/
retrobulbar and intracranial abscess following tooth extraction and
kg per os [PO] q 24 hr) and clindamycin (6.9 mg/kg PO q 12 hr).
1
subsequently died 48 hr after the procedure. This case report
The dog’s clinical signs progressed the evening of discharge to
describes the MRI findings and successful treatment of a dog that
agitation, vocalizing, and difficulty standing and walking. Several
suffered iatrogenic TBI during extraction of tooth 210 when a
hours later, the dog was unable to stand or walk, was falling to the
dental elevator slipped.
right, and appeared to be blind in the right eye.
Case Report
Physical examination revealed mild tachycardia (150 beats/min),
An 8 yr old spayed female Yorkshire terrier was referred to
mild tachypnea (50 breaths/min), mild erythema in the vicinity of
Massachusetts Veterinary Referral Hospital (MVRH) for evaluation
teeth 209 and 210, a 1 cm 3 3–4 mm bruise on the left upper eyelid,
From the Massachusetts Veterinary Referral Hospital, Woburn, MA.
CSF, cerebrospinal fluid; IM, intramuscular; MVRH, Massachusetts
The dog was taken to a local emergency clinic for evaluation.
Correspondence: (M.T.) [email protected]
Veterinary Referral Hospital; OD, oculus dexter; OS, oculus sinister; OU, oculus uterque; PO, per os; T1WI, T1-weighted image; T2WI, T2-weighted image; TBI, traumatic brain injury; TE, echo time; TR, repetition time
114
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Iatrogenic Traumatic Brain Injury During Tooth Extraction
and severe scleral hemorrhage with exophthalmos oculus sinister
inversion recovery (TR, 7000 msec; TE, 90 msec), transverse
(OS). Neurological examination revealed an absent menace
T2*HEMO images (TR, 605 msec; TE, 23 msec), and precontrast
response oculus dexter (OD) and slow to absent pupillary light
transverse T1-weighted images (T1WI; TR, 602 msec; TE, 18 msec).
reflex oculus uterque (OU). The remainder of the neurological
IV contrast agentf (0.1 mmol/kg IV) was administered and
exam was reportedly normal. Intraocular pressures were normal
transverse (TR, 602 msec; TE, 18 msec), sagittal (TR, 412 msec;
(17–26 mm Hg OU) and fluorescein staining was negative. The dog
TE, 18 msec), and dorsal (TR, 400 msec; TE, 18 msec) postcontrast
was prescribed buprenorphine (0.018 mg/kg IV q 8 hr) for pain
T1WI images were obtained.
management. Mannitol (1 g/kg IV) was administered at the time of
The MRI (Figure 1) showed a linear tract on T2WI
admission to reduce intracranial pressure and was repeated twice
(parasagittal) extending caudodorsally from the left orbit, through
more at 4 hr intervals. Ten hours after admission, the dog was still
a skull fracture into the brain, ending in the left parietal lobe that
ataxic, but would trot for a short period of time. By 13 hr after
was consistent with intracranial penetration of the dental elevator.
admission, the dog’s ability to walk had improved significantly and
On transverse images, the tract was hyperintense and relatively well
she was falling only when changing directions suddenly. At that
defined on T2WI and poorly defined on T1WI. There was a
point in time, the emergency veterinarian started IV fluids (0.9%
hyperintense region at the dorsal extent of the tract on T2WI that
Na chloride at 7 mL/hr) for dehydration. The dog was discharged a
was hypointense on T1WI, suggestive of fluid accumulation. On
few hours later. At discharge, the dog was able to walk without
transverse T2*HEMO images, there was hypointensity in the
assistance, but was circling to the left.
ventral portion of the tract that was consistent with hemorrhage.
The patient was re-evaluated the following morning by its
There also was an area of hypointensity in each lateral ventricle,
regular veterinarian who then referred the patient to MVRH.
suggestive of intraventricular hemorrhage. The linear tract was
Physical examination revealed a normal heart rate (124 beats/min)
observed to pass through the left lateral ventricle on transverse
and respiratory rate (40 breaths/min). The dog had a bruised upper
images at the level of the thalamus, explaining the likely source of
eyelid OD, severe episcleral hemorrhage OS, a small ventral
intraventricular hemorrhage. Following administration of the IV
episcleral hemorrhage OD, and pain opening the mouth.
contrast agent, there was mild blushing contrast enhancement
Neurological examination revealed that the dog was ambulatory
along the tract. There was also a moderate amount of T2-weighted
with circling to the left and occasional falling to the right, right
hyperintense signal in the surrounding brain parenchyma that was
hemiparesis, and mild to moderate proprioceptive ataxia in all four
isointense on T1WI but that did not contrast enhance, suggestive of
limbs. There was no menace response OD, and the patient did not
cerebral edema.
track cotton balls thrown in the right visual field. The remainder of
Cerebrospinal fluid (CSF) analysis was performed and a mild
the cranial nerve examination was within normal limits. Absent
mixed-cell pleocytosis was identified. The nucleated cell count was
conscious proprioception and hopping were noted in the right
6 cells/lL (reference range, ,5 cells/lL; differential cytology: 58%
pelvic limb with delayed conscious proprioception and hopping in
nondegenerate neutrophils, 35% small to medium lymphocytes,
the right thoracic limb. Postural reactions on the left side and the
and 7% large mononuclear cells). Cytology also demonstrated the
remainder of the neurological examination were within normal
presence of red blood cells within large mononuclear cells
limits. Neuroanatomical localization was to the left forebrain
(erythrophagocytosis), suggestive of hemorrhage prior to CSF
(cerebral hemisphere/thalamus). Screening blood tests were normal
sampling.
other than elevated lactate (2.5 mmol/L; reference range, 0.3–1.8
The patient recovered normally following MRI and CSF
mmol/L). In-house prothrombin time and activated partial
sampling and was discharged the same day with clindamycing (10
thromboplastin time were within normal limits.
mg/kg PO q 12 hr). CSF aerobic and anaerobic bacterial cultures
On day 2, MRI of the head was performed using a 1.5 tesla a
b
were negative, but the clindamycin was continued because CSF
magnet . The dog was premedicated with morphine (0.3 mg/kg
bacterial culture can be negative even in the face of histologically
intramuscular [IM]) and dexmedetomidinec (0.01 mg/kg IM).
confirmed bacterial meningoencephalitis.
d
General anesthesia was induced with propofol (5 mg/kg IV),
One month after the initial MRI, the patient was re-examined
administered to effect to allow endotracheal intubation, and
at MVRH for a follow-up MRI. The owner reported that the dog
maintained with isofluranee. A routine MRI scan of the head was
was less ataxic and had started to use stairs again but still appeared
performed, including sagittal (repetition time [TR], 2900 msec;
blind in the right eye. The neurological exam was improved but still
echo time [TE], 120 msec) and transverse T2-weighted images
not normal. The patient was able to walk a straight line without
(T2WI; TR, 3000 msec; TE, 100 msec), transverse fluid-attenuated
falling but still had absent postural reactions in the right limbs and
JAAHA.ORG
115
FIGURE 1 MRI images obtained 2 days after iatrogenic traumatic brain injury during tooth extraction. Parasagittal T2-weighted (A) and
postcontrast T1-weighted (B) images show a linear tract extending from a fracture in the frontal bone (arrow), through the frontal lobe, and ending in the parietal lobe. Transverse T2-weighted (C) images at the level of the caudate nuclei show an indistinct intra-axial hyperintense tract through the brain parenchyma with surrounding cerebral edema of the left caudate nucleus and internal capsules. Transverse T2*HEMO images (D) show an area of marked hypointensity in the ventral frontal lobe consistent with hemorrhage. There is also an area of hypointensity in the left lateral ventricle consistent with intraventricular hemorrhage secondary to puncture of the left lateral ventricle (not shown). absent vision OD. Neurolocalization of the lesion was still to the
other than continued mild postural reaction deficits in the right
left forebrain. Repeat MRI showed continued presence of the linear
thoracic and pelvic limbs. MRI at that time showed continued
tract through the brain as described above, but the cerebral edema
presence of traumatic brain injury, but the lesion was smaller than
was significantly reduced. The clindamycin was discontinued and
at the time of original injury (Figure 2).
the patient was discharged. Three months later, the patient was brought in for another
Discussion
MRI. Neurologic examination revealed a normal gait and intact
Ophthalmic complications of dental disease are common in dogs
vision in both eyes. The dog still had delayed postural reactions in
and cats because of the proximity of the caudal maxillary teeth and
the right thoracic and pelvic limbs. Neurolocalization was still to
the ventral aspect of the orbit.2 Several cases of iatrogenic injury to
the left forebrain. MRI at that time showed that the tract was
periorbital structures have been reported previously, but to the
smaller than in the previous studies.
author’s knowledge, only one case of intracranial disease following
The patient was evaluated once again 1 yr after the original
tooth extraction has been reported in the veterinary literature.1 In
injury. The neurological examination was within normal limits
that case, computed tomography showed a retrobulbar abscess with
116
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Iatrogenic Traumatic Brain Injury During Tooth Extraction
FIGURE 2
MRI images obtained 1 yr after iatrogenic traumatic brain injury. The linear tract through the brain is much less obvious on
parasagittal T2-weighted images (A), but residual brain damage is visible on transverse T2-weighted (B), fluid-attenuated inversion recovery (fluid-attenuated inversion recovery; C), and postcontrast T1-weighted (D) images. There is a region of noncontrast-enhancing hypointensity lateral to the left lateral ventricle on the fluid-attenuated inversion recovery and T1-weighted images that is hyperintense on T2-weighted images. This is suggestive of brain necrosis at that location.
extension through the frontal bone into the calvaria with an
and medial pterygoid muscles.1,2 The roots of the maxillary fourth
associated intracranial abscess. The patient died 48 hr following the
premolar and both molar teeth are located within the maxillary
dental procedures despite draining the retrobulbar abscess, IV
bone in close proximity to the orbit.1–3 Periodontal pathology can
fluids, and IV antibioitics.1
weaken the bone, leading to orbital penetration during tooth
Penetration of the orbital floor during tooth extraction is
extraction.3,4 Additionally, the orbits in brachycephalic breeds are
relatively uncommon but can occur due to multifactorial causes,
positioned more rostrally than mesaticephalic and dolichocephalic
including regionally thin bony structures, periodontal pathology,
breeds, increasing the risk of iatrogenic injury to the orbit and
1
and improper extraction techniques. In dogs and cats, the bony
globe during tooth extraction.2
orbit is incomplete and the ventral aspect of the orbit is comprised
Several recommendations have been reported to reduce the
of soft tissues, including the zygomatic salivary gland, orbital fat,
risk of iatrogenic trauma to surrounding soft-tissue structures.
JAAHA.ORG
117
Dental radiographs ideally should be obtained prior to tooth extraction to help gauge the depth of the roots and to assess periodontal pathology.
1
FOOTNOTES a b
Teeth with multiple roots should be
c
sectioned prior to extraction.1,3,4 The elevator should be applied
d
with gentle and steady rotational pressure for 10–30 sec at a time
e
and advanced apically using a slow, twisting action.
1,3,4
Finally, to
help reduce the risk of accidental slippage, it is recommended that
f g
Phillips Gyroscan ACS-NT; Best, The Netherlands Morphine sulfate injection, USP; West-ward, Eatontown, NJ Dexdomitor; Zoetis, Florham Park, NJ. PropoFlo; Abbot, North Chicago, IL Fluriso; Vet One, Boise, ID Magnevist Injection; Bayer HealthCare Pharmaceuticals Inc., Wayne, NJ Clintabs; Virbac AH, Inc., Fort Worth, TX,
the elevator be held down the shaft of the instrument and a finger placed near the tip of the elevator to act as a ‘‘stop’’ should the elevator slip.
1
Conclusion Fortunately, the patient in this case report survived the iatrogenic traumatic brain injury with minimal residual neurological deficits. With attention to detail and proper handling of dental instruments, iatrogenic orbital and brain injury should remain an uncommon occurrence in veterinary medicine.
118
JAAHA
|
51:2 Mar/Apr 2015
REFERENCES 1. Smith MM, Smith EM, La Croix N, et al. Orbital penetration associated with tooth extraction. J Vet Dent 2003;20:8–17. 2. Ramsey DT, Marretta SM, Hamor RE, et al. Ophthalmic manifestations and complications of dental disease in dogs and cats. J Amer Anim Hosp Assoc 1996;32:215–24. 3. Wiggs RB, Lobprise HB. Oral surgery. In: Wiggs RB, Lobprise HB, eds. Veterinary dentistry: principles and practice. Philadelphia (PA): Lippincott-Raven; 1997:236–57. 4. Verstraete FJM. Exodontics. In: Slatter D, ed. Textbook of small animal surgery. Philadelphia (PA): Saunders; 2003:2696–709.
Iatrogenic Traumatic Brain Injury During Tooth Extraction Mark Troxel, DVM, DACVIM (Neurology)
ABSTRACT An 8 yr old spayed female Yorkshire terrier was referred for evaluation of progressive neurological signs after a routine dental prophylaxis with tooth extractions. The patient was circling to the left and blind in the right eye with right hemiparesis. Neurolocalization was to the left forebrain. MRI revealed a linear tract extending from the caudal oropharynx, through the left retrobulbar space and frontal lobe, into the left parietal lobe. A small skull fracture was identified in the frontal bone through which the linear tract passed. Those findings were consistent with iatrogenic trauma from slippage of a dental elevator during extraction of tooth 210. The dog was treated empirically with clindamycin. The patient regained most of its normal neurological function within the first 4 mo after the initial injury. Although still not normal, the dog has a good quality of life. Traumatic brain injury is a rarely reported complication of extraction. Care must be taken while performing dental cleaning and tooth extraction, especially of the maxillary premolar and molar teeth to avoid iatrogenic damage to surrounding structures. (J Am Anim Hosp Assoc 2015; 51:114– 118. DOI 10.5326/JAAHA-MS-6094)
Introduction
of progressive neurological signs following a dental cleaning and
Traumatic brain injury (TBI) is a common disorder in veterinary
extraction of several teeth. The referring veterinarian performed a
medicine, most often the result of the patient being hit by a motor
routine dental cleaning and extracted several teeth 2 days prior to
vehicle. Other forms of TBI resulting from penetrating gunshot
admission to MVRH. While extracting tooth 210, the dental
wounds or bite wounds are also somewhat common. Iatrogenic
elevator slipped and the veterinarian thought it entered only the left
orbital penetration is a relatively common complication of tooth
retrobulbar space. The dog had a slow recovery from anesthesia and
1
extraction. However, iatrogenic TBI during dental procedures
scleral hemorrhage was noted. The patient was discharged that
rarely has been reported. In one case, a patient developed a
evening to the owner with instructions to give meloxicam (0.1 mg/
retrobulbar and intracranial abscess following tooth extraction and
kg per os [PO] q 24 hr) and clindamycin (6.9 mg/kg PO q 12 hr).
1
subsequently died 48 hr after the procedure. This case report
The dog’s clinical signs progressed the evening of discharge to
describes the MRI findings and successful treatment of a dog that
agitation, vocalizing, and difficulty standing and walking. Several
suffered iatrogenic TBI during extraction of tooth 210 when a
hours later, the dog was unable to stand or walk, was falling to the
dental elevator slipped.
right, and appeared to be blind in the right eye.
Case Report
Physical examination revealed mild tachycardia (150 beats/min),
An 8 yr old spayed female Yorkshire terrier was referred to
mild tachypnea (50 breaths/min), mild erythema in the vicinity of
Massachusetts Veterinary Referral Hospital (MVRH) for evaluation
teeth 209 and 210, a 1 cm 3 3–4 mm bruise on the left upper eyelid,
From the Massachusetts Veterinary Referral Hospital, Woburn, MA.
CSF, cerebrospinal fluid; IM, intramuscular; MVRH, Massachusetts
The dog was taken to a local emergency clinic for evaluation.
Correspondence: (M.T.) [email protected]
Veterinary Referral Hospital; OD, oculus dexter; OS, oculus sinister; OU, oculus uterque; PO, per os; T1WI, T1-weighted image; T2WI, T2-weighted image; TBI, traumatic brain injury; TE, echo time; TR, repetition time
114
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Iatrogenic Traumatic Brain Injury During Tooth Extraction
and severe scleral hemorrhage with exophthalmos oculus sinister
inversion recovery (TR, 7000 msec; TE, 90 msec), transverse
(OS). Neurological examination revealed an absent menace
T2*HEMO images (TR, 605 msec; TE, 23 msec), and precontrast
response oculus dexter (OD) and slow to absent pupillary light
transverse T1-weighted images (T1WI; TR, 602 msec; TE, 18 msec).
reflex oculus uterque (OU). The remainder of the neurological
IV contrast agentf (0.1 mmol/kg IV) was administered and
exam was reportedly normal. Intraocular pressures were normal
transverse (TR, 602 msec; TE, 18 msec), sagittal (TR, 412 msec;
(17–26 mm Hg OU) and fluorescein staining was negative. The dog
TE, 18 msec), and dorsal (TR, 400 msec; TE, 18 msec) postcontrast
was prescribed buprenorphine (0.018 mg/kg IV q 8 hr) for pain
T1WI images were obtained.
management. Mannitol (1 g/kg IV) was administered at the time of
The MRI (Figure 1) showed a linear tract on T2WI
admission to reduce intracranial pressure and was repeated twice
(parasagittal) extending caudodorsally from the left orbit, through
more at 4 hr intervals. Ten hours after admission, the dog was still
a skull fracture into the brain, ending in the left parietal lobe that
ataxic, but would trot for a short period of time. By 13 hr after
was consistent with intracranial penetration of the dental elevator.
admission, the dog’s ability to walk had improved significantly and
On transverse images, the tract was hyperintense and relatively well
she was falling only when changing directions suddenly. At that
defined on T2WI and poorly defined on T1WI. There was a
point in time, the emergency veterinarian started IV fluids (0.9%
hyperintense region at the dorsal extent of the tract on T2WI that
Na chloride at 7 mL/hr) for dehydration. The dog was discharged a
was hypointense on T1WI, suggestive of fluid accumulation. On
few hours later. At discharge, the dog was able to walk without
transverse T2*HEMO images, there was hypointensity in the
assistance, but was circling to the left.
ventral portion of the tract that was consistent with hemorrhage.
The patient was re-evaluated the following morning by its
There also was an area of hypointensity in each lateral ventricle,
regular veterinarian who then referred the patient to MVRH.
suggestive of intraventricular hemorrhage. The linear tract was
Physical examination revealed a normal heart rate (124 beats/min)
observed to pass through the left lateral ventricle on transverse
and respiratory rate (40 breaths/min). The dog had a bruised upper
images at the level of the thalamus, explaining the likely source of
eyelid OD, severe episcleral hemorrhage OS, a small ventral
intraventricular hemorrhage. Following administration of the IV
episcleral hemorrhage OD, and pain opening the mouth.
contrast agent, there was mild blushing contrast enhancement
Neurological examination revealed that the dog was ambulatory
along the tract. There was also a moderate amount of T2-weighted
with circling to the left and occasional falling to the right, right
hyperintense signal in the surrounding brain parenchyma that was
hemiparesis, and mild to moderate proprioceptive ataxia in all four
isointense on T1WI but that did not contrast enhance, suggestive of
limbs. There was no menace response OD, and the patient did not
cerebral edema.
track cotton balls thrown in the right visual field. The remainder of
Cerebrospinal fluid (CSF) analysis was performed and a mild
the cranial nerve examination was within normal limits. Absent
mixed-cell pleocytosis was identified. The nucleated cell count was
conscious proprioception and hopping were noted in the right
6 cells/lL (reference range, ,5 cells/lL; differential cytology: 58%
pelvic limb with delayed conscious proprioception and hopping in
nondegenerate neutrophils, 35% small to medium lymphocytes,
the right thoracic limb. Postural reactions on the left side and the
and 7% large mononuclear cells). Cytology also demonstrated the
remainder of the neurological examination were within normal
presence of red blood cells within large mononuclear cells
limits. Neuroanatomical localization was to the left forebrain
(erythrophagocytosis), suggestive of hemorrhage prior to CSF
(cerebral hemisphere/thalamus). Screening blood tests were normal
sampling.
other than elevated lactate (2.5 mmol/L; reference range, 0.3–1.8
The patient recovered normally following MRI and CSF
mmol/L). In-house prothrombin time and activated partial
sampling and was discharged the same day with clindamycing (10
thromboplastin time were within normal limits.
mg/kg PO q 12 hr). CSF aerobic and anaerobic bacterial cultures
On day 2, MRI of the head was performed using a 1.5 tesla a
b
were negative, but the clindamycin was continued because CSF
magnet . The dog was premedicated with morphine (0.3 mg/kg
bacterial culture can be negative even in the face of histologically
intramuscular [IM]) and dexmedetomidinec (0.01 mg/kg IM).
confirmed bacterial meningoencephalitis.
d
General anesthesia was induced with propofol (5 mg/kg IV),
One month after the initial MRI, the patient was re-examined
administered to effect to allow endotracheal intubation, and
at MVRH for a follow-up MRI. The owner reported that the dog
maintained with isofluranee. A routine MRI scan of the head was
was less ataxic and had started to use stairs again but still appeared
performed, including sagittal (repetition time [TR], 2900 msec;
blind in the right eye. The neurological exam was improved but still
echo time [TE], 120 msec) and transverse T2-weighted images
not normal. The patient was able to walk a straight line without
(T2WI; TR, 3000 msec; TE, 100 msec), transverse fluid-attenuated
falling but still had absent postural reactions in the right limbs and
JAAHA.ORG
115
FIGURE 1 MRI images obtained 2 days after iatrogenic traumatic brain injury during tooth extraction. Parasagittal T2-weighted (A) and
postcontrast T1-weighted (B) images show a linear tract extending from a fracture in the frontal bone (arrow), through the frontal lobe, and ending in the parietal lobe. Transverse T2-weighted (C) images at the level of the caudate nuclei show an indistinct intra-axial hyperintense tract through the brain parenchyma with surrounding cerebral edema of the left caudate nucleus and internal capsules. Transverse T2*HEMO images (D) show an area of marked hypointensity in the ventral frontal lobe consistent with hemorrhage. There is also an area of hypointensity in the left lateral ventricle consistent with intraventricular hemorrhage secondary to puncture of the left lateral ventricle (not shown). absent vision OD. Neurolocalization of the lesion was still to the
other than continued mild postural reaction deficits in the right
left forebrain. Repeat MRI showed continued presence of the linear
thoracic and pelvic limbs. MRI at that time showed continued
tract through the brain as described above, but the cerebral edema
presence of traumatic brain injury, but the lesion was smaller than
was significantly reduced. The clindamycin was discontinued and
at the time of original injury (Figure 2).
the patient was discharged. Three months later, the patient was brought in for another
Discussion
MRI. Neurologic examination revealed a normal gait and intact
Ophthalmic complications of dental disease are common in dogs
vision in both eyes. The dog still had delayed postural reactions in
and cats because of the proximity of the caudal maxillary teeth and
the right thoracic and pelvic limbs. Neurolocalization was still to
the ventral aspect of the orbit.2 Several cases of iatrogenic injury to
the left forebrain. MRI at that time showed that the tract was
periorbital structures have been reported previously, but to the
smaller than in the previous studies.
author’s knowledge, only one case of intracranial disease following
The patient was evaluated once again 1 yr after the original
tooth extraction has been reported in the veterinary literature.1 In
injury. The neurological examination was within normal limits
that case, computed tomography showed a retrobulbar abscess with
116
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Iatrogenic Traumatic Brain Injury During Tooth Extraction
FIGURE 2
MRI images obtained 1 yr after iatrogenic traumatic brain injury. The linear tract through the brain is much less obvious on
parasagittal T2-weighted images (A), but residual brain damage is visible on transverse T2-weighted (B), fluid-attenuated inversion recovery (fluid-attenuated inversion recovery; C), and postcontrast T1-weighted (D) images. There is a region of noncontrast-enhancing hypointensity lateral to the left lateral ventricle on the fluid-attenuated inversion recovery and T1-weighted images that is hyperintense on T2-weighted images. This is suggestive of brain necrosis at that location.
extension through the frontal bone into the calvaria with an
and medial pterygoid muscles.1,2 The roots of the maxillary fourth
associated intracranial abscess. The patient died 48 hr following the
premolar and both molar teeth are located within the maxillary
dental procedures despite draining the retrobulbar abscess, IV
bone in close proximity to the orbit.1–3 Periodontal pathology can
fluids, and IV antibioitics.1
weaken the bone, leading to orbital penetration during tooth
Penetration of the orbital floor during tooth extraction is
extraction.3,4 Additionally, the orbits in brachycephalic breeds are
relatively uncommon but can occur due to multifactorial causes,
positioned more rostrally than mesaticephalic and dolichocephalic
including regionally thin bony structures, periodontal pathology,
breeds, increasing the risk of iatrogenic injury to the orbit and
1
and improper extraction techniques. In dogs and cats, the bony
globe during tooth extraction.2
orbit is incomplete and the ventral aspect of the orbit is comprised
Several recommendations have been reported to reduce the
of soft tissues, including the zygomatic salivary gland, orbital fat,
risk of iatrogenic trauma to surrounding soft-tissue structures.
JAAHA.ORG
117
Dental radiographs ideally should be obtained prior to tooth extraction to help gauge the depth of the roots and to assess periodontal pathology.
1
FOOTNOTES a b
Teeth with multiple roots should be
c
sectioned prior to extraction.1,3,4 The elevator should be applied
d
with gentle and steady rotational pressure for 10–30 sec at a time
e
and advanced apically using a slow, twisting action.
1,3,4
Finally, to
help reduce the risk of accidental slippage, it is recommended that
f g
Phillips Gyroscan ACS-NT; Best, The Netherlands Morphine sulfate injection, USP; West-ward, Eatontown, NJ Dexdomitor; Zoetis, Florham Park, NJ. PropoFlo; Abbot, North Chicago, IL Fluriso; Vet One, Boise, ID Magnevist Injection; Bayer HealthCare Pharmaceuticals Inc., Wayne, NJ Clintabs; Virbac AH, Inc., Fort Worth, TX,
the elevator be held down the shaft of the instrument and a finger placed near the tip of the elevator to act as a ‘‘stop’’ should the elevator slip.
1
Conclusion Fortunately, the patient in this case report survived the iatrogenic traumatic brain injury with minimal residual neurological deficits. With attention to detail and proper handling of dental instruments, iatrogenic orbital and brain injury should remain an uncommon occurrence in veterinary medicine.
118
JAAHA
|
51:2 Mar/Apr 2015
REFERENCES 1. Smith MM, Smith EM, La Croix N, et al. Orbital penetration associated with tooth extraction. J Vet Dent 2003;20:8–17. 2. Ramsey DT, Marretta SM, Hamor RE, et al. Ophthalmic manifestations and complications of dental disease in dogs and cats. J Amer Anim Hosp Assoc 1996;32:215–24. 3. Wiggs RB, Lobprise HB. Oral surgery. In: Wiggs RB, Lobprise HB, eds. Veterinary dentistry: principles and practice. Philadelphia (PA): Lippincott-Raven; 1997:236–57. 4. Verstraete FJM. Exodontics. In: Slatter D, ed. Textbook of small animal surgery. Philadelphia (PA): Saunders; 2003:2696–709.
