Dural tear with multiple nerve root entrapment simultaneously after unstable spine injury: Intraoperative finding

Spinal cord injuries (SCIs) caused by trauma that frequently occur are dural tears and cerebrospinal fluid (CSF) leaks. They are not always detected with neuroimaging. Hence, the authors reported two cases of the dural tear with multiple nerve root entrapment after spine injury and described how managed. This case report was about two patients who had unstable spinal fractures. All patients have an asymmetrical neurological deficit. The following magnetic resonance imaging features have analyzed the presence of CSF leakage, epidural haematoma, and spine fractures. Both cases revealed intraoperative finding dural tear with multiple nerve root entrapment. We performed decompression with spinal fixation with a posterior approach, and then the patients were sent home without complication. During the follow-up period, none of the patients developed complications. The severe neurological deficit, fracture of laminar, and ligamentum flavum disruption on the MRI in patients were predictable factors in our cases.


Introduction
Spine injury is an important global health problem. Spinal cord injury causes disability, decreases the patient's quality of life, and also burdens the health system itself. The prevalence of spinal cord injury cases has increased globally from 1990 to 2016. The increase is largely related to the increasing number of traffic accidents and falls. The incidence in Southeast Asia reaches [5][6][7][8][9] cases per 100,000 population. In America, it is estimated that there are 17,000 cases per year, with the highest number of patients is male, 80%, and the average age is 42 years. 1,2 As many as 70% of spinal cord injury patients experience multiple injuries, which cause high rates of complications both in the long term and short term. 3 Spine injuries often cause damage to the dura mater. 3,4 dura mater tears are reported in 18-36% of cases of spinal cord injury. 4 The most common location for damage to the dura mater is in the thoracic spine, with an incidence of 9-36%. The high-energy trauma mechanism causes damage to the spinal canal so that it tore the dura mater. The cause can be burst injury, flexion-distraction trauma, and fracture-dislocation trauma to the spine. 3  Cerebrospinal fluid is a clear fluid produced mainly by the choroid plexus functions as a cushion or protector of the central nervous system from trauma and to nourish the central nervous system and regulate metabolic homeostasis of the central nervous system and others. 5 When there is a defect in the dura mater, it can cause cerebrospinal fluid leakage. Other complications that can occur due to leakage of cerebrospinal fluid are the formation of pseudomeningocele, dura-cutaneous fistula, meningitis, arachnoiditis, epidural abscess, and subdural hematoma. 3,6 Usually, a dural tear can be predicted preoperatively using magnetic resonance imaging (MRI). Cerebrospinal fluid leakage must be identified and managed appropriately to reduce the patient's morbidity. 3,4,6 Case report

Case 1
A 19-year-old male came with weakness on both of his legs after getting hit by a motorcycle when he crossed the road. In the emergency department, the Glasgow score was 15, systolic and diastolic blood pressures were 110/53 mmHg, and heart rate was 110 bpm. The initial examination showed bilateral leg weakness grade 1/5 on the right and grade 3/5 on the left side with sensory loss below the knee. Lower limbs reflexes were absent. There was no Babinski sign.
There were perineal anesthesia and loss of the anal sphincter tone.
Thoracic and pelvic X-rays were normal. A computed tomography (CT) scanning showed L4 vertebral burst fracture ( Figure 1A). During surgery, we found a dural tear and multiple nerve root entrapment on the right side. We performed decompression, removed huge epidural hematome, repositioned back nerve root into the thecal sac and applied double layered duroplasty, the defect with a synthetic dural patch into subdural space, after suturing DuraGen same size placed on outer duramater so dural tear fully covered (e.g., DuraGen, Integra Life Sciences Corp., USA) and fibrin glue sprayed around the margin of dural tear and performed spinal fixation ( Figure 1B and 1C). The patient's neurological deficit slowly improved, and the pain disappeared with medication during the outpatient department visit.

Case 2
A 45-year-old male came to the Neurosurgery Emergency  radiologically, are significant predictors of dura tears. 11 The severity of neurological deficit and within 24 hours are important factors to decided the urgency of spine surgery. 13,14 MRI with enhancement can find dura or subarachnoid cavity connections, the presence of pseudomeningocele. In one study, CTmyelography using intrathecal metrizamide to have been successfully used to find dura tears by observing the presence of contrast material coming out of the subarachnoid cavity. In addition, radioisotope cysternography is also useful for detecting sites of cerebrospinal fluid leakage. In addition to diagnosing dura tears, the above radiological method can also be used to diagnose cerebrospinal fluid fistulas. 9 In a study analyzing MRI of patients with spinal burst fractures, MRI findings in the form of lamina fractures more than 1 degree, interpedicular distance > 28 mm, central canal ratio < 0.46, and acute angle of the retropulse segment < 135 degrees can be used as the threshold for predicting dura tears. 13,15 Cerebrospinal fluid leakage is usually visualized directly intraoperatively as a clear fluid leak. Extensive epidural bleeding or compression of the thecal sac are the indirect signs of dural tears. Dural tears may also not be detected until the postoperative period. Clear fluid or serousanguinus indicating dural tear and fistulas that formed, usually in the period of 1-7 days postoperative. Fluctuating mass can indicate the presence of pseudomeningocele. 7 The author performed double layer duroplasty mean intradural and epidural patch to avoid CSF leakage after surgery and we used DuraGen for spinal dural tear management because it can be approximated tightly with the defects of any shape and size and additional sutures are not required. 16,17 Our cases are unique because of dural tears associated with unilateral multiple nerve root entrapment simultaneously and asymmetrical neurological deficits. We believe this to be multifactorial. We assumed that the significantly increased force from a direct flexion-extension mechanism of injury and increase intraabdominal pressure followed by disruption of the posterior spinal structure caused a substantial pressure gradient across the dura. Therefore, following laceration, the pressure gradient forced some CSF that allows multiple nerve roots entrapped. Disturbance of axonal venous flow following nerves root entrapment could damage the myelin sheath resulting in edema and nerve root dysfunction. 18,19 Conclusion Traumatic dural tear with multiple nerve root entrapment can occur simultaneously after spinal injury. Poor initial neurological status, burst type fracture and disruption of posterior structure such as ligamentum flavum and lamina fractures on the patient's neuroimaging are predictors in our cases.