Akwasi Boah

Utility of the LevelCheck Algorithm for Decision Support in Vertebral Localization.

Study Design. An automatic radiographic labeling algorithm called “LevelCheck” was analyzed as a means of decision support for target localization in spine surgery. The potential clinical utility and scenarios in which LevelCheck is likely to be the most beneficial were assessed in a retrospective clinical data set (398 cases) in terms of expert consensus from a multi-reader study (three spine surgeons). Objective. The aim of this study was to evaluate the potential utility of the LevelCheck algorithm for vertebrae localization. Summary of Background Data. Three hundred ninety-eight intraoperative radiographs and 178 preoperative computed tomographic (CT) images for patients undergoing spine surgery in cervical, thoracic, lumbar regions. Methods. Vertebral labels annotated in preoperative CT image were overlaid on intraoperative radiographs via 3D-2D registration. Three spine surgeons assessed the radiographs and LevelCheck labeling according to a questionnaire evaluating performance, utility, and suitability to surgical workflow. Geometric accuracy and registration run time were measured for each case. Results. LevelCheck was judged to be helpful in 42.2% of the cases (168/398), to improve confidence in 30.6% of the cases (122/398), and in no case diminished performance (0/398), supporting its potential as an independent check and assistant to decision support in spine surgery. The clinical contexts for which the method was judged most likely to be beneficial included the following scenarios: images with a lack of conspicuous anatomical landmarks; level counting across long spine segments; vertebrae obscured by other anatomy (e.g., shoulders); poor radiographic image quality; and anatomical variations/abnormalities. The method demonstrated 100% geometric accuracy (i.e., overlaid labels within the correct vertebral level in all cases) and did not introduce ambiguity in image interpretation. Conclusion. LevelCheck is a potentially useful means of decision support in vertebral level localization in spine surgery. Level of Evidence: N/A

Clinical outcomes following sublaminar decompression and instrumented fusion for lumbar degenerative spinal pathology

Traditional treatment for lumbar stenosis with instability is laminectomy and posterolateral arthrodesis, with or without interbody fusion. However, laminectomies remove the posterior elements and decrease the available surface area for fusion. Therefore, a sublaminar decompression may be a preferred approach for adequate decompression while preserving bone surface area for fusion. A retrospective review of 71 patients who underwent sublaminar decompression in conjunction with instrumented fusion for degenerative spinal disorders at a single institution was performed. Data collected included demographics, preoperative symptoms, operative data, and radiographical measurements of the central canal, lateral recesses, and neural foramina, and fusion outcomes. Paired t-tests were used to test significance of the outcomes. Thirty-one males and 40 females with a median age 60years underwent sublaminar decompression and fusion. A median of two levels were fused. The mean Visual Analog Scale pain score improved from 6.7 preoperatively to 2.9 at last follow-up. The fusion rate was 88%, and the median time to fusion was 11months. Preoperative and postoperative mean thecal sac cross-sectional area, right lateral recess height, left lateral recess height, right foraminal diameter, and left foraminal diameter were 153 and 209mm(2) (p<0.001), 5.9 and 5.9mm (p=0.43), 5.8 and 6.3mm (p=0.027), 4.6 and 5.2mm (p=0.008), and 4.2 and 5.2mm (p<0.001), respectively. Sublaminar decompression provided adequate decompression, with significant increases in thecal sac cross-sectional area and bilateral foraminal diameter. It may be an effective alternative to laminectomy in treating central and foraminal stenosis in conjunction with instrumented fusion.

Cervical spinal cord herniation

A 73-year-old woman, status post anterior cervical discectomy and fusion 13 years ago for cervical stenosis, presented with rapidly worsening pain and weakness in the bilateral upper and lower extremities. A computed tomography myelography revealed transdural spinal cord herniation at C4–C5 (Fig. 1A, B). Magnetic resonance imaging showed myelomalacia and tethering of the spinal cord anteriorly at the C4–C5 levels, (Fig. 1C, D). The patient underwent an anterior C4 and C5 corpectomy, intradural spinal cord untethering, anterior cervical duraplasty, and placement of a titanium cage and plate from C3 to C6, followed by posterior instrumented fusion from C2 to T2. Postoperative magnetic resonance imaging and X-ray showed intact surgical hardware with untethering of the cervical spinal cord (Fig. 2). Three months postoperatively, the patient has made a significant recovery with improvement in ambulatory function. Spinal cord herniation is rare and often misdiagnosed. The exact pathogenesis is unknown but is thought to be due to an anterior dural defect [1,2]. Patients generally present with progressive myelopathy and with those who experience neurologic deficits, surgical correction using intraoperative monitoring can lead to remarkable improvement [1–5].

Traumatic atlantooccipital dissociation.

A 38-year-old woman presented to our clinic after a highspeed motor vehicle accident. Extrication at the scene was prolonged, and she sustained an incomplete spinal cord injury characterized by right-sided hemiparesis. Imaging revealed atlantooccipital dissociation with bilateral non-displaced C1 lateral mass fractures without C1 arch involvement and a basion-dental interval of 13 mm (Fig. 1A and B). The occipital condyle-C1 interval was determined bilaterally and the condylar sum was found to be 10 mm (Fig. 1G and H). The Powers ratio was determined to be 1.1 (Fig. 1C). Magnetic resonance imaging demonstrated complete tearing of the tectorial membrane (Fig. 1D) and left alar ligament (Fig. 1E), as well as partial tear of the right alar ligament (Fig. 1F). The patient then underwent occiput to C2 fixation (Fig. 2). Three months postoperatively, she was able to move her left upper and lower extremity, with increased strength.

Epidural spinal compression as an initial presentation of Hodgkin lymphoma

Classical Hodgkin lymphoma (CHL) commonly arises in lymph nodes and initial presentation with extranodal disease is rare. We report a patient who presented with progressively worsening back pain, lower extremity weakness and numbness concerning for a myelopathic process of uncertain etiology. MRI revealed an epidural soft tissue mass with cord displacement, for which she underwent resection. Histological analysis of the surgical specimen demonstrated CHL. Further investigation revealed an anterior mediastinal mass, consistent with spread from a more typical location.

Spine and lower extremity kinematics during gait in patients with cervical spondylotic myelopathy

BACKGROUND CONTEXT Cervical spondylotic myelopathy (CSM) typically manifests with a slow, progressive stepwise decline in neurologic function, including hand clumsiness and balance difficulties. Gait disturbances are frequently seen in patients with CSM, with more advanced cases exhibiting a stiff, spastic gait. PURPOSE To evaluate the spatiotemporal parameters and spine and lower extremity kinematics during the gait cycle of adult patients with CSM before surgical intervention. STUDY DESIGN Prospective cohort study. PATIENT SAMPLE Twenty-eight subjects with symptomatic CSM who have been scheduled for surgery and 30 healthy controls (HC). OUTCOME MEASURES Spine and lower extremity kinematics and spatiotemporal parameters. METHODS Clinical gait analysis was performed for patients with CSM and HC. The data were analyzed with a one-way analysis of variance. RESULTS Patients with CSM have significantly more anterior pelvis tilt (CSM: 13.97°, HC: 5.56°), larger lumbar lordosis (CSM: 8.59°, HC: 2.7°), smaller cervical lordosis (CSM: 6.02°, HC: 11.35°), and less head flexion (CSM: 0.69°, HC: 8.66°) at the beginning of the gait cycle. There was a decrease in knee range of motion in patients with CSM compared with controls (CSM: 36.31°, HC: 50.17°). Furthermore, patients with CSM presented with slower walking speed (CSM: 0.81 m/s, HC: 1.05 m/s), decreased cadence (CSM: 95.57 step/m, HC: 107.64 step/m), increased double support time (CSM: 0.40 s, HC: 0.28 s) and stride time (CSM:1.28 s, HC: 1.13 s), shorter stride length (CSM: 1.04 m, HC: 1.18 m) and step length (CSM:0.51 m, HC: 0.58 m), and wider width (CSM: 0.14 m, HC:0.11 m). CONCLUSIONS Our study shows that patients with CSM enter the gait cycle with a larger anterior pelvic tilt and lumbar lordosis as well as less cervical lordosis and head flexion. As a consequence of these abnormal spinal parameters at the onset of the gait cycle, lower extremity biomechanics are also altered. Our study is the first to demonstrate the relationship between aberrant spinal alignment and lower extremity function. Identification of this interrelationship as well as the specific gait and biomechanical disturbances seen in myelopathic patients can both inform our understanding of the disease and tailor rehabilitation protocols.