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
Akil P. Patel, Michael T. Koltz, Charles A. Sansur, Mangla Gulati and D. Kojo Hamilton
Patients requiring neurosurgical intervention are known to be at increased risk for deep vein thrombosis (DVT) and attendant morbidity and mortality. Pulmonary embolism (PE) is the most catastrophic sequela of DVT and is the direct cause of death in 16% of all in-hospital mortalities. Protocols for DVT screening and early detection, as well as treatment paradigms to prevent PE in the acute postoperative period, are needed in neurosurgery. The authors analyzed the effectiveness of weekly lower-extremity venous duplex ultrasonography (LEVDU) in patients requiring surgical intervention for cranial or spinal pathology for detection of DVT and prevention of PE.
Data obtained in 1277 consecutive patients admitted to a major tertiary care center requiring neurosurgical intervention were retrospectively reviewed. All patients underwent admission (within 1 week of neurosurgical intervention) LEVDU as well as weekly LEVDU surveillance if the initial study was normal. Additional LEVDU was ordered in any patient in whom DVT was suspected on daily clinical physical examination or in patients in whom chest CT angiography confirmed a pulmonary embolus. An electronic database was created and statistical analyses performed.
The overall incidence of acute DVT was 2.8% (36 patients). Of these cases of DVT, a statistically significant greater number (86%) were discovered on admission (within 1–7 days after admission) screening LEVDU (p < 0.05), whereas fewer were documented 8–14 days after admission (2.8%) or after 14 days (11.2%) postadmission. Additionally, for acute DVT detection in the present population, there were no underlying statistically significant risk factors regarding baseline physical examination, age, ambulatory status, or type of surgery.
The overall incidence of acute symptomatic PE was 0.3% and the mortality rate was 0%.
Performed within 1 week of admission in patients who will undergo neurosurgical intervention, LEVDU is effective in screening for acute DVT and initiating treatment to prevent PE, thereby decreasing the overall mortality rate. Routine LEVDU beyond this time point may not be needed to detect DVT and prevent PE unless a change in the patient's physical examination status is detected.
Michael T. Koltz, Cigdem Tosun, David B. Kurland, Turhan Coksaygan, Rudolph J. Castellani, Svetlana Ivanova, Volodymyr Gerzanich and J. Marc Simard
Encephalopathy of prematurity (EP) is common in preterm, low birth weight infants who require postnatal mechanical ventilation. The worst types of EP are the hemorrhagic forms, including choroid plexus, germinal matrix, periventricular, and intraventricular hemorrhages. Survivors exhibit life-long cognitive, behavioral, and motor abnormalities. Available preclinical models do not fully recapitulate the salient features of hemorrhagic EP encountered in humans. In this study, the authors evaluated a novel model using rats that featured tandem insults of transient prenatal intrauterine ischemia (IUI) plus transient postnatal raised intrathoracic pressure (RIP).
Timed-pregnant Wistar rats were anesthetized and underwent laparotomy on embryonic Day 19. Intrauterine ischemia was induced by clamping the uterine and ovarian vasculature for 20 minutes. Natural birth occurred on embryonic Day 22. Six hours after birth, the pups were subjected to an episode of RIP, induced by injecting glycerol (50%, 13 μl/g intraperitoneally). Control groups included naive, sham surgery, and IUI alone. Pathological, histological, and behavioral analyses were performed on pups up to postnatal Day 52.
Compared with controls, pups subjected to IUI+RIP exhibited significant increases in postnatal mortality and hemorrhages in the choroid plexus, germinal matrix, and periventricular tissues as well as intraventricularly. On postnatal Days 35–52, they exhibited significant abnormalities involving complex vestibulomotor function and rapid spatial learning. On postnatal Day 52, the brain and body mass were significantly reduced.
Tandem insults of IUI plus postnatal RIP recapitulate many features of the hemorrhagic forms of EP found in humans, suggesting that these insults in combination may play important roles in pathogenesis.
Michael T. Koltz, Adam J. Polifka, Andreas Saltos, Robert G. Slawson, Young Kwok, E. Francois Aldrich and J. Marc Simard
The object of this study was to assess outcomes in patients with arteriovenous malformations (AVMs) treated by Gamma Knife stereotactic radiosurgery (SRS); lesions were stratified by size, symptomatology, and Spetzler-Martin (S-M) grade.
The authors performed a retrospective analysis of 102 patients treated for an AVM with single-dose or staged-dose SRS between 1993 and 2004. Lesions were grouped by S-M grade, as hemorrhagic or nonhemorrhagic, and as small (< 3 cm) or large (≥ 3 cm). Outcomes included death, morbidity (new neurological deficit, new-onset seizure, or hemorrhage/rehemorrhage), nidus obliteration, and Karnofsky Performance Scale score.
The mean follow-up was 8.5 years (range 5–16 years). Overall nidus obliteration (achieved in 75% of patients) and morbidity (19%) correlated with lesion size and S-M grade. For S-M Grade I–III AVMs, nonhemorrhagic and hemorrhagic combined, treatment yielded obliteration rates of 100%, 89%, and 86%, respectively; high functional status (Karnofsky Performance Scale Score ≥ 80); and 1% mortality. For S-M Grade IV and V AVMs, outcomes were less favorable, with obliteration rates of 54% and 0%, respectively. The AVMs that were not obliterated had a mean reduction in nidus volume of 69% (range 35%–96%). On long-term follow-up, 10% of patients experienced hemorrhage/rehemorrhage (6% mortality rate), which correlated with lesion size and S-M grade; the mean interval to hemorrhage was 81 months.
For patients with S-M Grade I–III AVMs, SRS offers outcomes that are favorable and that, except for the timing of obliteration, appear to be comparable to surgical outcomes reported for the same S-M grades. Staged-dose SRS results in lesion obliteration in half of patients with S-M Grade IV lesions.