Paraspinal Muscle Sparing Versus Percutaneous Screw Fixation: A Comparative Enzyme Study of Tissue Injury during the Treatment of L4-L5 Spondylolisthesis

OBJECTIVE: Screw fixation via the paraspinal muscle sparing approach and by percutaneous screw fixation are known to diminish the risk of complications, such as, iatrogenic muscle injury as compared with the conventional midline approach. The purpose of this study was to evaluate tissue injury markers after these less traumatic screw fixation techniques for the treatment of L4-L5 spondylolisthesis. METHODS: Twenty-two patients scheduled for posterior lumbar interbody fusion (PLIF) at the L4-L5 segment for spondylolisthesis were prospectively studied. Patients were divided into two groups by screw fixation technique (Group I: paraspinal muscle sparing approach and Group II: percutaneous screw fixation). Levels of serum enzymes representing muscle injury (CK-MM and Troponin C type 2 fast), pro-inflammatory cytokine (IL-8), and anti-inflammatory cytokine (IL-1ra) were analyzed using ELISA techniques on the day of the surgery and 1, 3, and 7 days after the surgery. RESULTS: Serum CK-MM, Troponic C type 2 fast (TNNC2), and IL-1ra levels were significantly elevated in Group I on postoperative day 1 and 3, and returned to preoperative levels on postoperative day 7. No significant intergroup difference was found between IL-8 levels despite higher concentrations in Group I on postoperative day 1 and 3. CONCLUSION: This study shows that percutaneous screw fixation procedure is the preferable minimally invasive technique in terms of minimizing muscle injury associated with L4-L5 spondylolisthesis.

Symptomatic Myelopathy Caused by Ossification of the Yellow Ligament

OBJECTIVE: This study was performed to describe the clinical presentation, surgical outcome in patients with symptomatic myelopathy caused by ossification of the yellow ligament (OYL). METHODS: The authors reviewed consequent 12 patients in whom posterior decompressive laminectomies were performed for OYL from 1999 to 2005. Diagnostic imagings including simple radiographs, computed tomography and magnetic resonance images were performed in each case. The patients were reviewed to evaluate the clinical presentation, surgical outcome and complications of the operation. RESULTS: In all patients, OYL was located in the lower thoracic region and all patients presented with numbness on both limbs and pain. Among them, 5 patients presented with gait disturbance due to paraparesis and two patients had sphincter dysfunction. Decompressive laminectomy through a posterior approach using microscope resulted in improvement of symptoms in all patients, but, recovery was incomplete in a half of the patients. The mean postoperative Japanese orthopaedics association (JOA) score was 7.9 when compared with 4.9 in preoperative assessment and the mean recovery rate was 65%. Dural tear was noticed in four patients, so dural repair was performed, but there were no neurological deficits related to neural injury. CONCLUSION: OYL is an uncommon cause of myelopathy but it can lead to debilitating thoracic myelopathy. Careful decompressive laminectomy can achieve favorable results.

Solitary Lymphoblastic Lymphoma of the Thoracic Spine

Non-Hodgkin's lymphoma rarely originates from bone, and even more infrequently from a vertebral body. Lymphoblastic lymphoma is a rare type of non-Hodgkin's lymphoma, and results from an abnormality in adaptive immune cells. A 27-year-old man presented with a two-month history of night sweats, weight loss, and severe back pain. Radiological studies demonstrated an osteolytic lesion compressing the subarachnoid space at the T11 level. Posterolateral fusion with decompression was performed and a pathologic examination confirmed lymphoblastic lymphoma of the B-cell precursor type. To our knowledge, this is the first report of solitary lymphoblastic lymphoma from B-cell precursors in of the thoracic spine. Herein, we discuss the presenting symptoms and the management of this rare case of lymphoblastic lymphoma.