Micro-Endoscopic Decompression for Lumbar Canal Stenosis - A boon for obese patients

Presented at SMISS Global Forum 2014
By Arvind Kulkarni MS(ORTH) Dip(ORTH) FCPS Dip(SICOT)

Disclosures: Arvind Kulkarni MS(ORTH) Dip(ORTH) FCPS Dip(SICOT) None

Introduction:
Literature shows relatively poor outcomes and increased peri-operative complications in obese patients undergoing decompression surgery for LCS. However, the relationship between body habitus and outcomes after minimally invasive decompression surgery, popularly known as Micro-Endoscopic Decompression (MED) is not well defined.

Aims/Objectives:
The aim of the present study is to determine the influence of body-mass index(BMI) on outcomes of MED for LCS.

Methods:
The study period extended from June2010-June2012. All consecutive patients with symptomatic LCS failing conservative management were considered for surgery. The patients were classified as overweight (BMI>25 kg/m²) and normal (BMI < 25 kg/m²) according to international classification of WHO. All patients underwent MED using the 18mm METRX tubular retractor (Medtronics, Memphis, USA). The central canal and the ipsi-lateral and contra-lateral nerve roots were decompressed using “Wanding” technique through a unilateral approach. The outcomes were assessed using pre-operative and post-operative Oswestry Disability Index(ODI) and Visual Analog Scale(VAS) for leg pain and back pain. The operative time, blood loss, the duration of hospital stay and complications were analysed. The results were also analysed in comparison with the literature representing open surgeries for LCS.

Results:
In all 65 cases were included in the study. Of these 30(40 %) were obese and 35(46.6%) were non-obese.The mean preoperative ODI in obese and non obese patient was of 58.76 and 63.54 and mean postoperative ODI was 19 and 18.45 respectively. The improvement rate in ODI score in the obese group(p value<0.05) and in non-obese group(p value<0.05) is almost similar. In the obese-gp, the mean pre-operative and post-operative VAS score for leg pain was 8 and 0.8 respectively. Similarly in non-obese-gp, pre-operative and post-operative VAS score for leg pain was 5.6 and 1.14 respectively. In obese-gp, the mean preoperative and post-operative VAS score of back pain was 5.05 and 1.3 .Similarly in non-obese gp, the mean pre-operative and post-operative VAS score for back pain was 3.9 and 1.4 . There was no statistically significant difference in the change of ODI scores (p value<0.05) and VAS scores between these groups irrespective of BMI. The mean operative time in obese group was 127 minutes and mean operative time in non-obese group was 111 minutes. Average operative blood loss and length of stay was 82.3 ml and 3.7 days respectively.

Conclusions:
Obese and non-obese patients benefit equally from MED. The authors strongly recommend this minimally invasive procedure(MED) for LCS, especially in obese patients.