Minimally invasive versus open lumbar spinal fusion: a matched study investigating patient-reported and surgical outcomes

J Neurosurg Spine 36:753–766, 2022

With the expanding indications for and increasing popularity of minimally invasive surgery (MIS) for lumbar spinal fusion, large-scale outcomes analysis to compare MIS approaches with open procedures is warranted.

METHODS The authors queried the Quality Outcomes Database for patients who underwent elective lumbar fusion for degenerative spine disease. They performed optimal matching, at a 1:2 ratio between patients who underwent MIS and those who underwent open lumbar fusion, to create two highly homogeneous groups in terms of 33 baseline variables (including demographic characteristics, comorbidities, symptoms, patient-reported scores, indications, and operative details). The outcomes of interest were overall satisfaction, decrease in Oswestry Disability Index (ODI), and back and leg pain, as well as hospital length of stay (LOS), operative time, reoperations, and incidental durotomy rate. Satisfaction was defined as a score of 1 or 2 on the North American Spine Society scale. Minimal clinically important difference (MCID) in ODI was defined as ≥ 30% decrease from baseline. Outcomes were assessed at the 3- and 12-month follow-up evaluations.

RESULTS After the groups were matched, the MIS and open groups consisted of 1483 and 2966 patients, respectively. Patients who underwent MIS fusion had higher odds of satisfaction at 3 months (OR 1.4, p = 0.004); no difference was demonstrated at 12 months (OR 1.04, p = 0.67). Lumbar stenosis, single-level fusion, higher American Society of Anesthesiologists Physical Status Classification System grade, and absence of spondylolisthesis were most prominently associated with higher odds of satisfaction with MIS compared with open surgery. Patients in the MIS group had slightly lower ODI scores at 3 months (mean difference 1.61, p = 0.006; MCID OR 1.14, p = 0.0495) and 12 months (mean difference 2.35, p < 0.001; MCID OR 1.29, p < 0.001). MIS was also associated with a greater decrease in leg and back pain at both follow-up time points. The two groups did not differ in operative time and incidental durotomy rate; however, LOS was shorter for the MIS group. Revision surgery at 12 months was less likely for patients who underwent MIS (4.1% vs 5.6%, p = 0.032).

CONCLUSIONS In patients who underwent lumbar fusion for degenerative spinal disease, MIS was associated with higher odds of satisfaction at 3 months postoperatively. No difference was demonstrated at the 12-month follow-up. MIS maintained a small, yet consistent, superiority in decreasing ODI and back and leg pain, and MIS was associated with a lower reoperation rate.

The Effect of Older Age on the Perioperative Outcomes of Spinal Fusion Surgery in Patients With Lumbar Degenerative Disc DiseaseWith Spondylolisthesis

Neurosurgery, Volume 87, Issue 4, 1 October 2020, Pages 672–678

Degenerative spondylolisthesis (DS) is often treated with lumbar spinal fusion (LSF). However, there is concern that the morbidity of LSF may be prohibitively high in older adults.

OBJECTIVE: To evaluate the impact of advanced age on the safety of LSF for DS.

METHODS: Patients who underwent LSF for DS were retrospectively identified from National Surgical Quality Improvement Program datasets for 2011 to 2015 using Current Procedural Terminology codes. Data on demographic characteristics, comorbidities, surgical factors, and 30-d morbidity and mortality were collected. Propensity score matching (nearest neighbor) was performed with age (<70 vs ≥70 yr) as the dependent variable and sex, type of fusion procedure, number of levels fused, diabetes, smoking, hypertension, and chronic steroid use as covariates. Outcomes were compared between age <70 and ≥70 groups.

RESULTS: The study cohort consisted of 2238 patients (n=1119, age<70; n=1119, age≥70). The 2 age groups were balanced for key covariates including sex, race, diabetes, hypertension, CHF, smoking, chronic steroid use, type of fusion, and number of levels. Rates of all complications were similar between younger and older age groups, except urinary tract infection, which was more frequent among the ≥70 age group (OR 2.32, P = .009). Further, patients in the older age group were more likely to be discharged to a rehabilitation (OR 2.94, P < .001) or skilled care (OR 3.66, P < .001) facility, rather than directly home (OR 0.25, P < .001).

CONCLUSION: LSF may be performed safely in older adults with DS. Our results suggest older age alone should not exclude a patient from undergoing lumbar fusion for DS.

The ‘Lumbar Fusion Outcome Score’ (LUFOS): a new practical and surgically oriented grading system for preoperative prediction of surgical outcomes after lumbar spinal fusion in patients with degenerative disc disease and refractory chronic axial low back pain

Neurosurg Review (40) pp 67–81, 2017

In order to evaluate the predictive effect of non-invasive preoperative imaging methods on surgical outcomes of lumbar fusion for patients with degenerative disc disease (DDD) and refractory chronic axial low back pain (LBP), the authors conducted a retrospective review of 45 patients with DDD and refractory LBP submitted to anterior lumbar interbody fusion (ALIF) at a single center from 2007 to 2010.

Surgical outcomes – as measured by Visual Analog Scale (VAS/back pain) and Oswestry Disability Index (ODI) – were evaluated pre-operatively and at 6 weeks, 3 months, 6 months, and 1 year post-operatively. Linear mixed-effects models were generated in order to identify possible preoperative imaging characteristics (including bone scan/99mTc scintigraphy increased endplate uptake, Modic endplate changes, and disc degeneration graded according to Pfirrmann classification) which may be predictive of long-term surgical outcomes .

After controlling for confounders, a combined score, the Lumbar Fusion Outcome Score (LUFOS), was developed. The LUFOS grading system was able to stratify patients in two general groups (Non-surgical: LUFOS 0 and 1; Surgical: LUFOS 2 and 3) that presented significantly different surgical outcomes in terms of estimated marginal means of VAS/back pain (p = 0.001) and ODI (p = 0.006) beginning at 3 months and continuing up to 1 year of follow-up.

In conclusion, LUFOS has been devised as a new practical and surgically oriented grading system based on simple key parameters from non-invasive preoperative imaging exams (magnetic resonance imaging/MRI and bone scan/99mTc scintigraphy) which has been shown to be highly predictive of surgical outcomes of patients undergoing lumbar fusion for treatment for refractory chronic axial LBP.