Design of study: Prospective, observational

Purpose of the study: Obese and morbidly obese patients undergoing lumbar surgery can be a challenge to the operating surgeon. Reports on the perioperative data in this group of patients are scarce. The purpose of the study is to prospectively compare the perioperative data in patients with normal and high BMI, undergoing lumbar spine surgery.

Method: We conducted a prospective audit of 50 consecutive patients who underwent primary discectomy or single level decompression under the care of single spine surgeon. Initial Low Back Outcome Score, length of incision, distance from skin to spinous process, distance from skin to lamina, length of hospital stay, blood loss and complications were studied in detail.

Results: We used student t test to compare the two groups and Pearson Correlation to correlate the data against high BMI. We were unable to demonstrate a statistically significant difference between those with normal BMI and high BMI in any of the above parameters analysed.

Conclusion: A high BMI was not associated with an increased perioperative morbidity in this patient group. Contrary to other areas of orthopaedic surgery, there is no statistically significant difference in the Initial Low Back Outcome Score and perioperative data between patients with normal and high BMI undergoing lumbar discectomy and single level decompression.

Conflict of Interest: None

Source of Funding: None

Background context: It is frequently stated that referred pain does not travel below the knee. However, for many years studies provoking referred pain have demonstrated pain radiating below the knee.

Methods: Over a twelve month period, 643 patients with mechanical back pain and 185 patients with nerve root compressions were seen. For each patient two body map images (front and back) were obtained. Some patients attended for review, at a minimum of six weeks after their first visit. These images were also analysed.

Composite images were created by combining all images from patients in one diagnosis group. Colour based overlays were used to analyse the body map images, to locate the locations of pain. Colour density was scaled so that the site with the most hits had a pure colour, reducing down to zero colour for sites with no hits.

Results: There were 720 nerve root compression images. 216 (30%) showed no leg pain, 91 (12.6%) showed upper leg pain, 134 (18.6%) showed lower leg pain and 279 (38.8%) showed upper and lower leg pain.

There were 1964 mechanical back pain images. 674 (34.3%) showed no leg pain, 528 (26.9%) showed upper leg pain, 308 (15.7%) showed lower leg pain and 454 (23.1%) showed upper and lower leg pain.

Conclusion: A large proportion (39%) of the mechanical back pain images indicated that the patient experienced referred pain below the knee. This has significant implications in the diagnosis of nerve root compressions, potentially leading to inappropriate surgery.

Conflicts of Interest: None

Source of Funding: None

Aim: The aim is to assess the accuracy of post-contrast imaging in identifying recurrent disc prolapse (RDP).

Material and methods: 246 revision discectomies performed between January 1994 and June 2004 were considered. Of these, for 192 LIRDs, post-contrast scans (95 CTs and 97 MRIs) within 6 months of operation, and adequate operation records were available. Original scan reports and scan interpretation of an independent observer were taken into account.

Results: Of 95 post-contrast CTs, 88 showed RDP (29 large-contained, 12 large-sequestrated, 39 moderate-contained, and 8 small-contained), 2 hypertrophic epidural scar (HES), and 5 lateral recess stenosis but no RDP or HES. From operation records, 30 of these 88 were found to have HES, but no RDP. Also, operation records confirmed presence of RDP in 21 of 29 large-contained (72.4%), 10 of 12 large-sequestrated (83.3%), 16 of 39 moderate-contained (41%) and 2 of 8 small-contained (25%). Of the 5 which did not show RDP, 2 (40%) were found to have RDP (1 moderate-contained and 1 large-contained) during operation.

Of 97 post-contrast MRIs, 85 showed RDP (18 large-contained, 22 large-sequestrated, 26 moderate-contained,4 moderate-sequestrated,13 small-contained, and 2 small-sequestrated), 5 HES, and 7 lateral recess stenosis but no RDP or HES. From operation records, 31 of these 85 were found to have HES, but no RDP. Also, operation records confirmed presence of RDP in 10 of 18 large-contained (55.6%), 19 of 22 large-sequestrated (86.4%), 8 of 26 moderate-contained (30.8%), 4 of 4 moderate-sequestrated (100%), 6 of 13 small-contained (46.2%) and 1 of 2 small-sequestrated (50%). Of the 7 which did not show RDP, 1 (14.3%) was found to have moderate-contained RDP during operation.

Conclusion: Accuracy of post-contrast scans is proportional to the size of RDP. MRI has high accuracy for sequestrated RDP.

Aim: The aim is to correlate intra-operative findings such as epidural fibrosis (EF), size and type of disc fragment, lateral recess stenosis and dural tear with postoperative residual radiculopathy (RR) and residual low back pain (RLBP).

Material and Methods: 246 revision discectomies performed between January 1994 and June 2004 were considered, of which adequate records were available for 215 (201 ipsilateral and 14 contralateral). Of 201 LIRDs, 85 were at L5S1, 101 at L45, 10 at L5S1+L45, 3 at L34 and 2 at L23 level. Patients who had had fusion or instrumentation in addition to LIRD were excluded. For 201 LIRDs average follow-up was 18.5 months (range −1 to 96 months) and 100 LIRDs had a minimum of 12 months’ follow-up.

Results: Of the 179 first-time LIRDs, 65 (36.3%) had significant RR, 73 (40.8%) significant RLBP, 3 (1.7%) cauda equina syndrome, 2 (1.1%) infective discitis, and 1 (0.6%) foot-drop. Of the 21 second-time LIRDs, 15 (71.4%) had significant RR, 17 (81%) significant RLBP, 2 (9.5%) infective discitis and 1 (4.8%) cauda equina syndrome. EF was classified as abundant, moderate and scant. Incidence of RR and RLBP was proportional to amount of EF and size of hypertrophic scarred ‘disc’ bulge, but it correlated poorly with size of ‘soft’ disc prolapse. Lateral recess decompression in addition to LIRD did not significantly alter the incidence of RR and RLBP.

25 (12.4%) patients who had dural tear had worse results.

Conclusions: Large proportion of LIRDs result in significant residual symptoms. Second-time LIRDs have higher complication rates and even poorer outcomes.