Complete spinal cord injury from postoperative seroma following scoliosis surgery: A case report with favorable ambulatory outcomes after comprehensive rehabilitation

Context: Postoperative seroma is a known complication following spine deformity surgery. However, complete spinal cord injury (SCI) due to postoperative seroma is rare. Rehabilitation strategies and outcomes of SCI associated with postoperative seroma have been inadequately described. Findings: A 15-year-old female experienced inadvertent durotomy during pinal deformity correction surgery for idiopathic adolescent scoliosis. Despite immediate decompressive laminectomy, she developed complete loss of motor and sensory function with neurological level of injury at T10 immediately following the surgery. Urgent magnetic resonance imaging revealed cord compression due to seroma. Decompressive surgery was performed 48 h later and timely intensive rehabilitation was provided for 3 months, which included the use of robotic-assisted gait training (RAGT) to maximize neurological recovery. She demonstrated impressive improvement from grade A to D on the American Spinal Injury Association Impairment Scale and regained functional ambulation over the 3-month period. We describe a comprehensive rehabilitation program to manage SCI associated with postoperative seroma, entailing the use of a robotic gait device for locomotor training. The progression of the patient’s neurological status and functional outcomes was documented accordingly. Conclusion/clinical relevance: Complete SCI due to seroma, a surgical complication of corrective scoliosis surgery, is rare. However, prompt postoperative examination should be performed routinely in anticipation of neurological deterioration. Early rehabilitation comprising of gait re-training and the use of RAGT might enhance the lower-limb motor strength and functional recovery.


Introduction
Spinal cord injury (SCI) following surgical correction of adolescent idiopathic scoliosis is rare, with an incidence of 0.12-0.59%. [1][2][3] Despite numerous reports of SCI following correction surgery, the clinical course and neurological progress in these patients are inadequately described. 3, 4 We report a case of a 15-year-old female with idiopathic scoliosis who required corrective spinal surgery and developed a complete SCI from spinal seroma. A structured rehabilitation program was provided including the use of robotic-assisted gait training (RAGT) (Lokomat®, Hocoma, Switzerland) for locomotor training. After 3 months of inpatient rehabilitation, the patient demonstrated impressive improvement and regained functional walking. To the best of our knowledge, this is the first case report describing the neurological and functional outcomes of complete SCI associated with postoperative seroma. A 15-year-old female with Marfan syndrome was diagnosed with idiopathic scoliosis at a young age, but remained fully independent for ambulation. Her follow-up radiograph revealed a Cobb angle of 45°in the thoracolumbar region. Following counseling, she consented to posterior instrumentation and correction of scoliosis with facet osteotomies and spinal fusion from T4 to L4. Intraoperatively, inadverdent durotomy occurred during facet osteotomy of right T7-T8. Motor evoked potentials (MEPs) were monitored intraoperatively and were subsequently found to be absent in bilateral lower limbs. Decompressive laminectomy was performed from T4 to T9, but there was no restoration of MEPs. Immediately after the surgery, she experienced complete loss of strength and sensation in both lower limbs with a neurological level of injury at T10 without sacral sparing. She was classified as T10 grade A on the American Spinal Injury Association (ASIA) impairment scale (AIS) according to the International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI). 5 Urgent spine magnetic resonance imaging (MRI) revealed posterior epidural fluid collection from T1 to T10, with consequent anterior displacement of the spinal cord from T4 to T7 (Appendix figure 1). Decompressive laminectomy from T4 to T9 and removal of the left T5 and L2 screws were performed 48 h after the first surgery (Appendix figure 2). Daily ISNCSCI monitoring was instituted following the surgery, although the injury remained complete. Transcranial magnetic stimulation and evaluation of tibial nerve somatosensory evoked potential performed 2 weeks after the surgery indicated persistent bidirectional corticospinal disruption.

Case description
She underwent physiotherapy within the first week after the surgery and was transferred to a rehabilitation unit in the third week. At this juncture, she had recovered some sensation and was upgraded to AIS grade B. She was treated by a multidisciplinary rehabilitation team comprising of physiatrists, physiotherapists, occupational therapists, rehabilitation specialty nurses, dietitians, and medical social workers. Her impairments included paraplegia, sensory impairment at and below T10, urinary retention, lower limb spasticity, and orthostatic hypotension. Her physical therapy entailed twicedaily sessions of physiotherapy and daily occupational therapy during weekdays, lasting 45-60 min each. The therapy sessions included range-of-motion exercises, dynamic sitting, and transfer training. Lower limb spasticity was treated with oral baclofen and botulinum toxin injection. She exhibited return of motor function on day 5 after admission to the rehabilitation unit (day 30 after the injury) and her bilateral lower limb strength gradually improved (Table 1). RAGT was provided as an adjunct to conventional gait training, since the patient could tolerate high-intensity overground mobilization and was a suitable candidate with no contraindications (Appendix figure 3). The aim of this therapy was to provide repetitive task-specific training to improve locomotion. RAGT was provided 5 times per week for 10 sessions from week 9 to week 10 after the injury. The settings of Lokomat® were as follows: duration of 20-30 min per session, gait speed of 1.0 km/h, minimum body weight support set at 53% on an average, and guidance force set at 90-100%.
After 12 weeks of inpatient rehabilitation, her impairment status progressed to AIS D and she was able to ambulate for more than 50 meters with a walking frame. Her functional status assessed using the Functional Independence Measure and Walking Index for Spinal Cord Injury II also improved significantly (Table 1). 6,7 Repeated MRI scans of the thoracic spine at 8 weeks after the injury revealed a reduction in the size of the epidural fluid collection.

Discussion and conclusion
We described a rare case of complete SCI resulting from postoperative seroma following a spinal deformity correction surgery. Significant neurological improvement, which translated into ambulatory outcomes, was achieved after inpatient rehabilitation.
Postoperative seroma is a known complication of surgeries for the correction of spinal deformities. However, it does not commonly result in neurological deficits. 8,9 The exact incidence has not been established due to its rarity and only one case has been reported previously. 10 Cochrane et al. described a case of a 71year-old male who developed posterior cord syndrome from a postoperative seroma at 3 days after cervical instrumentation surgery. 10 The patient achieved good functional outcomes following a 5-week rehabilitation program. In contrast, the patient in the present case exhibited complete loss of sensorimotor control immediately after the surgery. The differences in clinical presentations of these two cases highlight the necessity of routine postoperative neurological examination. ISNCSCI is a suitable standardized tool for such examinations. Regular monitoring of neurological progress after spinal surgery should be practiced, since SCI may develop gradually.
ISNCSCI is widely used as a prognostic tool to predict long-term prognosis in SCI, with the availability of robust literature in the form of observational studies and databases. [11][12][13][14][15] Thoracic SCI has worse prognosis compared to other spinal levels of injury such as injuries in the cervical and thoracolumbar regions. 16 Patients with traumatic thoracic SCI recover by at least one  12 Despite these findings, the prognosis of iatrogenic complete SCI has not been studied comprehensively and only a case series with diverse functional outcomes has been described. 1 Specifically, one patient had complete regression of her paraplegia after rehabilitation, while the other two patients remained in complete tetraplegia and paraplegia, respectively. 1 Our patient demonstrated significant neurological recovery from AIS A to D and functional walking was achieved over a period of 3 months. Several factors contributed to her favorable outcomes. Early detection of SCI followed by early decompressive surgery played an important role. The return of motor and sensory function could represent natural recovery from spinal shock and resolution of cord edema. The term "spinal shock" was introduced more than 150 years ago to describe complete loss of motor and sensory functions below the level of the lesion and loss of muscle tone and tendon reflexes following acute SCI. 18 It has been hypothesized that spinal shock occurs from withdrawal of supraspinal facilitation and increased segmental inhibition, although the exact mechanism remains unclear s . Spinal shock usually lasts for days or weeks, 19 which is consistent with the presentation in our case. Moreover, spontaneous recovery from resolution of spinal cord edema may contribute to neurological improvement. A 3-month course of an inpatient rehabilitation program augmented with RAGT may have played a role in substantial functional improvement. In SCI, successful recovery of locomotion relies on the ability of the spinal locomotor circuitry to utilize specific multisensory information to generate a locomotor pattern. 20 Task-specific locomotor training enhances the afferent feedback of the spinal locomotor circuits. Incorporation of RAGT induces the activation of central pattern generators, provides task-specific stepping practice, and increases the intensity and total duration of training while maintaining a physiological gait pattern. 21 Prescription of RAGT may be at the discretion of the rehabilitation team based on considerations for suitability. These include careful screening and exclusion of unsuitable cases with conditions such as severe joint contractures, pressure injuries, and pain as well as intrinsic factors such as receptiveness to unfamiliar technology and perceived benefits.
Shorter duration of Lokomat® training (five times per week for 2 weeks) was a limitation in the present case. In previous studies, RAGT was usually provided for 4-6 weeks with a frequency of 3-5 times per week. 21 With a longer duration of Lokomat® training, better ambulatory outcomes such as improvement from a walking frame to a walking stick or a longer distance of ambulation could have been achieved.
In conclusion, complete SCI secondary to postoperative seroma is a rare complication of corrective surgery for idiopathic scoliosis. Age, neurological level of injury, waiting time for decompressive surgery, and early intensive rehabilitation may play a role in improving ambulatory outcomes. A multidisciplinary rehabilitation program including RAGT to provide repetitive, task-specific locomotor training in eligible patients is deemed beneficial.

Disclaimer statements
Contributors None. Funding None.

Conflict of interest Authors have no conflict of interests.
Consent Consent was obtained from the patient and her guardian for this case report publication.