A Prospective, Multi-Institutional Comparative Effectiveness Study of Lumbar Spine Surgery in Morbidly Obese Patients: Does Minimally Invasive TLIF Result in Superior Outcomes

Presented at SMISS Annual Forum 2013
By Owoicho Adogwa MD, MPH
With Robert Isaacs MD, Paul Thompson BSE, Terence Verla BS, Ulysses Null BS, Kemp Knott BS, Jordan Swearingen BS, Kevin Huang BA, Joseph Cheng MD, MS,

Disclosures: Owoicho Adogwa MD, MPH None Robert Isaacs MD A; NuVasive. B; NuVasive, Providence Medical Technology. C; Association for Collaborative Spine Research. D; SafeRay Spine, LLC, SafeWire, LLC, VilaSpine LTD, Vertera Spine, Providence Medical Technol, Paul Thompson BSE None, Terence Verla BS None, Ulysses Null BS None, Kemp Knott BS None, Jordan Swearingen BS None, Kevin Huang BA None, Joseph Cheng MD, MS None,

Background: Obese and morbidly obese patients undergoing lumbar spinal fusion surgery are a challenge to the operating surgeon. Minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) and Open-TLIF have been performed for many years with good results; however, functional outcomes after lumbar spine surgery in this subgroup of patients remain poorly understood. Furthermore, whether MIS-TLIF or open-TLIF for treatment of degenerative disc disease(DDD) or spondylolisthesis (DS) in morbidly obese results in superior post-operative functional outcomes remains unknown.

Methods: A nationwide, multi-institutional, prospective spine outcomes registry was utilized for this study. Enrollment criteria included available demographic, surgical and clinical outcome data. All patients had prospectively collected outcome measures and a minimum 2-year follow-up. The study group included 148 patients undergoing TLIF for degenerative disc disease or spondylolisthesis; 40 patients underwent MIS-TLIF and 108 patients underwent open-TLIF. Patients completed the Oswestry Disability Index (ODI), MOS Short Form 36 (SF-36), and back and leg pain numerical rating scores before surgery, then at 3, 6, 12, and 24 months after surgery. Clinical outcomes and complication rates were compared between both patient cohorts.

Results: Compared to preoperative status, VAS back and leg pain, ODI and SF-36 PCS/MCS were improved in both groups. Both MIS-TLIF and open-TLIF patients showed similar 2-year improvement in VAS for back pain(MIS-TLIF: 2.42 ± 3.81 vs. open-TLIF: 2.33 ± 3.67, p=0.89), VAS for leg pain(MIS-TLIF: 3.77 ± 4.53 vs. open-TLIF: 2.67 ± 4.10 ,p=0.18), Oswestry disability index (MIS-TLIF: 11.61 ± 25.52 vs. open-TLIF: 14.88 ± 22.07 ,p=0.47), and SF-36 PCS MIS-TLIF: 8.61 ± 17.72 vs. open-TLIF: 7.61 ± 15.55, p=0.93), and SF-36 MCS MIS-TLIF: 4.35 ± 22.71 vs. open-TLIF: 5.96 ± 21.09, p=0.69). Post-operative complications rates between both cohorts were also not significantly divergent between both cohorts (12.50% vs. 17.59%, p=0.51).

Conclusion: MIS-TLIF is a safe and viable option for lumbar fusion in morbidly obese patients, and when compared to open-TLIF, resulted in similar improvement in pain and functional disability. Post-operative complications rates between both cohorts were also not significantly divergent.

Table 1: Baseline characteristics and patients undergoing index ALIF or TLIF surgery. Both cohorts were matched at baseline.

 

Combined Cohort(n=148)

MIS TLIF(n=40)

Open-TLIF(n=108)

P=value

Patient Age(years)

56.25 ± 10.91

56.62 ± 11.69

56.12 ± 10.68

0.821

BMI(Kg/m2)

35.32 ± 4.66

34.48 ± 4.39

35.63 ± 4.74

0.167

Male(%)

45.27

50

47

0.489

 

Indication for Surgery(%)

       

Degenerative Disc Disease (DDD)

104(70.27)

27(67.50)

81(75.00)

0.982

Spondylolisthesis

107(72.29)

29(72.50)

78(72.22)

0.973

 

Surgical Levels(n,%)

L1 – L2

35(23.64)

1.0(2.5)

34(31.48)

8.61E-08

L2 – L3

45(30.40)

7.0(17.50)

38(35.18)

0.022

L3 – L4

48(32.43)

7.0(17.50)

41(37.96)

0.009

L4 – L5

107(72.29)

24(60.00)

83(76.85)

0.061

L5 – L1

83(56.08)

21(52.50)

62(57.40)

 0.600

Pre-Op PRO

BP-VAS

7.00 ±  2.44

6.97 ± 2.49

7.00 ± 2.44

0.939

LP-VAS

6.71 ± 2.98

7.07 ± 3.00

6.58 ± 2.98

0.386

SF-36 MCS

39.88 ± 17.67

41.92 ± 16.69

39.11 ± 18.04

0.383

SF-36 PCS

24.53 ± 10.11

24.06 ± 11.25

24.72 ± 9.70

0.740

ODI

49.60 ± 15.59

50.18 ± 16.74

49.15 ± 15.21

0.594

Values given as Mean ± standard deviation. PRO- patient reported outcomes, VAS-Visual Analog Pain Score, ODI-Oswestry Disability Index.