John K. Houten

Paraplegia after lumbosacral nerve root block: report of three cases.

BACKGROUND CONTEXT Lumbar nerve root blocks and epidural steroid injections are frequently employed in the management of degenerative conditions of the lumbar spine, but relatively few papers have been published that address the complications associated with these interventions. Serious complications include epidural abscess, arachnoiditis, epidural hematoma, cerebrospinal fluid fistula and hypersensitivity reaction to injectate. Although transient paraparesis has been described after inadvertent intrathecal injection, an immediate and lasting deficit has not been previously described as sequelae of a nerve root block. PURPOSE We present three cases in which either persisting paraplegia or paraparesis occurred immediately after administration of a lumbar nerve root block and propose a mechanism for this devastating but previously unreported complication. STUDY DESIGN/SETTING Case reports of three patients. PATIENT SAMPLE Three patients, two women and one man ranging in age from 42 to 64 years, underwent three procedures performed at three different facilities, in the hands of two different injectionists. In each instance, penetration of the dura was not thought to have occurred. In two procedures the needles were placed transforamenally, one at L3-4 on the left and one at L3-4 on the right, and in the third the needle tip was placed immediately lateral to the S1 nerve root. OUTCOME MEASURES Patient follow-up data from medical office records. METHODS In each case, needle placement was verified with injection of a contrast media in conjunction with either computerized tomography or biplanar fluoroscopy. No backbleeding or cerebrospinal fluid was encountered upon aspiration in any of the procedures. Magnetic resonance imaging (MRI) was performed within 48 hours of injury in all patients. RESULTS In each patient, paraplegia suddenly ensued after instillation of the steroid solution and, in each instance, postprocedure MRI revealed increased signal in the low thoracic spinal cord on T2-weighted imaging consistent with edema. The sudden onset of neurological deficit and the imaging changes noted in the spinal cord point to a vascular explanation for these injuries. We postulate that in these patients the spinal needle either penetrated or caused injury to an abnormally low dominant radiculomedullary artery, a recognized anatomical variant. This vessel, also known as the artery of Adamkiewicz, in 85% of individuals arises between T9 and L2, usually from the left, but in a minority of people may arise from the lower lumbar spine and rarely even from as low as S1. The artery of Adamkiewicz travels with the nerve root through the neural foramen and irrigates the anterior spinal artery. Injury of it or injection of particulate matter into it, as what may happen with the commonly used epidural steroid injectates, may result in infarction of the lower thoracic spinal cord, producing the clinical and imaging findings seen in these three patients. CONCLUSIONS We present the cases of three patients who had lasting paraplegia or paraparesis after the performance of a nerve root block. We propose that the mechanism for this rare but devastating complication is the concurrence of two uncommon circumstances, the presence of an unusually low origin of the artery of Adamkiewicz and an undetected intraarterial penetration of the procedure needle.

Laminectomy and posterior cervical plating for multilevel cervical spondylotic myelopathy and ossification of the posterior longitudinal ligament: effects on cervical alignment, spinal cord compression, and neurological outcome.

OBJECTIVE Multilevel anterior decompressive procedures for cervical spondylotic myelopathy or ossification of the posterior longitudinal ligament may be associated with a high incidence of neurological morbidity, construct failure, and pseudoarthrosis. We theorized that laminectomy and stabilization of the cervical spine with lateral mass plates would obviate the disadvantages of anterior decompression, prevent the development of kyphotic deformity frequently seen after uninstrumented laminectomy, decompress the spinal cord, and produce neurological results equal or superior to those achieved by multilevel anterior procedures. METHODS We retrospectively reviewed the records of 38 patients who underwent laminectomy and lateral mass plating for cervical spondylotic myelopathy or ossification of the posterior longitudinal ligament between January 1994 and November 2001. Seventy-six percent of patients had spondylosis, 18% had ossification of the posterior longitudinal ligament, and 5% had both. Clinical presentation included upper extremity sensory complaints (89%), gait difficulty (70%), and hand use deterioration (67%). Spasticity was present in 83%, and weakness of one or more muscle groups was seen in 79%. Spinal cord signal abnormality on sagittal T2-weighted magnetic resonance imaging (MRI) was seen in 68%. Neurological evaluation was performed using a modification of the Japanese Orthopedic Association Scale for functional assessment of myelopathy, the Cooper Scale for separate evaluation of upper and lower extremity motor function, and a five-point scale for evaluation of strength in individual muscle groups. Lateral cervical spine x-rays were analyzed using a curvature index to determine maintenance of alignment. Each surgically decompressed level was graded on a four-point scale using axial MRI to assess the adequacy of decompression. Late follow-up was conducted by telephone interview. RESULTS Laminectomy was performed at a mean 4.6 levels. Follow-up was obtained at a mean of 30.2 months after the procedure. The score on the modified Japanese Orthopedic Association scale improved in 97% of patients from a mean of 12.9 preoperatively to 15.58 postoperatively (P < 0.0001). In the upper extremities, function measured by the Cooper Scale improved from 1.8 to 0.7 (P < 0.0001), and in the lower extremities, function improved from 1.0 to 0.4 (P < 0.0002). There was a statistically significant improvement in strength in the triceps (P < 0.0001), iliopsoas (P < 0.0002), and hand intrinsic muscles (P < 0.0001). X-rays obtained at a mean of 5.9 months after surgery revealed no change in spinal alignment as measured by the curvature index. There was a decrease in the mean preoperative compression grade from 2.46 preoperatively to 0.16 postoperatively (P < 0.0001). There was no correlation between neurological outcome and the presence of spinal cord signal change on T2-weighted MRI scans, patient age, duration of symptoms, or preoperative medical comorbidity. CONCLUSION Multilevel laminectomy and instrumentation with lateral mass plates is associated with minimal morbidity, provides excellent decompression of the spinal cord (as visualized on MRI), produces immediate stability of the cervical spine, prevents kyphotic deformity, and precludes further development of spondylosis at fused levels. Neurological outcome is equal or superior to multilevel anterior procedures and prevents spinal deformity associated with laminoplasty or noninstrumented laminectomy.

Pediatric Intramedullary Spinal Cord Tumors: Special Considerations

Intramedullary spinal cord tumors (IMSCTs) of the pediatric population are rare and comprise thirty-five percent of intraspinal neoplasms. Low-grade astrocytomas predominate; ependymomas increase in frequency with ascending age and become the most frequent IMSCT in adults. Gangliogliomas are very rare in adults but comprise nearly thirty percent of tumors in children under three years of age. The cervical spine is the region of the spine most affected. Pain is the most common presenting symptom with weakness, gait deterioration, torticollis also frequently reported. Hydrocephalus occurs with greater frequency than in adult patients and often requires a shunt. Motor and sensory evoked potential monitoring is routinely utilized. Osteoplastic laminotomy is performed to forestall the development of progressive spinal deformity. Gross total resection is feasible in most ependymomas and results in surgical cure. Astrocytomas are infiltrating neoplasms and gross total resection is occasionally possible only in the pediatric population. However, the role of radical resection of low-grade fibrillary astrocytomas of the spinal cord in children has not been definitively demonstrated in the literature. Outcome for low-grade astrocytomas is better in children than adults, but not as favorable as that for ependymomas. Malignant tumors have dismal outcomes and surgery in these patients serves only to provide a diagnosis.

Nerve injury during the transpsoas approach for lumbar fusion

A lateral transpsoas approach to achieve interbody fusion in the lumbar spine using either the extreme lateral interbody fusion or direct lateral interbody fusion technique is an increasingly popular method to treat spinal disease. Dissection and dilation through the iliopsoas muscle places the lumbosacral plexus at risk for injury, but there is very limited information in the published literature about adverse clinical events resulting in postoperative motor deficits or reports of failure of electrophysiological monitoring to detect nerve injury. The authors present 2 cases of postoperative motor deficits following the transpsoas approach not detected by intraoperative monitoring, review the medical literature, and discuss strategies for complication avoidance.

Clinical Assessment of Percutaneous Lumbar Pedicle Screw Placement Using the O-Arm Multidimensional Surgical Imaging System

BACKGROUND: Increasing popularity of minimally invasive surgery for lumbar fusion has led to dependence upon intraoperative fluoroscopy for pedicle screw placement, because limited muscle dissection does not expose the bony anatomy necessary for traditional, freehand techniques nor for registration steps in image-guidance techniques. This has raised concerns about cumulative radiation exposure for both surgeon and operating room staff. The recent introduction of the O-arm Multidimensional Surgical Imaging System allows for percutaneous placement of pedicle screws, but there is limited clinical experience with the technique and data examining its accuracy. OBJECTIVE: We present the first large clinical series of percutaneous screw placement using navigation of O-arm imaging and compare the results with the fluoroscopy-guided method. METHODS: A retrospective review of a 24-month period identified patients undergoing minimally invasive lumbar interbody fusion. The O-arm was introduced in the middle of this period and was used for all subsequent patients. Accuracy of screw placement was assessed by examination of axial computed tomography or O-arm scans. RESULTS: The fluoroscopy group included 141 screws in 42 patients, and the O-arm group included 205 screws in 52 patients. The perforation rate was 12.8% in the fluoroscopy group and 3% in the O-arm group (P < .001). Single-level O-arm procedures took a mean 200 (153-241) minutes, whereas fluoroscopy took 221 (178-302) minutes (P < .03). CONCLUSION: Percutaneous pedicle screw placement with the O-arm Multidimensional Intraoperative Imaging System is a safe and effective technique and provided improved overall accuracy and reduced operative time compared with conventional fluoroscopic techniques.

Clinical Correlations of Cervical Myelopathy and the Hoffmann Sign

OBJECT The Hoffmann sign is commonly used in clinical practice to assess cervical spine disease. It is unknown whether the sign correlates with the severity of myelopathy, and no consensus exists regarding the significance of a positive sign in asymptomatic individuals. METHODS In a retrospective review of cervical spine surgeries for myelopathy due to cervical spondylosis, ossification of the posterior longitudinal ligament, or disc herniation performed at a tertiary center, the authors compiled data on the presence of hyperreflexia, the Hoffmann and Babinski signs, and modified Japanese Orthopaedic Association (mJOA) scale scores. Then, in a prospective evaluation, new patients with lumbar spine complaints were examined for the presence of a Hoffmann sign, and, if present, a cervical MR imaging study was assessed for cord compression. RESULTS Of the 225 surgically treated patients, a Hoffmann sign occurred in 68%, hyperreflexia in 60%, and a Babinski sign in 33%. In patients with milder disability (mJOA Scores 14-16), the Hoffmann sign was present in 46%, whereas a Babinski sign occurred in 10%; in those with severe myelopathy and mJOA scores of < or =10, the Hoffmann sign was present in 81% and the Babinski sign in 83%. Of 290 patients presenting exclusively with lumbar spine-related complaints, 36 (12%) had a positive Hoffmann sign. Magnetic resonance imaging demonstrated spinal cord compression in 91% when the sign was present bilaterally and 50% when positive unilaterally. CONCLUSIONS In patients surgically treated for cervical myelopathy, the Hoffmann sign is more prevalent and more likely to be seen in individuals with less severe neurological deficits than the Babinski sign. In patients with lumbar symptoms, a bilateral Hoffmann sign was a highly sensitive marker for occult cervical cord compression, whereas a unilateral Hoffmann sign correlated with similar disease in about one-half of patients.

The Unique Characteristics of “Upper” Lumbar Disc Herniations

OBJECTIVE:To compare the characteristics, presentation, and surgical outcome of patients with microdiscectomies at L1–L2 and L2–L3 with those we treated at L3–L4. We further sought to compare these results with those reported in the literature for discectomies at the L4–L5 and L5–S1 levels. METHODS:We reviewed the clinical data collected from 69 patients who had 72 L1–L2, L2–L3, and L3–L4 microdiscectomies performed from 1989 to 1999 at the New York University Medical Center. Patients who had surgery at L1–L2 or L2–L3 were grouped and compared with those treated at the L3–L4 level. Patients’ charts were retrospectively reviewed at a mean of 12.9 months after surgery for presenting signs and symptoms, patient characteristics, and surgical outcome. Long-term follow-up via telephone interview was obtained at an average of 81.3 months after surgery. RESULTS:In the L1–L2 + L2–L3 group, 58% of the patients had previous lumbar disc surgery, compared with only 10% of those in the L3–L4 group, and 20% in the L1–L2 + L2–L3 group required a fusion during the procedure compared with only 10% in the L3–L4 group. These differences are both statistically significant. The short-term chart review demonstrates that only 58% and 53% of patients in the L1–L2 + L2–L3 group were improved with regard to radicular and back pain, respectively, whereas those in the L3–L4 group reported 94 and 87% rates of improvement in the same categories, both highly statistically significant findings. The long-term follow-up confirmed a highly statistically significantly worse outcome in the L1–L2 + L2–L3 group, with only 33% of patients reporting an improvement in their economic or functional status, compared with an 88% rate of improvement in the L3–L4 group. The outcome of our patients with L3–L4 herniations was similar to that reported in the literature for herniations at L4–L5 and L5–S1. CONCLUSION:Herniated discs at the L1–L2 or L2–L3 level are different entities from those at lower levels of the lumbar spine. The surgical outcome in terms of postoperative back and radicular pain is worse for herniated discs at L1–L2 and L2–L3 compared with those treated at L3–L4. Our patients with L1–L2 or L2–L3 surgically treated herniated discs were more likely to have had previous lumbar surgery and required a fusion more often than their counterparts with L3–L4 herniated discs.

Thoracic paraganglioma presenting with spinal cord compression and metastases.

We report a case of a 41-year-old man with a primary thoracic spine paraganglioma presenting with spinal cord compression and distant metastasis. Paragangliomas arising within the spinal canal are rare and when they occur are usually found in the intradural, extramedullary compartment and in the lumbosacral region. Thoracic paragangliomas are very rare, with only five prior cases reported in the literature and with distant metastasis seen in only one of these. In this case, the tumor was entirely extradural and produced extensive sclerosis of the surrounding vertebrae. The clinical, radiographic, and pathologic features of this case are detailed and the relevant literature is reviewed.

Bowel injury as a complication of microdiscectomy: Case report and literature review

Intestinal injury is a rare complication of lumbar disc surgery, resulting from inadvertent penetration of the anterior annulus fibrosus and anterior longitudinal ligament. Patients typically complain of abdominal pain and distention developing over the course of several days. Imaging with plain upright chest radiographs or abdominal computed tomography may demonstrate free air in the abdominal cavity. We report a case of intestinal perforation after microscopic lumbar discectomy and present the diagnostic postoperative imaging. In addition, we review the relevant literature and discuss techniques that may be employed to avoid this complication.

Symptomatic progression of degenerative scoliosis after decompression and limited fusion surgery for lumbar spinal stenosis

Significant degenerative scoliosis together with lumbar spinal stenosis increases the complexity of planning a surgical intervention for iatrogenic instability may be introduced by decompression in the midst of the curve, especially at or near the curve apex, that may lead to more rapid progression of a deformity, especially if surgery is at, or is near, the apex of the curve and a listhesis is present. Surgical options include simple laminectomy, a laminectomy with limited fusion, or an extensive fusion that addresses the overall curve, but there is no consensus as to the best approach. There is scant information in the literature about specific instances of failure of a limited surgical approach from which any instructive lessons may be learned. We report a surgical failure in a 59-year-old woman with degenerative lumbar stenosis and scoliosis from L3-5 and L3-4 disc herniation treated with a simple hemilaminectomy and discectomy, a subsequent fusion for symptomatic progression of deformity, and a third surgery to fuse the entire scoliotic curve after development of severe deformity, pain, and neurological deficits. We conclude that surgical decision-making should take into consideration any risk factors for deformity progression as well as overall sagittal and coronal balance and advise that similar patients be followed for a lengthy period following surgery to monitor for stability.