Adrian Casey

Intermediate follow-up after treatment of degenerative disc disease with the Bryan Cervical Disc Prosthesis: Single-level and bi-level

Study Design. Prospective, concurrently enrolled, multicenter trials of the Bryan Cervical Disc Prosthesis (Medtronic Sofamor Danek, Memphis, TN) were conducted for the treatment of patients with single-level and two-level (bi-level) degenerative disc disease of the cervical spine. Objectives. The studies were designed to determine whether new functional intervertebral cervical disc prosthesis can provide relief from objective neurologic symptoms and signs, improve the patient’s ability to perform activities of daily living, decrease pain, and maintain stability and segmental motion. Summary of Background Data. The concept of accelerated degeneration of adjacent disc levels as a consequence of increased stress caused by interbody fusion of the cervical spine has been widely postulated. Therefore, reconstruction of a failed intervertebral disc with functional disc prosthesis should offer the same benefits as fusion while simultaneously providing motion and thereby protecting the adjacent level discs from the abnormal stresses associated with fusion. Methods. Patients with symptomatic cervical radiculopathy and/or myelopathy underwent implantation with the Bryan prosthesis after a standard anterior cervical discectomy. At scheduled follow-up periods, the effectiveness of the device was characterized by evaluating each patient’s pain, neurologic function, and radiographically measured range of motion at the implanted level. Results. Clinical success for both studies exceeded the study acceptance criteria of 85%. At 1-year follow-up, the flexion-extension range of motion per level averaged 7.9 ± 5.3 degrees in the single-level study and 7.4 ± 5.1 degrees in the bilevel study. No devices have been explanted. Conclusions. Discectomy and implantation of the device alleviates neurologic symptoms and signs similar to anterior cervical discectomy and fusion. Radiographic evidence supports maintenance of motion. The procedure is safe and the patients recover quickly. At least 5 years of follow-up will be needed to assess the long-term functionality of the prosthesis and protective influence on adjacent levels.

A novel technique for laminoplasty augmentation of spinal canal area using titanium miniplate stabilization. A computerized morphometric analysis.

Study Design Titanium miniplates are used to secure the posterior elements in the open position after expansive open‐door laminoplasty. Preoperative and postoperative spinal canal dimensions are measured to assess the effectiveness of this technique. Objectives To develop a simple yet effective technique to stabilize the posterior elements after laminoplasty, and to compare preoperative and postoperative spinal canal dimensions to accepted normal values. Summary of Background Data Expansive open‐door laminoplasty has been offered as a simple alternative to laminectomy, which has been associated with postoperative kyphosis. Although the technique of laminoplasty is effective, a simple and reliable method of holding the posterior elements open has not been described. Methods Ten myelopathic patients with multilevel cervical canal stenosis secondary to spondylosis or ossification of the posterior longitudinal ligament were treated with an expansive open‐door laminoplasty. The posterior elements were stabilized in the open position with titanium miniplates. Computer‐assisted morphometric analysis was performed on preoperative and postoperative computed tomography scans to obtain spinal canal dimensions. Plain radiographs were used to monitor construct integrity. Results The preoperative sagittal canal diameter was 8.2 ± 0.96 mm, and the canal area was 180.6 ± 33.7 mm2. These dimensions increased after surgery to 16.6 ± 1.5 mm and 321.9 ± 29.7 mm2, respectively. The titanium miniplate constructs did not fail during the follow‐up period (mean, 26.4 months), and the decompression was maintained. The single significant complication was a transient C5 radiculopathy. Conclusions Normal canal dimensions can be reestablished with open‐door laminoplasty. Achieving and maintaining an increased sagittal canal diameter is probably the most important change in anatomic parameters to facilitate neurologic recovery. The use of titanium miniplates to stabilize the posterior elements after laminoplasty is a simple, durable, and effective technique to maintain the increased sagittal diameter of the spinal canal.

Spinal cord infarction following therapeutic computed tomography-guided left L2 nerve root injection.

Study Design. Case report. Objectives. To report a rare case of spinal cord infarction following therapeutic computed tomography-guided nerve root injection. Summary of Background Data. Diagnostic and therapeutic image-guided nerve root injection is commonly performed in the management of low back pain and sciatica. The severe complication of spinal cord infarction has been reported in only 3 cases previously. Methods. Retrospective review of case records and imaging. Results. A 71-year-old woman presented with symptoms and signs of left L2 nerve root compression. She was managed with computed tomography-guided left L2 nerve root injection using bupivacaine and triamcinolone and developed immediate bilateral sensory loss and paraplegia. Magnetic resonance imaging demonstrated diffuse hyperintensity within the distal thoracic cord and conus on T2-weighted images, consistent with spinal cord infarction. Conclusions. We report the fourth case of spinal cord infarction following nerve root injection. The severity of this complication warrants that it should be considered during patient consent for this procedure.

Benign central neurocytoma

“Central neurocytoma” is classically considered as an intraventricular benign tumor, largely based on data from small retrospective series. The authors present prospective data on 12 patients with tumors diagnosed as central neurocytoma, to highlight the diverse nature of this tumor and challenge the classic notion.

Quality of life assessment using the Short Form-12 (SF-12) questionnaire in patients with cervical spondylotic myelopathy: Comparison with SF-36

Study Design. Clinical outcome study comparing the Short Form-36 (SF-36) and Short Form-12 (SF-12) assessment scales in patients with cervical spondylotic myelopathy (CSM). Objectives. To compare the validity, reliability, and sensitivity to change of the SF-12 and SF-36 scales in CSM patients undergoing decompressive surgery. Summary of Background Data. The SF-36 is a generic Health Related Quality of Life (HRQoL) questionnaire, consisting of 36 questions that can be reported as a Physical (PCS) and Mental Component Summary (MCS). Recently, an abbreviated version of SF-36, the SF-12, which uses only 12 questions drawn from the SF-36, has been described. Methods. In this prospective study, patients with CSM undergoing decompressive surgery, self-completed the SF-36 questionnaire before surgery and at 6 months after surgery. SF-12 item responses were abstracted from the responses given to the SF-36 questionnaire. The validity, reliability, and sensitivity to change of the PCS and MCS components of SF-12 and SF-36 scales were compared. Results. Overall, 105 patients underwent anterior (N = 58) or posterior (N = 47) decompressive surgery. After surgery, there were improvements in the PCS components of both the SF-36 (40 ± 2 to 54 ± 2) and SF-12 (34 ± 2 to 48 ± 3), as well as in the MCS component of the SF-36 (48 ± 2 to 63 ± 2) and SF-12 (43 ± 2 to 59 ± 2) (P < 0.001). The sensitivity to change and absolute sensitivity for both SF-12 and SF-36 were comparable, but the reliability of SF-36 was marginally greater. There were close and linear correlations between the SF-36 and SF-12 scores for both the PCS and MCS components, before and after surgery (R = 0.86 to 0.93; P < 0.0001). Conclusions. Both the SF-12 and SF-36 scales are valid and sensitive to changes in physical and mental health status in CSM patients, undergoing decompressive surgery. Despite its abbreviated nature, the SF-12 appears to be an adequate substitute for SF-36, and its brevity should increase its attractiveness to both clinicians and patients.

Postoperative spinal epidural hematoma (SEH): incidence, risk factors, onset, and management

BACKGROUND CONTEXT Spinal epidural hematoma (SEH) is a rare, yet potentially devastating complication of spinal surgery. There is limited evidence available regarding the risk factors and timing for development of symptomatic SEH after spinal surgery. PURPOSE To assess the incidence, risk factors, time of the onset, and effect of early evacuation of symptomatic SEH after spinal surgery. STUDY DESIGN Multicenter case control study. PATIENT SAMPLE All patients who underwent open spinal surgery between October 1, 1999, and September 30, 2006, at the National Hospital For Neurology and Neurosurgery (NHNN) and the Wellington Hospital (WH) were reviewed. OUTCOME MEASURES Frankel grade. METHODS Patients who developed SEH and underwent evacuation of the hematoma were identified. Two controls per case were selected. Each control had undergone a procedure with similar complexity, at the same section of the spine, at the same hospital, and under the same surgeon within 6 months of the initial operation. RESULTS A total of 4,568 open spinal operations were performed at NHNN and WH. After spinal surgery, 0.22% of patients developed symptomatic SEH. Alcohol greater than 10 units a week (p=.031), previous spinal surgery (p=.007), and multilevel procedures (p=.002) were shown to be risk factors. Initial symptoms of SEH presented after a median time of 2.7 hours (interquartile range [IQR], 1.1-126.1). Patients who had evacuation surgery within 6 hours of the onset of initial symptoms improved a median of 2 (IQR, 1.0-3.0) Frankel grades, and those who had surgery more than 6 hours after the onset of symptoms improved 1.0 (IQR, 0.0-1.5) Frankel grade, p=.379. CONCLUSIONS Symptomatic postoperative SEH is rare, occurring in 0.22% of cases. Alcohol consumption greater than 10 units a week, multilevel procedure, and previous spinal surgery were identified as risk factors for developing SEH. Spinal epidural hematoma often presents early in the postoperative period, highlighting the importance of close patient monitoring within the first 4 hours after surgery. This study suggests that earlier surgical intervention may result in greater neurological recovery.

Sellar tuberculoma : Report of two cases

SummaryHypophyseal tuberculomas are exceptionally rare. We report two patients with sellar tuberculoma but with no evidence of concurrent extrasellar disease. Although the lesion is often mistaken for adenoma, there are characteristic radiological features: intense enhancement on contrast CT and thickening of the pituitary stalk on MRI in 86% of cases. Accurate diagnosis is important because pituitary tuberculoma is curable.

Dynamic degenerative lumbar spondylolisthesis: diagnosis with axial loaded magnetic resonance imaging.

Study Design. Retrospective review of case notes and imaging. Objective. To show the advantage of axial loaded magnetic resonance imaging (MRI) for identification of dynamic degenerative spondylolisthesis as a suspected cause of spinal claudication. Summary of Background Data. Degenerative spondylolisthesis typically occurs at L4/L5 and is usually evident on plain radiography. However, dynamic degenerative spondylolisthesis may become evident on erect radiographs when not shown on supine radiographs or MRI. Methods. The case notes and imaging (radiography, conventional MRI, and axial loaded MRI) in 2 patients with symptoms of spinal claudication were reviewed. Results. A 44-year-old female presented with a 3-year history of intermittent low back pain and right leg numbness after a fall. A 52-year-old female presented with a 4-year history of low back pain, bilateral leg weakness, and right leg numbness. In both cases, conventional MRI studies showed mild-to-moderate degenerative disc disease only with no evidence of abnormal spinal alignment or nerve root compression. Axial loaded MRI clearly showed the development of a degenerative spondylolisthesis with central canal stenosis and facet ganglion formation in 1 case. Conclusions. Axial loaded MRI identified occult dynamic degenerative spondylolisthesis, which correlated with the clinical picture but was not shown on initial conventional MRI or plain radiography.

Variation of the groove in the axis vertebra for the vertebral artery

Transarticular screws at the C1 to C2 level of the cervical spine provide rigid fixation, but there is a danger of injury to a vertebral artery. The risk is related to the technical skill of the surgeon and to variations in local anatomy. We studied the grooves for the vertebral artery in 50 dry specimens of the second cervical vertebra (C2). They were often asymmetrical, and in 11 specimens one of the grooves was deep enough to reduce the internal height of the lateral mass at the point of fixation to < or =2.1 mm, and the width of the pedicle on the inferior surface of C2 to < or =2 mm. In such specimens, the placement of a transarticular screw would put the vertebral artery at extreme risk, and there is not enough bone to allow adequate fixation. Before any decision is made concerning the type of fixation to be used at C2 we recommend that a thin CT section be made at the appropriate angle to show both the depth and any asymmetry of the grooves for the vertebral artery.

The use of autologous skull bone grafts for posterior fusion of the upper cervical spine in children.

Study Design. Traditionally bone grafts used in posterior cervical fusion have been harvested from the iliaccrest, rib, tibia, or fibula. Their use is not without significant morbidity, and it is often difficult to harvest suitable quantities of good quality bone in children. We have used autologous calvarial bone secured by sublaminar wires in seven patients with congenital spinal anomalies to achieve craniocervical stabilization and fusion. Objectives. To detail our experiences with this new method of harvesting autologous bone grafts from the patients skull for occipitocervical fusion in a pediatric practice. Summary of Background Data. Calvarial bone has been used extensively in craniofacial reconstructive work with good long-term results and with no significant bone resorption. The use of membranous bone is supported by several basic science studies reported in the plastic surgery literature that claim a superiority over endochondral bone regarding fusion. In the present study, autologous calvarial bone has been used in the treatment of seven cases of congenital upper cervical spine instability associated with neurologic deficit. This method circumvents many of the problems attached to the use of traditional donor sites and provides good quality bone in large quantity that can be specifically tailored to match the contours of the craniocervical junction. Method. We used autologous calvarial bone secured by sublamlnar wires in seven children with congenital spinal anomalies to achieve craniocervical stabilization and fusion. The ensuing calvarial defect was repaired using split-thickness parietal bone with the bone graft graft, which was ultimately used for the cervical fusion and acted as a templete to obtain a mirror image and exact match to achieve good cosmetic results. The patients were immobilized after surgery in a halo orthosis for 3 months. Results. Satisfactory results (100% fusion) were achieved in all seven cases with no attendant morbidity related to the method of graft procurement. Conclusions. We recommend this technique as a safe and effective alternative to the more traditional means of graft procurement previously used in cases of craniocervical instability in children.