ABSTRACT
Background: Free-hand and fluoroscopic-guided pedicle screw placement has been associated with higher rates of pedicle breaches (frequency range 15-40% especially in deformed pedicles). Neurological complications are more "critical" (i.e., frequent and significant) with medial and inferior pedicle-wall breaches due to the proximity of the neural elements. Here, we analyzed the effectiveness of O-arm navigation in minimizing "critical" pedicle wall breaches and their complications in 21 complex spinal deformity cases. Methods: Twenty-one complex spinal deformity cases were prospectively managed with O-arm-navigated posterior-instrumented fusions. Preoperative assessment included; evaluation of the type of scoliosis, the magnitude of the deformity, and the anatomy of the pedicles - (i.e., classified using Watanabe et al.). The O-arm was used to confirm and grade both the intraoperative and postoperative location of screws. Other variables analyzed included; duration of surgery, estimated blood loss, complications, and radiation exposure. Results: In 21 patients, 259 (63.45%) of 384 pedicles were instrumented; we observed 22 of 259 pedicle screw breaches. Significant (>2 mm) breaches were observed in two medial and one inferior wall cases that required revision; the overall biomechanically significant screw breach rate was (3/259) 1.2% with an accuracy rate of 98.8%. Pedicle screw placement resulted in another 14 nonsignificant (<2 mm) breaches; ten were medial and four involved the inferior wall. As anterior, lateral, and "in-out-in" trajectory pedicle screws beaches were nonsignificant, they were not included in our analysis. Conclusion: O-arm navigation decreased the incidence of medial and inferior (i.e., >2 mm "critical") pedicle screw breaches applied in 21 patients with deformed pedicles due to scoliosis. Further, the O-arm minimized the operating time, decreased the estimated blood loss, and reduced the incidence of complications.
ABSTRACT
CASE: A 33-year-old woman with back pain and radiculopathy had presented with bilateral ankle weakness. MRI showed an intramedullary conus lesion suggestive of neoplasm, but posterior midline durotomy revealed only pus. Pus samples showed Staphylococcus aureus, which was treated with 6 weeks of antibiotics. Two-year follow-up showed complete neurological recovery with no clinicoradiological signs of recurrence. CONCLUSION: Usually, intramedullary spinal cord abscess (ISCA) has an acute presentation and warrants an emergent line of treatment with a risk of mortality. Very rarely chronic ISCA can mimic intramedullary spinal cord tumor. It is the first case reported in the literature of chronic ISCA mimicking conus IMST.
