Iatrogenic Spinal Cord Injury in a Trauma Patient with Ankylosing Spondylitis

Abstract

Background: The recommended practice for over 30 years has been to routinely immobilize patients with unstable cervical spinal injuries using cervical spinal collars. It is shown that patients with Ankylosing spondylitis (AS) are four times more likely to suffer a spinal fracture compared to the general population and have an eleven-fold greater risk of spinal cord injury. Current protocols of spinal immobilization were responsible for secondary neurologic deterioration in some of these patients. Objective: To describe an iatrogenic injury resulting from the use of a rigid spinal board and advocate for the use of alternative immobilization methods or no immobilization at all. Case: We present our case here of a 68-year-old male with a history of AS. The patient was ambulatory on scene after a low speed car accident, but immobilized with a rigid backboard by paramedics. He developed back pain and paraplegia suddenly when the backboard was lifted for transport to the hospital. A CT scan revealed an extension fraction of T10 to T11 with involvement of the posterior column. Emergency spinal fusion was performed. Patient died of complications in the hospital. Conclusion: This case shows that spinal immobilization should be avoided in cases of ambulatory patients without a clear indication. Alternative transport methods such as vacuum mattresses should be considered when spinal immobilization is indicated, especially for patients with predispositions to spinal injury, particularly AS, to maintain the natural alignment of the spinal curvature.

Key words::

• iatrogenic injury
• EMS, trauma
• ankylosing spondylitis
• spinal immobilization

Introduction

Ankylosing spondylitis (AS) is a seronegative spondyloarthritis that predominantly affects the axial skeleton.¹ It causes bony fusion of sacroiliac joints, ossification of supportive connective tissue structures of the spinal column, resulting in “bamboo spine” appearance, loss of lordosis of the lumbar spine, and acquired kyphosis of thoracic/cervical spine.¹ Osteoporosis and a stiff, inflexible spine increases the risk of spinal fracture in trauma even from minor mechanisms such as low speed motor vehicle collisions (MVC) and falls from standing.^2–4

Frequently, the first health care provider encounter for patients with potential spinal trauma is Emergency Medical Services (EMS). For the past 40 years, spinal immobilization with a rigid backboard has been the standard of care for patients with traumatic injuries that may involve their spine. The initial use of backboards was introduced in the 1960s after a case series was published that blamed “delayed onset paraplegia” on the “faulty handling” of patients, but only actually discussed two cases. ^5,6 Starting in the 1970s, EMS guidelines recommended the use of backboards and cervical collars for trauma patients suspected of having a spinal injury.⁶ Eventually, the practice came to include everyone who had a mechanism of injury that could cause a spine injury, regardless of their actual examination.⁶

Since their introduction, there have been multiple studies that show harm from backboards.⁶ Pain from the backboard is common and may persist even after patient removal.^6–8 The nature of the rigid backboard also causes pressure points that can develop tissue necrosis.^9,10 One patient review of admitted trauma patients found that the pressure ulcer risk was high and increased with age.¹¹ Pain from a backboard and injury may be difficult for the hospital staff to distinguish, which could lead to increased imaging.^6,12,13 In addition, being on a rigid backboard during computed tomography actually increases the radiation dose the patient receives.¹⁴ Other studies have found worsening pulmonary function with rigid backboard immobilization.^15–17 Despite these studies, patients without signs of unstable spinal fractures are routinely placed on rigid backboards with severe iatrogenic consequences sometimes occurring, such as our case report.

Case Report

A 68-year-old male with AS was the restrained driver in a low-speed MVC. The patient was a belted driver of an SUV that was struck behind by another vehicle at a low rate of speed. The patient's vehicle rolled into a chain link fence and came to a stop. There was no airbag deployment, starring of the windshield, or intrusion into the passenger compartment. The ALS paramedic team noted very minor rear end damage. The patient was ambulatory on scene. Per the EMS report he had mid lumbar pain that was chronic. He was placed in full spinal immobilization by paramedics using a cervical collar and strapping to a rigid backboard. Paramedics noted that the patient did not have any neurologic deficit prior to being placed on the backboard and immediately after being placed. During a vertical transfer on the backboard, the patient felt and heard a “pop,” with instantaneous back pain and neurological deficit in his bilateral lower extremities. The neurologic deficit occurred suddenly when the backboard was lifted according to nursing notes of the patient's description of events when he arrived in the emergency department (ED). The patient stated that since the “pop” he could not feel his legs. There was no EMS documentation of neurologic function during the ambulance ride. Documentation noted 26 minutes total from arriving at scene and arrival to the hospital. The patient was initially seen and back boarded by the local ALS/fire unit and then transported to the hospital by a private ALS unit code 2 (no lights or sirens).

The patient's chief complaint upon arrival to the ED was back pain. He stated, “I can't feel my legs.” He was alert and oriented, in no respiratory distress. He had severe tenderness without deformity to the lower thoracic spine. There was no rectal sphincter tone. There was neither sensation below the level of the umbilicus, nor any spontaneous movement in the bilateral lower extremities. Deep tendon reflexes were hypo-reflexive, and pulses were 2+.

A CT scan revealed an extension fracture of T10–T11 with involvement of the posterior column, with significant central canal compromise (Figures 1 and 2). An MRI of the spine was attempted, but the patient did not fit into the machine secondary to his spinal deformity per nursing notes. He was 64 in (163 cm) tall and weighed 113 kg (BMI 43.9). It was noted that rather than attempt the MRI surgery decided to go directly to the operating room. An emergent T10–T11 spinal fusion was performed. Following surgery, the patient had multiple complications, including persistent paraplegia and ventilator-dependent respiratory failure. He was eventually weaned off the ventilator but had complications due to C. difficile colitis and required TPN (total parenteral nutrition). He had no improvement in his neurologic function with total sensory and motor paralysis below T10. On day 26 he developed bowel perforation secondary to the C. difficile colitis. The patient declined aggressive care and he and his niece who was his power of attorney (POA) elected to make himself “Do Not Resuscitate/Do Not Intubate” and requested no new aggressive treatment but continued TPN. He was transferred to the palliative care floor. His mental status declined and his POA changed his DNR status to comfort care only, stopping the TPN. He died on post-trauma day 31.

Figure 1. Computed tomography scan showing the T10–T11 extension fracture. Note the extension and distraction of T10–T11 (arrow) and the overall abnormal curvature of the spine.

Figure 2. Computed tomography scan of spine showing posterior column involvement in the T10–T11 fracture. (a) Intrusion of the posterior column into the spinal cord canal (arrow). (b) False coloring of the spinal canal highlights the mechanism of compromise of the spinal cord by the posterior column (arrow), with resultant spinal cord damage and neurological deficit.

Discussion

Patients with AS are four times more likely to suffer a spinal fracture than the general population and have an eleven-fold greater risk of spinal cord injury.^2,3 After presentation, AS patients continue to be at higher risk for secondary neurologic deterioration, where it is estimated between 3%–25% of spinal cord injuries occur after the initial trauma, either during transit or in the early course of management.^18,19 Cervical collars and rigid backboards may force an inflexible and brittle kyphotic spine into an unnatural physiologic alignment, contributing to the creation of an unstable fracture with resultant neurologic dysfunction.^3,20 Recommended practice for over 40 years has been to routinely immobilize patients with unstable cervical spinal injuries using cervical spinal collars. There is minimal evidence to support this current protocol; in fact, it is more harmful for patients with AS. Immobilization, involving propping up the head with padding when necessary, should aim to respect this posture and may be achieved with a vacuum splint or by careful padding of all voids. The vacuum splint device, particularly when used with a cervical collar, is an effective and comfortable alternative to a rigid backboard (with or without a collar) for spinal immobilization.^19,21

In an AS case series, 15 patients with ankylosing spondylitis were followed up after sustaining spinal trauma. Twelve of the 15 patients deteriorated neurologically after presentation. Three of these had spinal epidural hematomas, two from the original injury and one from surgical intervention. Spinal immobilization protocols or extension of the ankylosed kyphotic spine during radiologic procedures were responsible for the secondary neurologic deterioration in the other patients.²² In one of the cases, during a 6-person inline transfer, the patient complained of sudden shooting pain down one side and experienced a sudden drop in blood pressure. On admission to the spinal unit he was quadriplegic.²²

Our patient was ambulatory at the scene, so he may have been able to move himself to the cot with a cervical collar in place if it was not causing undue pain. The National Association of EMS Physicians position paper on the use of long board acknowledges that the benefit to long backboards, especially in an ambulatory patient, is unproven.⁶ Their recommendation is no immobilization for patients that are alert without intoxication or distracting injuries and do not have spinal tenderness or neurologic complaints/findings.⁶ They also recommend that ambulatory patients should be placed in a cervical collar and then move themselves to the EMS cot.⁶ There have not been any patient outcome studies looking at the use of the backboard to maintain spinal precautions after extrication.⁶ Overall, more research needs to be done to see if rigid backboards actually do prevent worsening of unstable fractures versus spinal precautions.⁶ In the mean time, they recommend judicious use of immobilization in blunt trauma patients with altered level of consciousness, suspected spinal trauma, or distracting injuries.⁶ The main agreement on the usefulness of backboards is the use in spinal precautions during transfer, especially when the patient must be moved by multiple providers from the position of injury.⁶ However, rigid backboards are not necessary as vacuum splints can be used and do not have the same risks as backboards.⁶ When on the ambulance cot with a cervical collar and secure straps, the backboard does not add any benefit to the spinal precautions protocols.⁶

Our case illustrates the need for great care when handling trauma patients with predispositions to spinal injuries, such as patients with AS. There is minimal evidence that placing patients on backboards actually decrease spinal motion compared to being strapped to an EMS cot.⁶ Cadaver studies also show significant spinal movement with transfers to and from the backboard.^23–26 Ambulatory patients with AS should be asked to self transport to the cot with a cervical collar in place if it does not increase their pain. AS patients should receive full body support to maintain alignment of their native spinal curvature and should not be forced into the supine position. Attempting to immobilize trauma victims with AS using only rigid cervical collars and backboards may be deleterious for this special population, even if an unstable spinal fracture is suspected. Studies have shown that vacuum mattresses are more effective at maintaining a natural spinal curve due to their adaptability to the individual's neutral position as well as being more comfortable.²⁷ Given the uncertain benefit and known risks of spinal immobilization, all efforts should be done to avoid it in patients with AS and instead the focus should be on spinal precautions. However, it may be difficult to adapt these changes in the prehospital setting due to a lack of resources, diversity in healthcare provider training and skill sets, and differences in local transport protocols. EMS providers can be trained however to apply criteria to clear patients of the need for spinal immobilization and use judicial use of rigid backboards.^6,28

Conclusion

Spinal fractures with subsequent neurological deficits contribute to the increased morbidity and mortality of AS trauma patients. Our patient did not have any paraplegia until after spinal immobilization. Rigid backboards are harmful to this patient population and efforts should be made to prevent their use. Backboards and immobilization should not be used in low risk ambulatory patients. Future research on rigid backboards should be done to determine if their general use should continue at all.