Traumatic central cord syndrome (TCCS), regardless of its biomechanics, is the most frequently encountered incomplete spinal cord injury. Patients with TCCS present with disproportionate weakness of the upper extremities, and variable sensory loss and bladder dysfunction. Fractures and/or subluxations, forced hyperextension, and herniated nucleus pulposus are the main pathogenetic mechanisms of TCCS. Nearly 50% of patients with TCCS suffer from congenital or degenerative spinal stenosis and sustained their injuries during hyperextension as originally described by Schneider in 1954. Immunohistochemical and imaging studies indicate mild to moderate insult to axons and their ensheathing myelin in the lateral funiculi culminating in cytoskeletal injury and impaired conduction. More than one-half of these patients enjoy spontaneous recovery of motor weakness; however, as time goes on, lack of manual dexterity, neuropathic pain, spasticity, bladder dysfunction, and imbalance of gait render their activities of daily living nearly impossible. Based on the current level of evidence, there is no clear indication of the timing of decompression for relief of sustained spinal cord compression in hyperextension injuries. Future research, taking advantage of validated digital imaging data such as maximum canal compromise, maximum spinal cord compression, and lesion length on the CT and MR images, as well as more sensitive measures of bladder and hand function, spasticity, and neuropathic pain may help tailor surgery for a specific group of these patients.
Bizhan Aarabi, Michael Koltz and David Ibrahimi
Narlin Beaty, Justin Slavin, Cara Diaz, Kyle Zeleznick, David Ibrahimi and Charles A. Sansur
Gunshot wounds (GSWs) to the cervical spine have been examined in a limited number of case series, and operative management of this traumatic disease has been sparsely discussed. The current literature supports and the authors hypothesize that patients without neurological deficit need neither surgical fusion nor decompression. Patients with GSWs and neurological deficits, however, pose a greater management challenge. The authors have compiled the experience of the R Adams Cowley Shock Trauma Center in Baltimore, Maryland, over the past 12 years, creating the largest series of such injuries, with a total number of 40 civilian patients needing neurosurgical evaluation. The current analysis examines presenting bone injury, surgical indication, presenting neurological examination, and neurological outcome. In this study, the authors characterize the incidence, severity, and recovery potential of cervical GSWs. The rate of unstable fractures requiring surgical intervention is documented. A detailed discussion of surgical indications with a treatment algorithm for cervical instability is offered.
A total of 144 cervical GSWs were retrospectively reviewed. Of these injuries, 40 had documented neurological deficits. No neurosurgical consultation was requested for patients without deficit. Epidemiological and clinical information was collected on patients with neurological deficit, including age, sex, timing, indication, type of surgery, initial examination after resuscitation, follow-up examination, and imaging data.
Twenty-eight patients (70%) presented with complete neurological deficits and 12 patients (30%) presented with incomplete injuries. Fourteen (35%) of the 40 patients underwent neurosurgical intervention. Twelve patients (30%) required intervention for cervical instability. Seven patients required internal fixation involving 4 anterior fusions, 2 posterior fusions, and 1 combined approach. Five patients were managed with halo immobilization. Two patients underwent decompression alone for neurological deterioration and persistent compressive injury, both of whom experienced marked neurological recovery. Follow-up was obtained in 92% of cases. Three patients undergoing stabilization converted at least 1 American Spinal Injury Association (ASIA) Impairment Scale (AIS) grade and the remaining operative cases experienced small ASIA motor score improvement. Eighteen patients underwent inpatient MRI. No patient suffered complications or neurological deterioration related to retained metal. Three of 28 patients presenting with AIS Grade A improved to Grade B. For those 12 patients with incomplete injury, 1 improved from AIS Grade C to D, and 3 improved from Grade D to E.
Spinal cord injury from GSWs often results in severe neurological deficits. In this series, 30% of these patients with deficits required intervention for instability. This is the first series that thoroughly documents AIS improvement in this patient population. Adherence to the proposed treatment algorithm may optimize neurological outcome and spine stability.
Charles A. Sansur, Nicholas M. Caffes, David M. Ibrahimi, Nathan L. Pratt, Evan M. Lewis, Ashley A. Murgatroyd and Bryan W. Cunningham
Optimal strategies for fixation in the osteoporotic lumbar spine remain a clinical issue. Classic transpedicular fixation in the osteoporotic spine is frequently plagued with construct instability, often due to inadequate cortical screw–bone purchase. A cortical bone trajectory maximizes bony purchase and has been reported to provide increased screw pullout strength. The aim of the current investigation was to evaluate the biomechanical efficacy of cortical spinal fixation as a surgical alternative to transpedicular fixation in the osteoporotic lumbar spine under physiological loading.
Eight fresh-frozen human spinopelvic specimens with low mean bone mineral densities (T score less than or equal to –2.5) underwent initial destabilization, consisting of laminectomy and bilateral facetectomies (L2–3 and L4–5), followed by pedicle or cortical reconstructions randomized between levels. The surgical constructs then underwent fatigue testing followed by tensile load to failure pullout testing to quantify screw pullout force.
When stratifying the pullout data with fixation technique and operative vertebral level, cortical screw fixation exhibited a marked increase in mean load at failure in the lower vertebral segments (p = 0.188, 625.6 ± 233.4 N vs 450.7 ± 204.3 N at L-4 and p = 0.219, 640.9 ± 207.4 N vs 519.3 ± 132.1 N at L-5) while transpedicular screw fixation demonstrated higher failure loads in the superior vertebral elements (p = 0.024, 783.0 ± 516.1 N vs 338.4 ± 168.2 N at L-2 and p = 0.220, 723.0 ± 492.9 N vs 469.8 ± 252.0 N at L-3). Although smaller in diameter and length, cortical fixation resulted in failures that were not significantly different from larger pedicle screws (p > 0.05, 449.4 ± 265.3 N and 541.2 ± 135.1 N vs 616.0 ± 384.5 N and 484.0 ± 137.1 N, respectively).
Cortical screw fixation exhibits a marked increase in mean load at failure in the lower vertebral segments and may offer a viable alternative to traditional pedicle screw fixation, particularly for stabilization of lower lumbar vertebral elements with definitive osteoporosis.
Randall Schultz Jr., Andrew Steven, Aaron Wessell, Nancy Fischbein, Charles A. Sansur, Dheeraj Gandhi, David Ibrahimi and Prashant Raghavan
Dorsal arachnoid webs (DAWs) and spinal cord herniation (SCH) are uncommon abnormalities affecting the thoracic spinal cord that can result in syringomyelia and significant neurological morbidity if left untreated. Differentiating these 2 entities on the basis of clinical presentation and radiological findings remains challenging but is of vital importance in planning a surgical approach. The authors examined the differences between DAWs and idiopathic SCH on MRI and CT myelography to improve diagnostic confidence prior to surgery.
Review of the picture archiving and communication system (PACS) database between 2005 and 2015 identified 6 patients with DAW and 5 with SCH. Clinical data including demographic information, presenting symptoms and neurological signs, and surgical reports were collected from the electronic medical records. Ten of the 11 patients underwent MRI. CT myelography was performed in 3 patients with DAW and in 1 patient with SCH. Imaging studies were analyzed by 2 board-certified neuroradiologists for the following features: 1) location of the deformity; 2) presence or absence of cord signal abnormality or syringomyelia; 3) visible arachnoid web; 4) presence of a dural defect; 5) nature of dorsal cord indentation (abrupt “scalpel sign” vs “C”-shaped); 6) focal ventral cord kink; 7) presence of the nuclear trail sign (endplate irregularity, sclerosis, and/or disc-space calcification that could suggest a migratory path of a herniated disc); and 8) visualization of a complete plane of CSF ventral to the deformity.
The scalpel sign was positive in all patients with DAW. The dorsal indentation was C-shaped in 5 of 6 patients with SCH. The ventral subarachnoid space was preserved in all patients with DAW and interrupted in cases of SCH. In no patient was a web or a dural defect identified.
DAW and SCH can be reliably distinguished on imaging by scrutinizing the nature of the dorsal indentation and the integrity of the ventral subarachnoid space at the level of the cord deformity.
Justin S. Smith, Manish Singh, Eric Klineberg, Christopher I. Shaffrey, Virginie Lafage, Frank J. Schwab, Themistocles Protopsaltis, David Ibrahimi, Justin K. Scheer, Gregory Mundis Jr., Munish C. Gupta, Richard Hostin, Vedat Deviren, Khaled Kebaish, Robert Hart, Douglas C. Burton, Shay Bess and Christopher P. Ames
Increased sagittal vertical axis (SVA) correlates strongly with pain and disability for adults with spinal deformity. A subset of patients with sagittal spinopelvic malalignment (SSM) have flatback deformity (pelvic incidence–lumbar lordosis [PI-LL] mismatch > 10°) but remain sagittally compensated with normal SVA. Few data exist for SSM patients with flatback deformity and normal SVA. The authors' objective was to compare baseline disability and treatment outcomes for patients with compensated (SVA < 5 cm and PI-LL mismatch > 10°) and decompensated (SVA > 5 cm) SSM.
The study was a multicenter, prospective analysis of adults with spinal deformity who consecutively underwent surgical treatment for SSM. Inclusion criteria included age older than 18 years, presence of adult spinal deformity with SSM, plan for surgical treatment, and minimum 1-year follow-up data. Patients with SSM were divided into 2 groups: those with compensated SSM (SVA < 5 cm and PI-LL mismatch > 10°) and those with decompensated SSM (SVA ≥ 5 cm). Baseline and 1-year follow-up radiographic and health-related quality of life (HRQOL) outcomes included Oswestry Disability Index, Short Form–36 scores, and Scoliosis Research Society–22 scores. Percentages of patients achieving minimal clinically important difference (MCID) were also assessed.
A total of 125 patients (27 compensated and 98 decompensated) met inclusion criteria. Compared with patients in the compensated group, patients in the decompensated group were older (62.9 vs 55.1 years; p = 0.004) and had less scoliosis (43° vs 54°; p = 0.002), greater SVA (12.0 cm vs 1.7 cm; p < 0.001), greater PI-LL mismatch (26° vs 20°; p = 0.013), and poorer HRQOL scores (Oswestry Disability Index, Short Form-36 physical component score, Scoliosis Research Society-22 total; p ≤ 0.016). Although these baseline HRQOL differences between the groups reached statistical significance, only the mean difference in Short Form–36 physical component score reached threshold for MCID. Compared with baseline assessment, at 1 year after surgery improvement was noted for patients in both groups for mean SVA (compensated –1.1 cm, decompensated +4.8 cm; p ≤ 0.009), mean PI-LL mismatch (compensated 6°, decompensated 5°; p < 0.001), and all HRQOL measures assessed (p ≤ 0.005). No significant differences were found between the compensated and decompensated groups in the magnitude of HRQOL score improvement or in the percentages of patients achieving MCID for each of the outcome measures assessed.
Decompensated SSM patients with elevated SVA experience significant disability; however, the amount of disability in compensated SSM patients with flatback deformity caused by PI-LL mismatch but normal SVA is underappreciated. Surgical correction of SSM demonstrated similar radiographic and HRQOL score improvements for patients in both groups. Evaluation of SSM should extend beyond measuring SVA. Among patients with concordant pain and disability, PI-LL mismatch must be evaluated for SSM patients and can be considered a primary indication for surgery.