Minimally invasive procedures on the lumbar spine

Table 1 Differences between outcomes of minimally invasive vs open surgical techniques

MIS techniques	Ref.	Differences in outcome compared to open techniques
Non-fusion techniques
MIS microdiscectomy	Kamper et al[11]	Moderate to low evidence of no differences between MIS and open microdiscectomy No significant differences in QUALYs or total costs MIS took 10-15 min longer, resulted in 52 cc reduction in EBL and reduced mean LOS by 1.5 d
MIS direct decompression (Laminectomy/laminotomy)	Rahman et al[16]	Decreased EBL compared to open technique MIS procedures were 37-47 min shorter Decreased LOS by 2.52 d in patients undergoing decompression at ≤ 2 levels MIS had fewer complications (7.9% vs 16.1%)
	Anderson et al[17]	No significant differences in terms of ODI, Short-Form-12, and VAS
	Khoo et al[18]	Longer operative times in MIS group (109 min vs 88 min) Decreased EBL and postoperative stay in MIS group
	O’Toole et al[21]	0.10% surgical site infection rate Authors concluded that MIS technique may reduce SSI rate by 10-fold
MIS indirect decompression (Interspinous process devices)	Kuchta et al[26]	Statistically significant improvement in symptom severity and physical functioning throughout 2-yr follow-up period
	Bowers et al[27]	85% failure rate and 38% complication rate
	Brussee et al[28]	Poor outcome in 68.9% of patients
	Kim et al[29]	Cost analysis study found devices to be extremely costly and questioned cost-effectiveness
Fusion techniques
Intertransverse onlay fusion	-	No literature available comparing MIS versus open posterolateral onlay fusion
Percutaneous pedicle screw fixation	Lehmann et al[34]1	EBL and muscle damage markers significantly lower in MIS group Compartment pressure, blood flow and EMG readings similar between both groups Radiation exposure greater in MIS group
MIS transforaminal lumbar interbody fusion	Seng et al[51]	Statistically increased fluoroscopic times (55.2 s vs 16.4 s) and operative times (185 min vs 166 min) in MIS group MIS had less EBL than open (127 cc vs 405 cc) Postoperative morphine use less in MIS group (8.5 mg vs 24.2 mg) Shorter LOS in MIS group (3.5 d vs 5.9 d)
	Parker et al[55]	MIS associated with reduction in mean hospital cost of $1758, indirect cost of $8474, total 2-yr social cost of $9295 Similar 2-yr direct health care cost and QALYs gained
MIS direct lateral interbody fusion	Villavicencio et al[73]	Lower complication rate in MIS versus open (8.2% vs 16.7%)
	Rodgers et al[74]	Significantly lower complication rate in MIS cohort (7.5% vs 60%) Decreased EBL, lower transfusion rate and shorter LOS
	Deluzio et al[75]	Average LOS in MIS group 49% shorter Average cost savings for MIS group at 45 d of $2536/patient

¹Animal study. MIS: Minimally invasive surgery; LOS: Length of stay; EBL: Estimated blood loss; ODI: Oswestry Disability Index; VAS: Visual analog scale; SSI: Surgical site infection; EMG: Electromyography; cc: Centimeter cubed; QALY: Quality adjusted life year.