Clinical treatment of traumatic brain injury complicated by cranial nerve injury

Endoscopic transorbital decompression for traumatic superior orbital fissure syndrome: from cadaveric study to clinical application

PURPOSE

The endoscopic endonasal approach (EEA) is a minimally invasive and promising modality for treating traumatic superior orbital fissure (SOF) syndrome (tSOFS). Recently, the endoscopic transorbital approach (ETOA) has been considered an alternative method for reaching the anterolateral skull base. This study accessed the practicality of using the ETOA to treat SOF decompression using both cadaveric dissection and clinical application.

METHODS

Bilateral anatomic dissections were performed on four adult cadaveric heads using the ETOA and EEA to address SOF decompression. The ETOA procedure for SOF decompression is described, and the extent of SOF decompression was compared between the ETOA and EEA. The clinical feasibility of the ETOA for treating SOF decompression was performed in two patients diagnosed with tSOFS.

RESULTS

ETOA allowed for decompression over the lateral aspect of the SOF, from the meningo-orbital band superolaterally to the maxillary strut inferomedially. By contrast, the EEA allowed for decompression over the medial aspect of the SOF, from the lateral opticocarotid recess superiorly to the maxillary strut inferiorly. In both patients treated using the ETOA and SOF decompression, the severity of ophthalmoplegia got obvious improvement.

CONCLUSIONS

Based on the cadaveric findings, ETOA provided a feasible access pathway for SOF decompression with reliable outcomes, and our patients confirmed the clinical efficacy of the ETOA for managing tSOFS.

Characteristics of ocular injuries associated with mortality in patients admitted with major trauma

BACKGROUND

Few ocular trauma studies have addressed mortality outcomes. We sought to determine characteristics of mortality-related ocular trauma admissions and compared them with non-fatal injuries.

METHODS

A retrospective study was conducted using de-identified data of patients admitted with major trauma from the National Trauma Data Bank (2008-2014). Patients with ocular injury were identified using ICD- 9CM codes. Demographics, intention and mechanism, types of ocular and head injuries, and injury severity were documented. Mortality was determined using post-admission disposition. Statistical analysis using student t-test, chi-square, and odds ratios (OR) calculations were performed with STATA-17 software. Significance was set at P < 0.05.

RESULTS

Of 316,485 patients admitted with ocular trauma, 12,233 (3.86%) were mortality related. Expired patients were older than survivors: mean (SD) of 50.1(25.5) vs. 41.5(22.8) years. White (OR = 1.32; P < 0.001), ≥ 65years old (OR = 2.25; P < 0.001), and male (OR = 1.05; P = 0.029) patients were most likely to expire than their counterparts. Common mechanisms of injury in survivors were falls (25.3%), motor vehicle traffic-occupant, MVTO (21.8%) and struck by/against (18.1%) and for fatal injuries, falls (29.7%), MVTO (21.9%) and firearms (11.5%). Traumatic brain injury (TBI) was documented in 88.2% of mortality-related admissions. Very severe injury severity scores (ISS > 24) (OR = 19.19; P < 0.001) and severe Glasgow Coma Score (GCS < 8) (OR = 19.22; P < 0.001) were most associated with mortality than survival. Firearms were most associated with very severe ISS (OR = 3.73; P < 0.001), severe GCS (OR = 4.68; P < 0.001) and mortality (OR = 5.21; P < 0.001) than other mechanisms. Patients with cut/pierce injuries had the greatest odds of survival (OR = 13.48; P < 0.001). Optic nerve/visual pathways injuries (3.1%) had the highest association with very severe ISS (OR = 2.51; P < 0.001), severe GCS (OR = 3.64; P < 0.001) and mortality (OR = 2.58; P < 0.001) than other ocular injuries. Black patients with very severe ISS (OR = 32.14; P < 0.001) and severe GCS (OR = 31.89; P < 0.001) were more likely to expire than other race/ethnicities with similar injury severity.

CONCLUSIONS

Mortality-related admissions were older, male, and mostly of White race than ocular trauma admissions of survivors. Firearms were the deadliest mechanism. TBI was commonly associated and patients with optic nerve/pathway injuries, very severe ISS and severe GCS had higher mortality rates. Characteristics and demographic variations identified in this study may be useful in developing focused measures aimed at preventing trauma-related deaths.

Traumatic cavernous sinus syndrome - A peculiar presentation of multiple cranial nerve neuropathies following a minor head injury: Case report and literature review

BACKGROUND

In patients with traumatic head injuries, the percentage of cranial nerve injuries (CNI) range from4.3 to 17.6% in which majority are isolated CNI[1-5].In present literature, moderate to severe types of head injuries are often studied which may result in a lack of representation and description of CNI associated with minor head injuries (MHI). Alongside this peculiar case of a traumatic cavernous sinus syndrome (CSS) that is non-thrombotic and non-fistulous in nature, this paper aims to analyse traumatic CNI in non-severe head injuries and the surrounding literature.

CASE REPORT

A 65-year-old man who had sustained a minor head injury was found to have CNI of III, IV and VI.Brain imaging showed scattered traumatic subarachnoid haemorrhage and a non-displaced right zygomatic arch fracture. Despite the short course of high dose dexamethasone, he showed only partial recovery of his CNI after one year.

CONCLUSION

We present a case of traumatic CSS likely secondary to tractional injury from a MHI. Injury to the extraocular nerves wasfound to be one of the more commonly observed combination of CNI from the literature review conducted. In patients with MHI, multiple CNI is less common. Hence, consideration should be given to work upfor secondary causes such as tumours. There is presently no known clear identifiable pattern of CNI associated with MHI. CT brain findings of skull base fractures and early onset of cranial nerve palsies are generally associated with worse outcomes. More remains to be studied about tractional CNI in non-severe head injuries.

Incidence and Characteristics of Cranial Nerve Injuries: A Nationwide Observational Study in Japan

Background: Large-scale data on cranial nerve injuries are scarce. Methods: This study enrolled 361,706 patients registered in the Japanese Trauma Data Bank from 2004 to 2018. We selected patients with cranial nerve injury using the corresponding Abbreviated Injury Scale codes and examined the incidence and characteristics. Results: In total, 347,101 patients were eligible for inclusion in our analysis. By mechanism of trauma, all cranial nerve injuries occurred in <1% of registered cases. The highest incidence was 0.2190% (55/25,117) for facial nerve injury in bicycle crash. By cause of trauma, all cranial nerve injuries occurred in <1% of registered cases. The highest incidence was 0.1943% (37/19,044) for facial nerve injury in occupational injury. No patients with spinal accessory nerve injury were observed. The most common cranial nerve injury was to the facial nerve (n = 278). Most cranial nerve injury patients are in the 30s to 50s age range, and there was a male predominance. Multiple cranial nerve injuries were observed in 81 patients. Many cranial nerve injury cases are complicated by skull base fractures. Conclusions: We revealed the incidence and characteristics of cranial nerve injury. Our findings may help physicians detect these injuries at an early stage in patients at risk.

Cranial nerve injuries in patients with moderate to severe head trauma - Analysis of 91,196 patients from the TraumaRegister DGU® between 2008 and 2017

OBJECTIVE

Traumatic brain injury (TBI) constitutes a major cause of trauma-related disability and mortality. The epidemiology and implications of associated cranial nerve injuries　(CNI)　in moderate to severe TBI are largely unknown. We aimed to determine the incidence of CNI in a large European cohort of TBI patients as well as clinical differences between TBI cases with and without concomitant CNI (CNI vs. control group) by means of a multinational trauma registry.

METHODS

The TraumaRegister DGU® was evaluated for trauma patients with head injuries ≥ 2 Abbreviated Injury Scale, who had to be treated on intensive care units after emergency admission to European hospitals between 2008 and 2017. CNI and control cases were compared with respect to demographic, clinical, and outcome variables.

RESULTS

1.0% (946 of 91,196) of TBI patients presented with additional CNI. On average, CNI patients were younger than control cases (44.3 ± 20.6 vs. 51.8 ± 23.0 years) but did not differ regarding sex distribution (CNI 69.4% males vs. control 69.1%). Traffic accidents were encountered more frequently in CNI cases (52.3% vs. 46.7%; p < 0.001; chi-squared test) and falls more commonly in the control group (45.2% vs. 37.1%; p < 0.001). CNI patients suffered more frequently from concomitant face injuries (28.2% vs. 17.5%; p < 0.001) and skull base fractures (51.0% vs. 23.5%; p < 0.001). Despite similar mean Injury Severity Score (CNI 21.8 ± 11.3; control 21.1 ± 11.7) and Glasgow Coma Scale score (CNI 10.9 ± 4.2, control 11.1 ± 4.4), there was a considerably higher proportion of anisocoria in CNI patients (20.1% vs. 11.2%; p < 0.001). Following primary treatment, 50.8% of CNI and 35.5% of control cases showed moderate to severe disability (Glasgow Outcome Scale score 3-4; p < 0.001).

CONCLUSION

CNI rarely occur in the context of TBI. When present, they indicate a higher likelihood of functional impairment following primary care and complicating skull base fractures should be suspected.

Craniocervical fractures management in case of craniocervical pneumatization: case report and review of the literature

INTRODUCTION

Extensive craniocervical pneumatization (CCP) refers to an abnormal pneumatization extended from the temporal bone into adjacent bone structures, especially the skull base and the craniocervical junction. The etiology remains controversial; however several studies reported a correlation with recurrent Valsalva maneuvers or Eustachian tube dysfunction. Although some cases requiring surgical treatment have been reported, conservative treatment remains the gold standard. The authors aimed to describe a case of CCP, complicated by a spontaneous fracture of a pneumatized left occipital condyle. Furthermore, they reviewed all previously reported cases of fractures in CCP in order to propose a standardized approach to this pathology.

METHODS

A total of 148 studies were retrieved. Of those, 23 studies (including 26 patients in addition to our case) were included in the review. These studies consisted of case reports or small case series (up to 3 patients).

RESULTS

In 3 patients (11.1%), bone pneumatization involved C0; all remaining patients had both C0 and C1 pneumatization, while in 7 cases (25.9%), an extension to C2 and/or C3 was reported. Radiological follow-up was performed in 20 patients (74.1%), showing in all of the cases either stability (6 patients, 22.2%), improvement, or complete resolution (6 patients, 22.2% vs 8 patients, 29.7%). Two patients underwent surgical intervention.

CONCLUSIONS

This review suggests that fractures secondary to CCP are extremely rare and are associated to a good clinical and radiological outcome with conservative treatment. Ear, nose, and throat (ENT) evaluation is recommended to detect cases who need treatment for a subjacent middle ear disease.

CT of Skull Base Fractures: Classification Systems, Complications, and Management

As advances in prehospital and early hospital care improve survival of the head-injured patient, radiologists are increasingly charged with understanding the myriad skull base fracture management implications conferred by CT. Successfully parlaying knowledge of skull base anatomy and fracture patterns into precise actionable clinical recommendations is a challenging task. The authors aim to provide a pragmatic overview of CT for skull base fractures within the broader context of diagnostic and treatment planning algorithms. Laterobasal, frontobasal, and posterior basal fracture patterns are emphasized. CT often plays a complementary, supportive, or confirmatory role in management of skull base fractures in conjunction with results of physical examination, laboratory testing, and neurosensory evaluation. CT provides prognostic information about short- and long-term risk of cerebrospinal fluid (CSF) leak, encephalocele, meningitis, facial nerve paralysis, hearing and vision loss, cholesteatoma, vascular injuries, and various cranial nerve palsies and syndromes. The radiologist should leverage understanding of specific strengths and limitations of CT to anticipate next steps in the skull base fracture management plan. Additional imaging is warranted to clarify ambiguity (particularly for potential sources of CSF leak); in other cases, clinical and CT criteria alone are sufficient to determine the need for intervention and the choice of surgical approach. The radiologist should be able to envision stepping into a multidisciplinary planning discussion and engaging neurotologists, neuro-ophthalmologists, neurosurgeons, neurointerventionalists, and facial reconstructive surgeons to help synthesize an optimal management plan after reviewing the skull base CT findings at hand. Online supplemental material is available for this article. ^©RSNA, 2021.

A Prospective Study on the Incidence and Outcome of Cranial Nerve Injuries in Patients with Traumatic Brain Injuries

Background Posttraumatic cranial nerve injuries are not uncommon and can occur by shearing forces, rapid acceleration/deceleration, or injury to the skull base. The incidence of cranial nerve injury in craniocerebral trauma varies between 5 and 23 percent in various literature.

Methodology A prospective study was conducted on the incidence and outcome of cranial nerve injuries (CNI) in 256 consecutive cases of traumatic brain injuries (TBI). Patients over the age of 5 years with a follow-up of 6 months in the period from September 2017 to November 2018 in our institution were sampled.

Results A total of 256 patients were included in our study. The incidence of CNI in TBI patients was 14.8% (38 patients). Facial nerve was the most common cranial nerve to be involved, followed by olfactory nerve and vestibulocochlear nerve. Cranial nerve injury was more common in patients with severe head injury (p < 0.005), younger age group, associated base of skull fractures (p < 0.001), and facial fractures (p < 0.005). Twenty-eight patients (73.7%) had a delayed presentation of CNI (p < 0.001). Of the 73.6% patients who recovered, 16 (42%) patients had partial recovery, while 12 (31%) patients had complete recovery. Younger age group (p < 0.05) and delayed onset of deficit (p < 0.001) were associated with significant better outcome.

Conclusions CNI are a major cause of morbidity in TBI patients. All patients admitted with TBI should be examined meticulously for CNI on follow-up.

Sex and age differences in hospitalized pediatric traumatic brain injury

BACKGROUND

The aim of this study was to investigate the epidemiological characteristics of pediatric traumatic brain injury (TBI) requiring hospitalization in Chinese children ≤17 years of age according to sex and age group.

METHODS

This study retrospectively analyzed pediatric TBI inpatient data obtained via electronic health records from one children's hospital in China. Patients aged ≤17 years admitted to the hospital due to TBI between 1 January 2013 and 31 December 2015 were identified using International Classification of Diseases (ICD) -9 and ICD-10 codes. The demographic, injury, and hospitalization characteristics were analyzed by sex and age groups.

RESULTS

The subject consisted of 1,087 pediatric TBI patients admitted to the hospital (61.5% boys). The highest proportion of hospitalization was observed in the 1-3 years age group. For both boys and girls, the most common diagnosis was "traumatic epidural hematoma" and the leading mechanism of TBI was "fall". The median length of hospital stay was 8.5 days and the median hospitalization cost was 7,977.4 Chinese yuan (approximately $US 1,140).

CONCLUSIONS

Boys and children aged 1-3 years incurred more pediatric TBI requiring hospitalization than their counterparts. Prevention of falls, the most common injury mechanism in both boys and girls, is an important strategy to reduce pediatric TBI and related hospitalizations.

Amelioration of visual deficits and visual system pathology after mild TBI with the cannabinoid type-2 receptor inverse agonist SMM-189

Mild TBI is often accompanied by visual system dysfunction and injury, which is at least partly caused by microglial neuroinflammatory processes initiated by the injury. Using our focal cranial blast mouse model of closed-skull mild TBI, we evaluated the ability of the cannabinoid type-2 (CB2) receptor inverse agonist SMM-189, which biases microglia from the harmful M1 state to the beneficial M2 state, to mitigate visual system dysfunction and injury after TBI. Male C57BL/6 or Thy1-EYFP reporter mice received a closed-head blast of either 0-psi (sham) or 50-psi to the left side of the cranium. Blast mice received vehicle or 6 mg/kg SMM-189 daily beginning 2 h after blast. Sham mice received vehicle. In some mice, retina and optic nerve/tract were assessed morphologically at 3-7 days after blast, while other mice were assessed functionally by Optomotry 30 days after blast and morphologically at ≥30 days after blast. Mice sacrificed at 3-7 days were treated daily until sacrificed, while those assessed ≥30 days after blast were treated daily for 2 weeks post blast. Axon damage was evident in the left optic nerve and its continuation as the right optic tract at 3 days post blast in vehicle-treated blast mice in the form of swollen axon bulbs, and was accompanied by a significant increase in the abundance of microglia. Testing at 30 days post blast revealed that the contrast sensitivity function was significantly reduced in both eyes in vehicle-treated blast mice compared to vehicle-treated sham blast mice, and axon counts at ≥30 days after blast revealed a ∼10% loss in left optic nerve in vehicle-treated blast mice. Left optic nerve axon loss was highly correlated with the left eye deficit in contrast sensitivity. Immunolabeling at 30 days post blast showed a significant increase in the abundance of microglia in the retinas of both eyes and in GFAP + Müller cell processes traversing the inner plexiform layer in the left eye of vehicle-treated blast mice. SMM-189 treatment reduced axon injury and microglial abundance at 3 days, and mitigated axon loss, contrast sensitivity deficits, microglial abundance, and Müller cell GFAP upregulation at ≥30 days after blast injury. Analysis of right optic tract microglia at 3 days post blast for M1 versus M2 markers revealed that SMM-189 biased microglia toward the M2 state, with this action of SMM-189 being linked to reduced axonal injury. Taken together, our results show that focal left side cranial blast resulted in impaired contrast sensitivity and retinal pathology bilaterally and optic nerve loss ipsilaterally. The novel cannabinoid drug SMM-189 significantly mitigated the functional deficit and the associated pathologies. Our findings suggest the value of combatting visual system injury after TBI by using CB2 inverse agonists such as SMM-189, which appear to target microglia and bias them away from the pro-inflammatory M1 state, toward the protective M2 state.

Posttraumatic olfactory dysfunction

Impairment of smell may occur following injury to any portion of the olfactory tract, from nasal cavity to brain. A thorough understanding of the anatomy and pathophysiology combined with comprehensively obtained history, physical exam, olfactory testing, and neuroimaging may help to identify the mechanism of dysfunction and suggest possible treatments. Although most olfactory deficits are neuronal mediated and therefore currently unable to be corrected, promising technology may provide novel treatment options for those most affected. Until that day, patient counseling with compensatory strategies and reassurance is essential for the maintenance of safety and QoL in this unique and challenging patient population.

Disorders of the lower cranial nerves

Lesions of the lower cranial nerves (LCN) are due to numerous causes, which need to be differentiated to optimize management and outcome. This review aims at summarizing and discussing diseases affecting LCN. Review of publications dealing with disorders of the LCN in humans. Affection of multiple LCN is much more frequent than the affection of a single LCN. LCN may be affected solely or together with more proximal cranial nerves, with central nervous system disease, or with nonneurological disorders. LCN lesions have to be suspected if there are typical symptoms or signs attributable to a LCN. Causes of LCN lesions can be classified as genetic, vascular, traumatic, iatrogenic, infectious, immunologic, metabolic, nutritional, degenerative, or neoplastic. Treatment of LCN lesions depends on the underlying cause. An effective treatment is available in the majority of the cases, but a prerequisite for complete recovery is the prompt and correct diagnosis. LCN lesions need to be considered in case of disturbed speech, swallowing, coughing, deglutition, sensory functions, taste, or autonomic functions, neuralgic pain, dysphagia, head, pharyngeal, or neck pain, cardiac or gastrointestinal compromise, or weakness of the trapezius, sternocleidomastoid, or the tongue muscles. To correctly assess manifestations of LCN lesions, precise knowledge of the anatomy and physiology of the area is required.

Defining pediatric traumatic brain injury using International Classification of Diseases Version 10 Codes: a systematic review

BACKGROUND

Although healthcare administrative data are commonly used for traumatic brain injury (TBI) research, there is currently no consensus or consistency on the International Classification of Diseases Version 10 (ICD-10) codes used to define TBI among children and youth internationally. This study systematically reviewed the literature to explore the range of ICD-10 codes that are used to define TBI in this population. The identification of the range of ICD-10 codes to define this population in administrative data is crucial, as it has implications for policy, resource allocation, planning of healthcare services, and prevention strategies.

METHODS

The databases MEDLINE, MEDLINE In-Process, Embase, PsychINFO, CINAHL, SPORTDiscus, and Cochrane Database of Systematic Reviews were systematically searched. Grey literature was searched using Grey Matters and Google. Reference lists of included articles were also searched for relevant studies. Two reviewers independently screened all titles and abstracts using pre-defined inclusion and exclusion criteria. A full text screen was conducted on articles that met the first screen inclusion criteria. All full text articles that met the pre-defined inclusion criteria were included for analysis in this systematic review.

RESULTS

A total of 1,326 publications were identified through the predetermined search strategy and 32 articles/reports met all eligibility criteria for inclusion in this review. Five articles specifically examined children and youth aged 19 years or under with TBI. ICD-10 case definitions ranged from the broad injuries to the head codes (ICD-10 S00 to S09) to concussion only (S06.0). There was overwhelming consensus on the inclusion of ICD-10 code S06, intracranial injury, while codes S00 (superficial injury of the head), S03 (dislocation, sprain, and strain of joints and ligaments of head), and S05 (injury of eye and orbit) were only used by articles that examined head injury, none of which specifically examined children and youth.

CONCLUSION

This review provides evidence for discussion on how best to use ICD codes for different goals. This is an important first step in reaching an appropriate definition and can inform future work on reaching consensus on the ICD-10 codes to define TBI for this vulnerable population.

Utility of surveillance imaging after minor blunt head trauma

OBJECT

Nonoperative blunt head trauma is a common reason for admission in a pediatric hospital. Adverse events, such as growing skull fracture, are rare, and the incidence of such morbidity is not known. As a result, optimal follow-up care is not clear.

METHODS

Patients admitted after minor blunt head trauma between May 1, 2009, and April 30, 2013, were identified at a single institution. Demographic, socioeconomic, and clinical characteristics were retrieved from administrative and outpatient databases. Clinical events within the 180-day period following discharge were reviewed and analyzed. These events included emergency department (ED) visits, need for surgical procedures, clinic visits, and surveillance imaging utilization. Associations among these clinical events and potential contributing factors were analyzed using appropriate statistical methods.

RESULTS

There were 937 admissions for minor blunt head trauma in the 4-year period. Patients who required surgical interventions during the index admission were excluded. The average age of the admitted patients was 5.53 years, and the average length of stay was 1.7 days; 15.7% of patients were admitted for concussion symptoms with negative imaging findings, and 26.4% of patients suffered a skull fracture without intracranial injury. Patients presented with subdural, subarachnoid, or intraventricular hemorrhage in 11.6%, 9.19%, and 0.53% of cases, respectively. After discharge, 672 patients returned for at least 1 follow-up clinic visit (71.7%), and surveillance imaging was obtained at the time of the visit in 343 instances. The number of adverse events was small and consisted of 34 ED visits and 3 surgeries. Some of the ED visits could have been prevented with better discharge instructions, but none of the surgery was preventable. Furthermore, the pattern of postinjury surveillance imaging utilization correlated with physician identity but not with injury severity. Because the number of adverse events was small, surveillance imaging could not be shown to positively influence outcomes.

CONCLUSIONS

Adverse events after nonoperative mild traumatic injury are rare. The routine use of postinjury surveillance imaging remains controversial, but these data suggest that such imaging does not effectively identify those who require operative intervention.

Endoscopic transmaxillary transMüller's muscle approach for decompression of superior orbital fissure: a cadaveric study with illustrative case

BACKGROUND

In an effort to avoid the damage and inconvenience associated with transcranial approaches, we developed an endoscopic transmaxillary transMüller's muscle approach for decompression of the superior orbital fissure (SOF).

METHODS

The endoscopic transmaxillary transMüller's muscle route was performed in ten cadaveric heads. We measured important anatomic landmarks, and angles radiographically. This approach was initially attempted in one patient with traumatic superior orbital fissure syndrome (tSOFS).

RESULTS

A maxillary antrostomy was carried out with a buccal sulcus incision. The sinus ostium and the course of infraorbital nerve were used as endoscopic anatomic landmarks. Then the inferior orbital fissure was drilled out, followed by separating the Müller's muscle. The periorbita were peeled off from the lateral wall, followed by the endoscope going along the periorbital space, until the lateral aspect of the SOF could be visualized. Decompression was successfully performed in all specimens. The initial clinical application justified this approach. The patient had an uneventful postoperative course and satisfactory recovery.

CONCLUSION

This approach offers sufficient endoscopic visualization and reliable decompression of SOF. It avoids the need for brain retraction, temporalis muscle manipulation, or any external incision, and appears to be able to deliver satisfying aesthetic results as well as favourable functional recovery.

Clinical features and functional recovery of traumatic isolated oculomotor nerve palsy in mild head injury with sphenoid fracture

OBJECT

The aim of this study was to provide information about long-term functional outcome in patients with isolated oculomotor nerve palsy following minor head injury and to discuss surgical treatment of these patients, especially those with accompanying sphenoid fracture.

METHODS

A retrospective analysis was made of 26 patients with traumatic isolated oculomotor nerve palsy. The severity of oculomotor nerve palsy and the functional recovery were evaluated based on extraocular muscle movement, eyelid movement, and pupil size. On average, patients were evaluated 3.6 days after the initial injury, and the average follow-up period was 14.2 months (range 3 months-2 years).

RESULTS

Twenty men and six women were enrolled in this study. The most common cause of trauma was motor vehicle accident in 17 (65.4%) of 26. Among all the recorded symptoms, internal ophthalmoplegia was most frequently seen. The recovery rates of ptosis, external ophthalmoplegia, and internal ophthalmoplegia were 95% (19 of 20 patients), 83.3% (15 of 18 patients), and 50% (13 of 26 patients), respectively. The 6 patients with sphenoid fracture underwent surgical decompression of the superior orbital fissure, after which all patients experienced recovery from ptosis and external ophthalmoplegia and 66.7% (4 of 6 patients) recovered from internal ophthalmoplegia.

CONCLUSIONS

Limited eye movement may be a major factor that negatively affects functional recovery after mild head injury. Sphenoid fracture might be one of the potential mechanisms involved in traumatic isolated oculomotor nerve palsy after mild head injury. Surgical decompression should be considered when there is evidence of bone compression of the superior orbital fissure.

Isolated trochlear nerve palsy with perimesencephalic subarachnoid haemorrhage

Perimesencephalic subarachnoid haemorrhage is usually asymptomatic other than meningeal irritation sign. The authors report a case of subarachnoid haemorrhage at the quadrigeminal cistern showing ipsilateral trochlear nerve palsy and discuss the pathogenesis. A 71-year-old man with a history of diabetes mellitus and acute myocardial infarction presented with diplopia. He underwent CT, which revealed subarachnoid haemorrhage at the left quadrigeminal cistern. Neurological examination revealed left isolated trochlear nerve palsy, with results otherwise normal. The diagnosis of perimesencephalic subarachnoid haemorrhage was established on neuroimaging. The amount of haemorrhage is related to symptoms. A dense clot in the quadrigeminal cistern might have been the cause of trochlear nerve palsy.