Paul Marcotte

Analysis of harvest morbidity and radiographic outcome using autograft for anterior cervical fusion

Study Design. Retrospective study of 184 autologous iliac crest bone grafts used for anterior cervical fusion in 144 procedures. Objectives. To evaluate the effect of autologous iliac crest bone graft harvest site on operation and recovery and to identify patients at risk for harvest morbidity. Summary of Background Data. Although autologous iliac crest bone graft is considered the most successful grafting material, concerns about harvest morbidity provide a rationale for considering allograft. Data about the use of autograft therefore would assist spinal surgeons in selecting the appropriate substrates for fusion after anterior cervical decompression. Methods. Statistical analysis based on patient gender, smoking history, obesity, and medical or pharmacologic risk factors for wound healing was used to evaluate morbidity after patient interviews and examinations. Limited assessment of radiographic outcome also was performed. Results. A second operation because of donor site morbidity was performed in four patients (2.8%), but only one (0.7%) with meralgia paresthetica had permanent sequelae. Superficial wound infection or dehiscence occurred in 5.6% of patients, with a disproportionate number of women, obese patients, and those with medical risk represented. Protracted wound symptoms of pain and poor cosmesis were reported in 2.8% and 3.5% of patients, respectively, and also were found in a significant number of female and obese patients. Evidence of fusion was present in 97% of cases. Conclusion. Autologous iliac crest bone graft harvest results in minimal major morbidity when regional anatomy is respected and careful technique is observed. The identification of patients at risk for minor complications suggests that allograft may be appropriate in these patients; however, prospective comparison is required to identify whether graft material or technical factors determine fusion success and relative benefit.

Assessment of spinal fusion. Critical evaluation of imaging techniques.

Before any radiologic imaging modality is employed in an investigation study, its efficacy must be critically assessed. The purpose of this report is to demonstrate how the choice of computed tomography imaging parameters affects the information provided by a computed tomographic examination. It is apparent from these results that imaging parameters must be optimized before the results of an imaging technique can be compared to other modes of diagnostic evaluation, including surgical observations.

Bleeding risk with ketorolac after lumbar microdiscectomy.

There is a need to improve postoperative analgesia to support the trend to shorter hospitalization after minimally invasive spine surgeries. Ketorolac Tromethamine has proven efficacy in decreasing postoperative pain but there is concern with postoperative epidural bleeding after spine procedures. We prospectively assessed the incidence of bleeding complications after microdiscectomy in patients treated with a single 30 mg intraoperative dose of Ketorolac subsequent to wound closure. Group 1 consisted of 44 patients, 24 women and 20 men with mean age of 35.7 years (20 to 68 y) treated with Ketorolac. Group 2 consisted of 45 patients, 28 men and 17 women with mean age 46.8 years (32 to 74 y), who underwent discectomy without Ketorolac. Postoperative bleeding complications were monitored along with pain levels and time to discharge. We detected no significant postoperative changes in coagulation parameters or bleeding from the surgical site in either group. Both group 1 and 2 had averaged preoperative visual analog scale scores for leg pain of 8. Group 1 had an average postoperative visual analog scale score of 2.6 compared with 4 for group 2 two hours after surgery. Single dose intravenous Ketorolac provided beneficial analgesia without significant increase in risk of bleeding after microdiscectomy, enabling us to consistently perform microdiscectomy as an ambulatory procedure. Meticulous hemostasis should be accomplished before closure. Prolonged postoperative use is a promising alternative to narcotics.

Spinal cord arteriovenous fistulas involving the conus medullaris: presentation, management, and embryologic considerations

BACKGROUND Spinal cord arteriovenous fistulas (SCAVF) are uncommon congenital lesions that usually involve the most caudal aspects of the cord. We present three cases of SCAVF that illustrate the clinical manifestations and possible management options. The characteristic involvement of the conus medullaris and an associated tethered spinal cord in one of our patient suggests that a disorder of secondary neurulation may be involved in the formation of these arteriovenous shunt lesions. METHODS Review of records and radiologic studies in three consecutive patients with SCAVFs treated at this institution. RESULTS All three patients had SCAVF involving the lower lumbar spinal cord segments or the conus. One of the conus lesions was associated with tethering of the spinal cord. One small lesion (Type A) was treated surgically, whereas the two larger lesions (Type B) were treated using interventional neuroradiologic techniques. CONCLUSIONS Both surgical and endovascular method have a role in management of these unusual spinal cord vascular malformations. The association with tethered cord suggests that the propensity for SCAVM to occur in the most caudal portions of the spinal cord may result from failure of secondary neurulation to properly develop the unique and complex vascular anatomy of the region.

Cost-effectiveness of confirmatory techniques for the placement of lumbar pedicle screws

OBJECT There is considerable variation in the use of adjunctive technologies to confirm pedicle screw placement. Although there is literature to support the use of both neurophysiological monitoring and isocentric fluoroscopy to confirm pedicle screw positioning, there are no studies examining the cost-effectiveness of these technologies. This study compares the cost-effectiveness and efficacy of isocentric O-arm fluoroscopy, neurophysiological monitoring, and postoperative CT scanning after multilevel instrumented fusion for degenerative lumbar disease. METHODS Retrospective data were collected from 4 spine surgeons who used 3 different strategies for monitoring of pedicle screw placement in multilevel lumbar degenerative disease. A decision analysis model was developed to analyze costs and outcomes of the 3 different monitoring strategies. A total of 448 surgeries performed between 2005 and 2010 were included, with 4 cases requiring repeat operation for malpositioned screws. A sample of 64 of these patients was chosen for structured interviews in which the EuroQol-5D questionnaire was used. Expected costs and quality-adjusted life years were calculated based on the incidence of repeat operation and its negative effect on quality of life and costs. RESULTS The decision analysis model demonstrated that the O-arm monitoring strategy is significantly (p < 0.001) less costly than the strategy of postoperative CT scanning following intraoperative uniplanar fluoroscopy, which in turn is significantly (p < 0.001) less costly than neurophysiological monitoring. The differences in effectiveness of the different monitoring strategies are not significant (p = 0.92). CONCLUSIONS Use of the O-arm for confirming pedicle screw placement is the least costly and therefore most cost-effective strategy of the 3 techniques analyzed.

Papilledema as a manifestation of a spinal subdural abscess.

Papilledema is an uncommon presentation of spinal cord processes. Spinal subdural abscess (SSA) is a rare site of post-operative infection. We report a patient who developed papilledema as the primary manifestation of a post-operative lumbar subdural abscess. A spinal abscess should be considered in the post-operative spinal surgery patient who develops papilledema in the setting of persistent back pain. The increased intracranial pressure associated with lumbar spinal cord abscess most likely results from a markedly elevated cerebrospinal fluid (CSF) protein or the disruption of CSF flow in the spinal cul-de-sac.

Civilian gunshot wounds to the atlantoaxial spine: A report of 10 cases treated using a multidisciplinary approach

OBJECT Gunshot wounds to the atlantoaxial spine are uncommon injuries and rarely require treatment, as a bullet traversing this segment often results in a fatal injury. Additionally, these injuries are typically biomechanically stable. The authors report a series of 10 patients with gunshot wounds involving the lateral mass and/or bodies of the atlantoaxial complex. Their care is discussed and conclusions are drawn from these cases to identify the optimal treatment for these injuries. METHODS A retrospective review was conducted of patients presenting to the emergency rooms of 3 institutions with gunshot wounds involving the atlantoaxial spine. Mechanism of injury and neurological status were obtained, as was the extent of the osteoligamentous, vascular, and neurological injuries. Nonoperative and operative treatment, complications, and clinical and radiographic outcome were recorded. The data were then analyzed to determine the neurological and biomechanical prognosis of these injuries, the utility of the various diagnostic modalities in the acute management of the injuries, and the nature and effectiveness of the nonoperative and operative treatment modalities. RESULTS Ten patients with gunshot wounds involving the lateral mass and/or bodies of the atlantoaxial complex were identified. All but 2 patients sustained a vertebral artery injury. Each patient was evaluated using cervical radiographs, CT scans, and vascular imaging, 8 in the form of digital subtraction angiography and 2 with high-resolution CT angiography. Uncomplicated patients were treated conservatively using cervical collar immobilization, local wound care, and antibiotics. One patient was treated using a halo for instability and 1 underwent posterior fusion following a posterolateral decompression for delayed myelopathy. One patient underwent transoral resection of a bullet fragment. One patient underwent embolization for a symptomatic arteriovenous fistula and a second patient underwent a neck exploration and a jugular vein ligation. None of the patients received anticoagulation therapy. The mean follow-up duration was 13 months. All but 2 patients regained their previous functional status and all ultimately attained a mechanically stable spine. CONCLUSIONS These 10 patients represent a rare form of cervical spine penetrating injury. Unilateral gunshot wounds to the atlantoaxial complex are usually stable and the need for acute surgical intervention is rare. Unilateral vertebral artery injury is well tolerated and any information provided by angiography does not alter the acute management of the patient. Vascular complications from gunshot wounds can be managed effectively by endovascular techniques.

A patient with thoracic intradural disc herniation

Intradural disc herniation is a rare disease that occurs most commonly in the lumbar region, while fewer than 5% occur in the thoracic and cervical regions. We report a patient with thoracic intradural disc herniation at T12-L1 who presented with radiculopathy and motor weakness. The preoperative MRI did not demonstrate an intradural lesion, and it was identified intraoperatively by inspection and palpation of the thecal sac. The disc was removed, and the patient experienced good neurological recovery and remains pain free 1 year after surgery.

Degenerative Disease of the Cervical Spine

This chapter will focus on cervical spondylosis and the resulting symptomatology, including pain, nerve root and spinal cord compression. The pathophysiology, imaging diagnostics and treatments for cervical spine degeneration are discussed. A variety of operative and non-operative treatment modalities are available, including rest, anti-inflammatories, decompressive surgery and fusion surgery, with the goal of treatment being to diminish pain, restore neurological function and re-establish spinal stability.

Spinal dural arteriovenous malformations. Intraoperative evoked potential evidence for pathophysiology. A case report.

Study Design This case report details intraoperative evoked potential changes during surgical removal of a T8 dural arteriovenous malformation. Objectives The pattern of changes in somatosensory‐evoked responses during surgical correction of a spinal dural arteriovenous malformation can illuminate the pathophysiologic process behind the clinical symptoms. Summary of Background Data Arteriovenous malformation of the spinal dura can manifest with multiple symptoms, including progressive myelopathy and pain. The pathophysiologic process behind these symptoms could be either direct compression of the spinal cord by the arteriovenous malformation, ischemia resulting from shunting of the blood flow away from the cord, or increased venous pressure. Methods To investigate these hypotheses further, the results of posterior tibial evoked potentials obtained during surgical removal of a T8 dural arteriovenous malformation were analyzed. Results At baseline, the cortical (P40) potential was markedly prolonged bilaterally. During surgery, just after the dura was opened, a marked increase was observed in the latencies of the P40 and P60 components of the evoked response on the right, which began to resolve as soon as the arteriovenous malformation was occluded. Only minimal changes were seen on the left. Conclusions These results are most consistent with the increased venous pressure hypothesis for the pathogenesis of neurologic symptoms in dural arteriovenous malformations.