Purpose

To compare the incidence and nature of ‘neurophysiological events’ identified, post hoc, by a consultant neurophysiologist with those identified intra-operatively by clinical physiologists, before and after intervention(s).

Study Design: Prospective cohort study.

Objective: To assess the safety and efficacy of an intra-operative gamma probe in the surgical treatment of osteoid osteomas and osteoblastomas arising from the spine.

Summary of background data: Spinal osteoid osteomas and osteoblastomas are difficult to localise and may present adjacent to neural structures. Complete surgical excision of the nidus is a pre-requisite for curative resection.

Methods: All patients with a presumptive diagnosis of osteoid osteoma or osteoblastoma were investigated with plain radiography, computed tomography, magnetic resonance imaging and a technitium bone scan. Nine patients underwent surgical excision. 600 MBq of 99m technitium HMDP was administered intravenously three hours prior to surgery. A sterile cadmium telluride detector connected to a digital counter/ratemeter was used to detect gamma radiation emitted by the tumour intra-operatively to assist with localisation and confirmation of complete excision.

Results: Between October 1995 and September 2006, nine patients required surgical excision for seven osteoid osteomas and two osteoblastomas arising from the spine. All patients were between the ages of 9–31 years and presented with back or neck pain. All tumours involved the posterior elements of the spine. Three patients had previous failed treatment including CT-guided radiofrequency ablation and surgical excision. In all cases the counts per second (cps) dropped significantly following excision. For the osteoid osteoma cases, the mean cps dropped from 203.8 (range 60–515) to 72.5 cps (range 10–220) post-excision. For the osteoblastoma cases the mean cps dropped from 373.5 (range 67–680) to 40.5 cps (range 16–65) post-excision. Histological examination confirmed complete excision in all cases. The mean follow-up was 4.5 years (range 0.5 – 11 years). All patients reported disappearance of the characteristic pre-operative pain.

Conclusions: The use of an intra-operative gamma probe helps to localise and confirm complete excision of osteoid osteoma and osteoblastoma arising from the spine. Accurate localisation results in safe excision with maximal conservation of surrounding normal bone, whilst minimising operative time, blood loss, hospital stay and risk of recurrence.

Objective: Surgical correction of late-onset idiopathic scoliosis (AIS) has been shown to be effective in obtaining correction in the frontal and sagittal planes, but is of questionable benefit in reducing the rib hump in the transverse plane The purpose of this study was to assess the effects of double rod and pedicle screw (AO USS) instrumentation on transverse plane asymmetry (on the convex and concave side of the scoliosis) in a single thoracic curve type (King III).

Design: A consecutive, prospectively studied cohort treated by a single surgeon with either a single-stage or two-stage procedure.

Subjects: Sixty-five patients with a King III adolescent idiopathic scoliosis were studied. There were 53 females and 12 males whose mean age at surgery was 14.5 years (range 11.1 to 17.9). A single-stage posterior fusion with instrumentation was performed in 46 patients whose mean Cobb angle at surgery was 56° (range 35 to 84). A two-stage procedure with thoracotomy and anterior spine release by multiple disc excisions (mean 6 levels) combined with internal costoplasty (mean 6 ribs), followed one week later by posterior spinal fusion with instrumentation, was performed in 15 patients whose mean Cobb angle was 78° (range 40 to 92).

Outcome measures: All patients were assessed both radiographically and by Integrated Shape Imaging System (ISIS) surface topography pre-operatively, postoperatively (mean of 14 weeks) and at follow-up visits for a mean 2.7 years (range 1.5–6.1).

Results: There were no non-unions or instrument failures in either group.

Single-stage group: Post-operative improvement in the Cobb angle was a mean 54% with a mean 2° loss in correction at final follow-up. ISIS showed the angle of rib hump elevation (convexity side) was improved by a mean of 2.1° and the angle of rib depression (concavity side) was unchanged. At final follow-up the angle of rib hump elevation had recurred by a mean of 3.6° beyond the original pre-operative value. The angle of rib depression remained unchanged.

Two-stage group: Post-operative improvement in the Cobb angle was a mean 64% with a mean 1° loss in correction at final follow-up. ISIS showed the angle of rib hump elevation (convexity side) was improved by a mean of 6.2° and the angle of rib depression (concavity side) was improved by a mean of 3.5°, producing a more balanced transverse plane. At final follow-up the angle of rib hump elevation only recurred by a mean 2.2°. This was compensated by a further improvement in the angle of rib depression by a mean of 2.5°, producing a further correction to balance the transverse plane.

Conclusions: Single-stage surgery is not effective in improving the transverse plane deformity. Two-stage surgery improves the transverse plane deformity on both the convexity and concavity producing a more balanced spine with further improvement due to an improvement of the rib depression (concave side) during follow-up (growth).