The accuracy of pedicle screw placement in thoracic spine using the Funnel technique in idiopathic scoliosis.

STUDY DESIGN: A retrospective study of the accuracy of the pedicle screw placement in the thoracic spine using the Funnel technique in idiopathic scoliosis was conducted by using CT-scan analysis. OBJECTIVE: To evaluate the accuracy of thoracic pedicle screw placement using the Funnel technique in the surgical management of idiopathic scoliosis. BACKGROUND DATA: Placement of thoracic pedicle screw especially in idiopathic scoliosis is technically challenging. CT scan navigator is time-consuming and very expensive. Funnel technique was developed to locate the position of the pedicle and without using the CT guided navigator. There are no reports on the accuracy of pedicle screw instrumentation of the thoracic spine using the funnel technique in scoliosis surgery. MATERIAL AND METHOD: 117 screws in 14 patients with idiopathic scoliosis were investigated by computed tomography. Screw positioning was analyzed based on each spinal level, side of deformities (convex or concave side) and direction of cortical penetration. RESULT: Forty-one screws (35%) were placed within the pedicle. Forty-five screws (38%) breeched the medial cortex of pedicle and thirty-one screws (27%) breeched the lateral cortex of pedicle. The percentage of screws totally contained within the pedicle also varied by the thoracic regions: 43% was in between T1-T4, 29% was in between T5-T8, and 37% was in between T9-T12 level. However, there was no statistical difference between the spinal regions and the accuracy rate. Fifty-four screws were placed on the convex side of the spine and sixty-three screws were placed on the concave side. The percentage of totally contained within the pedicle in the convex and the concave side were 20% and 48% respectively. It had statistical difference (p = 0.004). Although medial perforation of the pedicle wall occurred in 38%, there were only 6.7% (3/45) of these that had canal encroachment of more than 4 mm. All of these occurred on the convex side. 62% and 31% of screws with medial perforation were less than 2 mm and 2.0-4.0 mm of canal intrusion respectively. Among the lateral penetration, 42% of these screws penetrated < 2 mm., 48% penetrated 2.0-4.0 mm., and 10% penetrated more than 4 mm. There was 3.4% (4/117 screws) that did not purchase the anterior portion of vertebral body. Although the percentage of totally contained screws was low, there was an 82.1% acceptable rate of screw position. These are screws that were fully contained within the pedicle plus medial perforation less than 2 mm (plus screws that had lateral penetration but purchased into the vertebral body). No screws perforated the anterior cortex of the vertebral body. There were no neurovascular complications. CONCLUSION: Placement of the thoracic pedicle screws using the Funnel technique in idiopathic scoliosis had an accuracy of 82. 1% (screws that were in acceptable position). There were no neurovascular related-complications by using this technique in the present study.

Spinal morphine for post-operative analgesia after lumbar laminectomy with fusion.

BACKGROUND: Intrathecal administration of preservative free morphine (spinal morphine) provides excellent post-operative analgesia. Since the dura is readily accessible by the surgeon during lumbar spinal surgery, it would be convenient and attractive to administer morphine into the spinal space to provide adequate post-operative analgesia in these patients. METHOD: A prospective randomized controlled study evaluated the post-operative analgesic effect of spinal morphine after lumbar laminectomy with fusion. Forty patients were randomly allocated to two groups, morphine (MO) or normal saline (NSS). Morphine 0.3 mg in normal saline 0.3 ml or normal saline 0.3 ml was injected into the dural sac under direct visualization before closing the wound. An intravenous PCA morphine device was provided for post-operative pain relief. RESULTS: Median visual analog scale (VAS) pain scores were lower in the MO group at 2, 4, 24 and 48 h after surgery (1, 1, 2.75 and 1.5 cm in the MO group vs 4.25, 4.25, 5 and 4 cm in the NSS group) (p < 0.05). The time to first patient control analgesia (PCA) demand was delayed in the MO group (131.7 min vs 29.6 min) (p < 0.05). The cumulative doses of PCA morphine consumption were lower in the MO group in the first 24 h and 24-48 h (13.7 and 15.9 mg vs 41.3 mg and 27.1 mg) (p < 0.001). The incidence of pruritus was higher in the MO group in 24 h and 24-48 h (45%, and 45% vs 5% and 10%) (p < 0.05). The incidence and severity of nausea, vomiting and sedation were not different. No patient developed respiratory depression or postdural puncture headache (PDPH). The patients' satisfaction with post-operative pain management was 100 per cent in the MO group and 85 per cent in the NSS group. CONCLUSION: Spinal morphine improved post-operative pain relief after lumbar laminectomy.