**11. Clinical case series**

A retrospective analysis was performed of patients undergoing 3 or more levels of minimally invasive laminectomy for lumbar stenosis as seen in **Figure 10**.

Thirty-three consecutive patients were analyzed with clinical characteristics as seen below (**Table 1**). The most common levels treated are seen in **Table 2** and medical co-morbidities are seen in **Table 3**. The average estimated blood loss was 190 cc. Surgical time averaged 3 hours. Hospital stays averaged 3-4 days. Complications rates were relatively low (**Table 4**). Visual analog score (VAS) back and leg pain and Oswestry disability index (ODI) improved as seen in **Figure 11**. These improvements were found to be statistically significant at 24-month followup compared with pre-operative values. One patient (3%) underwent adjacent level *Minimally Invasive Laminectomy for Lumbar Stenosis with Case Series of Patients… DOI: http://dx.doi.org/10.5772/intechopen.105186*

**Figure 10.**

*Pre and post-operative T2 weighted sagittal and corresponding axial MRI images of patient who underwent L2-3/L3-4/L4-5 minimally invasive laminectomy for stenosis. Note on post-operative MRI preservation of spinous process and paraspinous muscle anatomy while achieving adequate canal decompression.*

### **Table 1.**

*Clinical characteristics of patients undergoing minimally invasive laminectomy (3 or more levels).*


### **Table 2.**

*Levels treated with lumbar stenosis. Most common levels treated were L2-3, L3-4 and L4-5.*


### **Table 3.** *Medical co-morbidities seen in patients treated with 3 or more levels of lumbar stenosis.*

*Minimally Invasive Laminectomy for Lumbar Stenosis with Case Series of Patients… DOI: http://dx.doi.org/10.5772/intechopen.105186*


### **Table 4.**

*Operative characteristics, complication rates, and reoperations of patients undergoing multi-level (3 or more levels) minimally invasive laminectomy for stenosis. There was a relatively low rate of complications in these patients.*

### **Figure 11.**

*Visual analogue score (VAS) back and leg pain and Oswestry disability index (ODI) improved as seen above.*

laminectomy, decompression, and instrumentation for adjacent level disease. This patient had multilevel degenerative disc disease of the lumbar spine. He initially underwent a L2-3, L3-4, and L4-5 MIS laminectomy, fusion, and pedicle screw instrumentation for multi-level stenosis. He subsequently developed L5-S1 lumbar stenosis and underwent adjacent level decompression, fusion and instrumentation. He has since returned to work and has normal activities of daily living. This series shows the benefits of minimally invasive laminectomy for stenosis. We feel that preservation of the normal anatomy (i.e., spinous process and paraspinous muscle) improves long-term outcomes, fusion rates, and complications of patients suffering from lumbar stenosis and reduce adjacent level disease requiring reoperation.
