The Multiple Benefits of Minimally Invasive Spinal Surgery: Results Comparing Transforaminal Lumbar Interbody Fusion and Posterior Lumbar Fusion

Associations of overweight/obesity with patient-reported outcome measures after oblique lumbar interbody fusion

Background

Oblique lateral interbody fusion (OLIF) combined with transpedicular screw fixation has been practiced for degenerative spinal diseases of elderly patients for years. However, overweight patients have been shown to have longer operative times and more complications from surgery. The effect on clinical outcome is still uncertified. The objective of this study was to determine is overweight a risk factor to clinical outcome of OLIF combined with transpedicular screw fixation technique.

Material and methods

A retrospective study in patients submitted to OLIF combined with transpedicular screw fixation from January 2018 to August 2019 was conducted. VAS score, ODI score and EQ5D were measured before the operation and one year after the operation.

Results

A total of 111 patients were included with 48 patients in the non-obese group and 55 patients in the overweight/obese group. There was no significant difference between the two groups in gender, age, smoking history, hypertension, chronic kidney disease and diabetes mellitus. Overweight/obese group has higher BMI (28.4 vs. 22.7, p < 0.001) than non-obese group. There was no difference between the two groups in pre-operative VAS score, ODI score and EQ5D score. However, the healthy weight group improved much more than the overweight score in VAS score, ODI score and EQ5D score.

Conclusion

The overweight/obese patient group had clinical outcomes worse than the non-obese group in terms of pain relief and life functions.

Awake Spinal Fusion Is Associated with Reduced Length of Stay, Opioid Use, and Time to Ambulation Compared to General Anesthesia: A Matched Cohort Study

OBJECTIVE

There is increasing interest in performing awake spinal fusion under spinal anesthesia (SA). Evidence supporting SA has been positive, albeit limited. The authors set out to investigate the effects of SA versus general anesthesia (GA) for spinal fusion procedures on length of stay (LOS), opioid use, time to ambulation (TTA), and procedure duration.

METHODS

The authors performed a retrospective review of a single surgeon's patients who underwent lumbar fusions under SA versus GA from June of 2020 to June of 2022. SA patients were compared to demographically matched GA counterparts undergoing comparable procedures. Analyzed outcomes include operative time, opioid usage in morphine milligram equivalents, TTA, and LOS.

RESULTS

Ten SA patients were matched to 10 GA counterparts. The cohort had a mean age of 66.77, a mean body mass index of 27.73 kg/m2, and a median American Society of Anesthesiologists Physical Status Score of 3.00. LOS was lower in SA versus GA patients (12.87 vs. 50.79 hours, P = 0.001). Opioid utilization was reduced in SA versus GA patients (10.76 vs. 31.43 morphine milligram equivalents, P = 0.006). TTA was reduced in SA versus GA patients (7.22 vs. 29.87 hours, P = 0.022). Procedure duration was not significantly reduced in SA patients compared to GA patients (139.3 vs. 188.2 minutes, P = 0.089).

CONCLUSIONS

These preliminary retrospective results suggest the use of SA rather than GA for lumbar fusions is associated with reduced hospital LOS, reduced opioid utilization, and reduced TTA. Future randomized prospective studies are warranted to determine if SA usage truly leads to these beneficial outcomes.

Factors contributing to the utilization of robotic colorectal surgery: a systematic review and meta-analysis

BACKGROUND

Some studies have suggested disparities in access to robotic colorectal surgery, however, it is unclear which factors are most meaningful in the determination of approach relative to laparoscopic or open surgery. This study aimed to identify the most influential factors contributing to robotic colorectal surgery utilization.

METHODS

We conducted a systematic review and random-effects meta-analysis of published studies that compared the utilization of robotic colorectal surgery versus laparoscopic or open surgery. Eligible studies were identified through PubMed, EMBASE, CINAHL, Cochrane CENTRAL, PsycINFO, and ProQuest Dissertations in September 2021.

RESULTS

Twenty-nine studies were included in the analysis. Patients were less likely to undergo robotic versus laparoscopic surgery if they were female (OR = 0.91, 0.84-0.98), older (OR = 1.61, 1.38-1.88), had Medicare (OR = 0.84, 0.71-0.99), or had comorbidities (OR = 0.83, 0.77-0.91). Non-academic hospitals had lower odds of conducting robotic versus laparoscopic surgery (OR = 0.73, 0.62-0.86). Additional disparities were observed when comparing robotic with open surgery for patients who were Black (OR = 0.78, 0.71-0.86), had lower income (OR = 0.67, 0.62-0.74), had Medicaid (OR = 0.58, 0.43-0.80), or were uninsured (OR = 0.29, 0.21-0.39).

CONCLUSION

When determining who undergoes robotic surgery, consideration of factors such as age and comorbid conditions may be clinically justified, while other factors seem less justifiable. Black patients and the underinsured were less likely to undergo robotic surgery. This study identifies nonclinical disparities in access to robotics that should be addressed to provide more equitable access to innovations in colorectal surgery.

Clinical Effect of Minimally Invasive Microendoscopic-Assisted Transforaminal Lumbar Interbody Fusion for Single-Level Lumbar Disc Herniation

OBJECTIVE

This retrospective study aimed to compare the clinical and radiological outcomes of transforaminal lumbar interbody fusion (TLIF) through the Wiltse approach (W-TLIF) vs minimally invasive microendoscopy-assisted transforaminal lumbar interbody fusion (ME-TLIF) in single-segment lumbar disc herniation (LDH).

METHODS

A retrospective study was conducted to study the differences in specific clinical outcomes between single-segment LDH patients receiving W-TLIF and ME-TLIF. Single-segment LDH patients admitted to the Fujian Medical University Union Hospital from March 2015 to June 2018 were included. All the participants were divided into the ME-TLIF group or the W-TLIF group according to their TLIF surgery types. Demographic characteristics, the visual analog score (VAS), Oswestry Disability Index (ODI), Japanese Orthopaedic Association (JOA) scale, blood loss volume, postoperative drainage, ambulated time, initial postoperative back pain, hospitalization duration, expenses, and improvement rates of patients in the two groups were collected for analysis. Radiographic fusion was ultimately assessed via the Bridwell interbody fusion grading system. All selected patients with TLIF were followed up for 1 year.

RESULTS

Fifty-seven patients were selected, with 26 in the ME-TLIF group and 31 in the W-TLIF group, both of whom were followed up for 1 year. The mean age of the included patients was 53.75 ± 9.313 years, and the sex ratio was indiscrimination. There was no significant difference in demographic data or operating time between the two groups prior to surgery. The blood loss volume (ME-TLIF: 228.5 vs W-TLIF: 681.3), postoperative drainage (ME-TLIF:82.1 ± 23.5 vs W-TLIF: 345.8 ± 65.2), initial postoperative back pain (ME-TLIF: VAS_3 days: 1.96 ± 0.60 VAS_7 days: 1.73 ± 0.53, W-TLIF: VAS_3 days: 2.48 ± 0.51 VAS_7 days: 1.87 ± 0.43), and hospitalization duration (ME-TLIF: 9.04 vs. W-TLIF: 11.29) were all significantly lower in the ME-TILF group (p < 0.05). However, there were no statistical differences between the two groups in VAS, ODI, and JOA at 1 month, 3 months, 6 months, and 1 year postoperatively (p > 0.05). The fusion rates of the two groups showed no notable difference (p > 0.05), while the X-ray exposure time in the ME-TLIF group was significantly longer than in the W-TLIF group (p < 0.05).

CONCLUSIONS

ME-TLIF surgery was an effective and satisfactory surgical technique to manage LDH. Although ME-TLIF increased the operation time and intraoperative fluoroscopic irradiation volume, it could effectively relieve low back pain from early postoperative onset and promote early postoperative recovery compared with W-TLIF.

Minimally invasive versus open transforaminal lumbar interbody fusion: a prospective, controlled observational study of short-term outcome

Instrumented stabilization with intersomatic fusion can be achieved by open (O-TLIF) or minimally invasive (MIS-TLIF) transforaminal surgical access. While less invasive techniques have been associated with reduced postoperative pain and disability, increased manipulation and insufficient decompression may contradict MIS techniques. In order to detect differences between both techniques in the short-term, a prospective, controlled study was conducted. Thirty-eight patients with isthmic or degenerative spondylolisthesis or degenerative disk disease were included in this prospective, controlled study (15 MIS-TLIF group vs. 23 O-TLIF group) after failed conservative treatment. Patients were examined preoperatively, on the first, third, and sixth postoperative day as well as after 2, 4, and 12 weeks postoperatively. Outcome parameters included blood loss, duration of surgery, pre- and postoperative pain (numeric rating scale [NRS], visual analog scale [VAS]), functionality (Timed Up and Go test [TUG]), disability (Oswestry Disability index [ODI]), and quality of life (EQ-5D). Intraoperative blood loss (IBL) as well as postoperative blood loss (PBL) was significantly higher in the O-TLIF group ([IBL O-TLIF 528 ml vs. MIS-TLIF 213 ml, p = 0.001], [PBL O-TLIF 322 ml vs. MIS-TLIF 30 ml, p = 0.004]). The O-TLIF cohort showed significantly less leg pain postoperatively compared to the MIS-TLIF group ([NRS leg 3rd postoperative day, p = 0.027], [VAS leg 12 weeks post-op, p = 0.02]). The MIS group showed a significantly better improvement in the overall ODI (40.8 ± 13 vs. 56.0 ± 16; p = 0.05). After 3 months in the short-term follow-up, the MIS procedure tends to have better results in terms of patient-reported quality of life. MIS-TLIF offers perioperative advantages but may carry the risk of increased nerve root manipulation with consecutive higher radicular pain, which may be related to the learning curve of the procedure.

Development and Initial Internal Validation of a Novel Classification System for Perioperative Expectations Following Minimally Invasive Degenerative Lumbar Spine Surgery

STUDY DESIGN

This was a prospective consecutive clinical cohort study.

OBJECTIVE

The purpose of our study was to develop and provide an initial internal validation of a novel classification system that can help surgeons and patients better understand their postoperative course following the particular minimally invasive surgery (MIS) and approach that is utilized.

SUMMARY OF BACKGROUND DATA

Surgeons and patients are often attracted to the option of minimally invasive spine surgery because of the perceived improvement in recovery time and postsurgical pain. A classification system based on the impact of the surgery and surgical approach(es) on postoperative recovery can be particularly helpful.

METHODS

Six hundred thirty-one patients who underwent MIS lumbar/thoracolumbar surgery for degenerative conditions of the spine were included. Perioperative outcomes-operative time, estimated blood loss, postsurgical length of stay (LOS), 90-day complications, postoperative day zero narcotic requirement [in Morphine Milligram Equivalent (MME)], and need for intravenous patient-controlled analgesia (IV PCA).

RESULTS

Postoperative LOS and postoperative narcotic use were deemed most clinically relevant, thus selected as primary outcomes. Type of surgery was significantly associated with all outcomes (P<0.0001), except intraoperative complications. Number of levels for fusion was significantly associated with operative time, in-hospital complications, 24 hours oral MME, and the need for IV PCA and LOS (P<0.0001). Number of surgical approaches for lumbar fusion was significantly associated with operative time, 24 hours oral MME, need for IV PCA and LOS (P<0.001). Based on these parameters, the following classification system ("Qureshi-Louie classification" for MIS degenerative lumbar surgery) was devised: (1) Decompression-only; (2) Fusion-1 and 2 levels, 1 approach; (3) Fusion-1 level, 2 approaches; (4) Fusion-2 levels, 2 approaches; (5) Fusion-3+ levels, 2 approaches.

CONCLUSIONS

We present a novel classification system and initial internal validation to describe the perioperative expectations following various MIS surgeries in the degenerative lumbar spine. This initial description serves as the basis for ongoing external validation.

Awake minimally invasive transforaminal lumbar interbody fusion with a pedicle-based retraction system

OBJECTIVE

Recently there has been increasing interest in the use of regional anesthesia for minimally-invasive transforaminal lumbar interbody fusion (TLIF) and laminectomy, with the goal of reducing the side effects and risks associated with general anesthesia and also to improve patient satisfaction. The goal of this technical note is to describe important perioperative aspects to safely perform an awake spine surgery and to describe a novel technique to preform minimally-invasive TLIF using a pedicle-based retraction system.

METHODS

We report our patient selection criteria, perioperative anesthesia protocol and surgical technique for awake TLIF with the Maximum Access Surgery (MAS) TLIF Retraction System. We describe an illustrative case of a 66-year-old female that presented with leg pain, lumbar MRI revealed a grade one spondylolisthesis at L4-5 with severe canal stenosis. She underwent a L4-5 Awake MIS TLIF using the MAS TLIF Retraction System.

RESULTS

The first 10 awake TLIF we performed with the MAS TLIF Retraction System had a mean procedure time of 117.3 min with a standard deviation (SD) of 13, and a mean total OR time of 151 min, SD 14.5. No surgery was converted under general anesthesia. No intraoperative complications were reported. Average length of stay was 1.3 ± 0.46 days.

CONCLUSION

Awake MAS TLIF is a safe and effective technique, with the advantage of reducing the risk and side effect of general anesthesia and the approach-associated damage to soft tissues and morbidity. The pedicle-based distraction allows easier access to the intervertebral disc space for both disc preparation and cage placement.

Postoperative decrease of regional volumetric bone mineral density measured by quantitative computed tomography after lumbar fusion surgery in adjacent vertebrae

We investigated the effect of posterior lumbar fusion surgery on the regional volumetric bone mineral density (vBMD) measured by quantitative computed tomography. Surgery negatively affected the regional vBMD in adjacent levels. Interbody fusion was independently associated with vBMD decline and preoperative epidural steroid injections (ESIs) were associated with less postoperative vBMD decline.

INTRODUCTION

Few studies investigate postoperative BMD changes after lumbar fusion surgery utilizing quantitative computed tomography (QCT). Additionally, it remains unclear what preoperative and operative factors contribute to postoperative BMD changes. The purpose of this study is to investigate the effect of lumbar fusion surgery on regional volumetric bone mineral density (vBMD) in adjacent vertebrae and to identify potential modifiers for postoperative BMD change.

METHODS

The data of patients undergoing posterior lumbar fusion with available pre- and postoperative CTs were reviewed. The postoperative changes in vBMD in the vertebrae one or two levels above the upper instrumented vertebra (UIV+1, UIV+2) and one level below the lower instrumented vertebra (LIV+1) were analyzed. As potential contributing factors, history of ESI, and the presence of interbody fusion, as well as various demographic/surgical factors, were included.

RESULTS

A total of 90 patients were included in the study analysis. Mean age (±SD) was 62.1 ± 11.7. Volumetric BMD (±SD) in UIV+1 was 115.4 ± 36.9 mg/cm³ preoperatively. The percent vBMD change in UIV+1 was - 10.5 ± 12.9% (p < 0.001). UIV+2 and LIV+1 vBMD changes showed similar trends. After adjusting with the interval between surgery and the secondary CT, non-Caucasian race, ESI, and interbody fusion were independent contributors to postoperative BMD change in UIV+1.

CONCLUSIONS

Posterior lumbar fusion surgery negatively affected the regional vBMDs in adjacent levels. Interbody fusion was independently associated with vBMD decline. Preoperative ESIs were associated with less postoperative vBMD decline, which was most likely a result of a preoperative decrease in vBMD due to ESIs.

Postoperative Anemia Predicts Length of Stay for Geriatric Patients Undergoing Minimally Invasive Lumbar Spine Fusion Surgery

Introduction:

We hypothesize that postoperative anemia will predict length of stay (LOS) for geriatric patients undergoing minimally invasive (MIS) lumbar spine fusions.

Materials and Methods:

Patients who underwent MIS lateral and transforaminal lumbar interbody fusion between January 2017 and March 2018 at an academic tertiary care referral center were selected. Eighty-one patients were included. The primary outcome variable was LOS, measured in days. The predictors studied were preoperative hemoglobin (Hgb), postoperative day 1 Hgb, postoperative nadir Hgb, intraoperative Hgb decrement (preoperative Hgb-postoperative day 1 Hgb), perioperative Hgb decrement (preoperative Hgb-postoperative nadir Hgb), age, American Society of Anesthesiologists–Physical Status (ASA-PS) score, volume of perioperative intravenous (IV) fluids (IVFs), and number of levels fused. Simple linear regression and analysis of variance were used for statistical analysis.

Results:

In the present study, preoperative anemia was not associated with longer LOS (P = .15). Postoperative anemia was associated with longer LOS as both postoperative day 1 Hgb (P = .05*) and postoperative nadir Hgb (P < .0001*) predicted longer LOS. Greater intraoperative Hgb decrement did not predict longer LOS (P = .36); however, greater perioperative Hgb decrement predicted longer LOS (P < .0001*). Older age (P = .01*) and greater number of levels fused (P = .03*) predicted longer LOS; however, a greater ASA-PS classification did not predict longer LOS. Greater IVF administration was associated with longer LOS (P < .0001*).

Discussion:

Postoperative nadir Hgb (P < .0001*) was more predictive of longer LOS than postoperative day 1 Hgb (P = .05*). There is a perioperative Hgb decrement associated with longer LOS (P < .0001*). Geriatric patients may be more susceptible to the potential contributors to Hgb decrement, including occult bleeding post-op and hemodilution from IVF administration.

Conclusion:

Postoperative anemia, perioperative decrement in Hgb, older age, greater number of levels fused, and greater total IVFs administered predict longer LOS. Understanding the impact of these factors on LOS is critical as these procedures increasingly move to the outpatient setting.

The Prevalence of the Use of MIS Techniques in the Treatment of Adult Spinal Deformity (ASD) Amongst Members of the Scoliosis Research Society (SRS) in 2016

STUDY DESIGN

Electronic survey administered to Scoliosis Research Society members.

OBJECTIVE

To determine the prevalence of minimally invasive surgery (MIS) techniques for the treatment of adult spinal deformity.

SUMMARY OF BACKGROUND DATA

There is a paucity of data available on the practice pattern, prevalence of minimally invasive spine surgery, and the preferred minimally invasive techniques in the treatment of adult spine deformity.

METHODS

An electronic nine-question survey regarding individual usage pattern of minimally invasive spine surgery techniques was administered in 2016 to the members of the Scoliosis Research Society. Determinants included complexity in condition of patient population, prevalence of use of minimally invasive techniques in the surgeon's practice, prevalence of use of a particular MIS technique, strategy elected during surgery, adoption of staging of procedures and timing between staging of procedures.

RESULTS

A total of 357 surgeons responded (61.3% response rate), and 154 (43.1%) of the respondents said that they use MIS as a part of their surgical treatment of adult spinal deformity. However, of these 154 respondents, 67 (43.5%) said that their MIS usage in deformity practice was between 1% and 20%. Only 11 (7.2%) said that they used MIS 81% to 100% of the time. The top MIS approaches that surgeons chose were MIS lateral lumbar interbody fusion 109 (70.59%) and MIS percutaneous screws 91 (58.8%).

CONCLUSIONS

The low rate of adoption of these techniques among the SRS members may be due to the false perception that there is not enough data to support that MIS techniques are better. This and the fact that a practitioner needs to be facile at different MIS techniques may be the true impediment to the adoption of MIS techniques in the treatment of ASD.

LEVEL OF EVIDENCE

Level IV.

The Utility of Routinely Obtaining Postoperative Laboratory Studies Following a Minimally Invasive Transforaminal Lumbar Interbody Fusion

STUDY DESIGN

This is a retrospective analysis.

OBJECTIVE

To test the hypothesis that there is limited utility in routinely obtaining postoperative laboratory values following minimally invasive transforaminal lumbar interbody fusion (MIS TLIF).

BACKGROUND DATA

At many institutions, it is routine to obtain a complete blood count and basic metabolic profile (BMP) following a MIS TLIF. However, the utility of this practice has not been well characterized.

METHODS

A total of 332 consecutive patients who underwent a primary, 1-level MIS TLIF for degenerative spinal pathology between 2007 and 2013 were identified. Patients were stratified into low-risk and high-risk cohorts based upon risk for postoperative laboratory abnormalities. Inclusion criteria for the high-risk cohort were malignancy, complicated diabetes, renal failure, liver disease, hematologic disease, or significant intraoperative blood loss (>300 mL). Preoperative and postoperative hemoglobin (Hb), hematocrit, and BMP values were compared. Any interventions that were potentially related to laboratory values were identified.

RESULTS

Totals of 270 low-risk and 62 high-risk patients were identified. Mean postoperative Hb, hematocrit, blood urea nitrogen, sodium, potassium, and calcium values were decreased compared with preoperative values (P<0.001 for each) in both cohorts. Similar changes from preoperative levels were demonstrated in each cohort. No patients received blood product transfusion. Eleven low-risk (4.1%) and 5 high-risk patients (8.1%) received oral potassium supplementation. All patients who received potassium supplementation were asymptomatic. Most patients who were given potassium replacement consumed medications known to decrease serum potassium levels. No other interventions were performed in either group.

CONCLUSIONS

Despite a significant decrease in mean Hb concentration following surgery, no patients required a transfusion. In total, 16 patients received potassium supplementation likely related to medication-related potassium deficits. Overall, these findings suggest that the utility of routinely obtaining a complete blood count or BMP following uncomplicated MIS TLIF may be limited except in the setting of select preoperative comorbidities and/or perioperative risk factors or events.

LEVEL OF EVIDENCE

Level III.

How are patients influenced when counseled for minimally invasive lumbar spine surgeries? A stepwise model assessing pivotal information for decision-making

BACKGROUND CONTEXT

Although minimally invasive surgery (MIS)-transforaminal lumbar interbody fusion (TLIF) has many evidence-based short-term benefits over open TLIF, both procedures have similar long-term outcomes. Patients' preference for MIS over open TLIF may be confounded by a lack of understanding of what each approach entails.

PURPOSE

The study aimed to identify the various factors influencing patients' choice between MIS and open TLIF.

STUDY DESIGN/SETTING

This is a cross-sectional study conducted at a tertiary health-care institution.

PATIENT SAMPLE

Patients, for whom TLIF procedures were indicated, were recruited over a 3-month period from specialist outpatient clinics.

OUTCOME MEASURE

The outcome measure was patients' choice of surgical approach (MIS or open).

METHODS

All patients were subjected to a stepwise interviewing process and were asked to select between open and MIS approaches at each step. Further subgroup analysis stratifying subjects based on stages of decision-making was performed to identify key predictors of selection changes. No sources of funding were required for this study and there are no conflicts of interests.

RESULTS

Fifty-four patients with a mean age of 55.8 years participated in the study. Thirteen (24.1%) consistently selected a single approach, whereas 31 (57.4%) changed their selection more than once during the interviewing process. Overall, 12 patients (22.2%) had a final decision different from their initial choice, and 15 patients (27.8%) were unable to decide. A large proportion of patients (65.0%) initially favored the open approach's midline incision. This proportion dropped to 16.7% (p<.001) upon mention of the term MIS. The proportion of patients favoring MIS dropped significantly following discussion on the pros and cons (p=.002) of each approach, as well as conversion or revision surgery (p=.017). Radiation and cosmesis were identified as the two most important factors influencing patients' final decisions.

CONCLUSIONS

The longer midline incision of the open approach is cosmetically more appealing to patients than the paramedian stab wounds of MIS. The advantages of the MIS approach may not be as valued by patients as they are by surgeons. Given the equivalent long-term outcomes of both approaches, it is crucial that patients are adequately informed during preoperative counseling to achieve the best consensus decision.

Is the use of minimally invasive fusion technologies associated with improved outcomes after elective interbody lumbar fusion? Analysis of a nationwide prospective patient-reported outcomes registry

BACKGROUND CONTEXT

Over the last decade, clinical investigators and biomedical industry groups have used significant resources to develop advanced technologies that enable less invasive spine fusions. These minimally invasive surgery (MIS) technologies often require increased expenditures by hospitals and payers. Although several small single center studies have suggested MIS technologies decrease surgical morbidity and reduce hospital stay, evidence documenting benefit from a patient perspective remains limited. Furthermore, MIS outcomes have yet to be evaluated from the perspective of multiple practice types representing the broad spectrum of US spine surgery.

PURPOSE

This study aimed to examine a population of patients who underwent one- or two-level interbody lumbar fusion diagnosed with lumbar stenosis or Grade 1 spondylolisthesis in an observational, prospective national registry for the purposes of determining how MIS and traditional open technologies affect postsurgical and patient-reported outcomes (PROs).

STUDY DESIGN/SETTING

This study used observational analysis of prospectively collected data.

PATIENT SAMPLE

The sample consisted of cases from the National Neurosurgery Quality and Outcomes Database (N²QOD).

OUTCOME MEASURES

Numeric rating scale for back and leg pain, Oswestry Disability Index, EuroQol-5D, return to work, and perioperative morbidity were the outcome measures.

METHODS

The N²QOD is a prospective PROs registry enrolling patients undergoing elective spine surgery from 60 hospitals in 27 US states via representative sampling. We analyzed the N²QOD aggregate dataset (2010-2014) to identify one- and two-level lumbar interbody fusion procedures performed for lumbar stenosis or Grade 1 spondylolisthesis with 12 months' follow-up where surgical instrumentation and implant types were clearly identified. Perioperative and 1-year outcomes were compared between cases performed with MIS enabling technologies versus traditional open technologies before and after propensity matching.

RESULTS

There were 467 (24%) patients who underwent elective interbody lumbar fusion using MIS enabling technologies whereas 1,480 (76%) underwent the procedure using traditional open technologies. The MIS patients were slightly healthier (American Society of Anesthesiologists grade), had private insurance more frequently, and underwent two-level fusion less frequently. Unmatched, the MIS cohort was associated with reduced blood loss, a 0.7-day reduction in mean length of hospital stay, and 5% reduced need for post-discharge inpatient rehabilitation, but equivalent 90-day safety measures. After propensity matching, the MIS cohort remained associated with reduced blood loss and a shorter length of stay for one-level fusion (p<.05) but had equivalent length of stay for two-level fusion. Outcomes in all other 90-day safety measures were similar. In both unadjusted and propensity-matched comparison, MIS versus open technologies were associated with equivalent return to work, patient-reported pain, physical disability, and quality of life at 3 and 12 months' follow-up.

CONCLUSIONS

In a representative sampling registry of elective interbody lumbar spine fusion procedures spanning 27 US states, nearly a quarter of procedures performed from 2010 to 2014 used minimally invasive enabling technologies. Regardless of approach, interbody lumbar fusion was associated with significant and sustained improvements in all measured health domains. When used in everyday care by a wide spectrum of spine surgeons in non-research settings, the use of MIS technologies was associated with reduced intraoperative blood loss but only a half-day reduction in mean length of hospital stay for one-level fusions. Minimally invasive surgery was not associated with any improved perioperative safety measures or 12-month outcomes. Although MIS enabling technologies may increase some in-hospital care efficiencies, MIS clinical outcomes are similar to open surgery for patients undergoing one- and two-level interbody lumbar fusions.

Comparison of complication rates of minimally invasive transforaminal lumbar interbody fusion and lateral lumbar interbody fusion: a systematic review of the literature

OBJECT Minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) and lateral lumbar interbody fusion (LLIF) are 2 currently popular techniques for lumbar arthrodesis. The authors compare the total risk of each procedure, along with other important complication outcomes. METHODS This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Relevant studies (up to May 2015) that reported complications of either MI-TLIF or LLIF were identified from a search in the PubMed database. The primary outcome was overall risk of complication per patient. Secondary outcomes included risks of sensory deficits, temporary neurological deficit, permanent neurological deficit, intraoperative complications, medical complications, wound complications, hardware failure, subsidence, and reoperation. RESULTS Fifty-four studies were included for analysis of MI-TLIF, and 42 studies were included for analysis of LLIF. Overall, there were 9714 patients (5454 in the MI-TLIF group and 4260 in the LLIF group) with 13,230 levels fused (6040 in the MI-TLIF group and 7190 in the LLIF group). A total of 1045 complications in the MI-TLIF group and 1339 complications in the LLIF group were reported. The total complication rate per patient was 19.2% in the MI-TLIF group and 31.4% in the LLIF group (p < 0.0001). The rate of sensory deficits and temporary neurological deficits, and permanent neurological deficits was 20.16%, 2.22%, and 1.01% for MI-TLIF versus 27.08%, 9.40%, and 2.46% for LLIF, respectively (p < 0.0001, p < 0.0001, p = 0.002, respectively). Rates of intraoperative and wound complications were 3.57% and 1.63% for MI-TLIF compared with 1.93% and 0.80% for LLIF, respectively (p = 0.0003 and p = 0.034, respectively). No significant differences were noted for medical complications or reoperation. CONCLUSIONS While there was a higher overall complication rate with LLIF, MI-TLIF and LLIF both have acceptable complication profiles. LLIF had higher rates of sensory as well as temporary and permanent neurological symptoms, although rates of intraoperative and wound complications were less than MI-TLIF. Larger, prospective comparative studies are needed to confirm these findings as the current literature is of relative poor quality.

Perioperative outcomes and adverse events of minimally invasive versus open posterior lumbar fusion: meta-analysis and systematic review

OBJECT

The objective of this study was to determine the clinical comparative effectiveness and adverse event rates of posterior minimally invasive surgery (MIS) compared with open transforaminal or posterior lumbar interbody fusion (TLIF/PLIF).

METHODS

A systematic review of the Medline, EMBASE, PubMed, Web of Science, and Cochrane databases was performed. A hand search of reference lists was conducted. Studies were reviewed by 2 independent assessors to identify randomized controlled trials (RCTs) or comparative cohort studies including at least 10 patients undergoing MIS or open TLIF/PLIF for degenerative lumbar spinal disorders and reporting at least 1 of the following: clinical outcome measure, perioperative clinical or process measure, radiographic outcome, or adverse events. Study quality was assessed using the Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) protocol. When appropriate, a meta-analysis of outcomes data was conducted.

RESULTS

The systematic review and reference list search identified 3301 articles, with 26 meeting study inclusion criteria. All studies, including 1 RCT, were of low or very low quality. No significant difference regarding age, sex, surgical levels, or diagnosis was identified between the 2 cohorts (856 patients in the MIS cohort, 806 patients in the open cohort). The meta-analysis revealed changes in the perioperative outcomes of mean estimated blood loss, time to ambulation, and length of stay favoring an MIS approach by 260 ml (p < 0.00001), 3.5 days (p = 0.0006), and 2.9 days (p < 0.00001), respectively. Operative time was not significantly different between the surgical techniques (p = 0.78). There was no significant difference in surgical adverse events (p = 0.97), but MIS cases were significantly less likely to experience medical adverse events (risk ratio [MIS vs open] = 0.39, 95% confidence interval 0.23-0.69, p = 0.001). No difference in nonunion (p = 0.97) or reoperation rates (p = 0.97) was observed. Mean Oswestry Disability Index scores were slightly better in the patients undergoing MIS (n = 346) versus open TLIF/PLIF (n = 346) at a median follow-up time of 24 months (mean difference [MIS - open] = 3.32, p = 0.001).

CONCLUSIONS

The result of this quantitative systematic review of clinical comparative effectiveness research examining MIS versus open TLIF/PLIF for degenerative lumbar pathology suggests equipoise in patient-reported clinical outcomes. Furthermore, a meta-analysis of adverse event data suggests equivalent rates of surgical complications with lower rates of medical complications in patients undergoing minimally invasive TLIF/PLIF compared with open surgery. The quality of the current comparative evidence is low to very low, with significant inherent bias.

Lateral lumbar interbody fusion for sagittal balance correction and spinal deformity

We conducted a systematic review to assess the safety and clinical and radiological outcomes of the recently introduced, direct or extreme lateral lumbar interbody fusion (XLIF) approach for degenerative spinal deformity disorders. Open fusion and instrumentation has traditionally been the mainstay treatment. However, in recent years, there has been an increasing emphasis on minimally invasive fusion and instrumentation techniques, with the aim of minimizing surgical trauma and blood loss and reducing hospitalization. From six electronic databases, 21 eligible studies were included for review. The pooled weighted average mean of preoperative visual analogue scale (VAS) pain scores was 6.8, compared to a postoperative VAS score of 2.9 (p<0.0001). The weighted average preoperative and postoperative coronal segmental Cobb angles were 3.6 and 1.1°, respectively. The weighted average preoperative and postoperative coronal regional Cobb angles were 19.1 and 10.0°, respectively. Regional lumbar lordosis also significantly improved from 35.8 to 43.3°. Sagittal alignment was comparable pre- and postoperatively (34 mm versus 35.1mm). The weighted average operative duration was 125.6 minutes, whilst the mean estimated blood loss was 155 mL. The weighted average hospitalization length was 3.6 days. Whilst the available data is limited, minimally invasive XLIF procedures appear to be a promising alternative for the treatment of scoliosis, with improved functional VAS and Oswestry disability index outcomes and restored coronal deformity. Future comparative studies are warranted to assess the long term benefits and risks of XLIF compared to anterior and posterior procedures.

Minimally invasive percutaneous screw fixation of traumatic spondylolisthesis of the axis

OBJECT

Most cases of traumatic spondylolisthesis of the axis (hangman's fracture) can be treated nonoperatively with reduction and subsequent immobilization in a rigid cervical collar or halo. However, in some instances, operative management is necessary and can be accomplished by using either anterior or posterior fusion techniques. Because open posterior procedures can result in significant blood loss, pain, and limited cervical range of motion, other less invasive options for posterior fixation are needed. The authors describe a minimally invasive, navigation-guided technique for surgical treatment of Levine-Edwards (L-E) Type II hangman's fractures.

METHODS

For 5 patients with L-E Type II hangman's fracture requiring operative reduction and internal fixation, percutaneous screw fixation directed through the fracture site was performed. This technique was facilitated by use of intraoperative 3D fluoroscopy and neuronavigation.

RESULTS

Of the 5 patients, 2 were women, 3 were men, and age range was 46–67 years. No intraoperative or postoperative complications occurred. All patients wore a rigid cervical collar, and flexion-extension radiographs were obtained at 6 months. For all patients, dynamic imaging demonstrated a stable construct.

CONCLUSIONS

L-E type II hangman's fractures can be safely repaired by using percutaneous minimally invasive surgical techniques. This technique may be appropriate, depending on circumstances, for all L-E Type I and II hangman's fractures; however, the degree of associated ligament injury and disc disruption must be accounted for. Percutaneous fixation is not appropriate for L-E Type III fractures because of significant displacement and ligament and disc disruption. This report is meant to serve as a feasibility study and is not meant to show superiority of this procedure over other surgical options.

Is Minimally Invasive Spine Surgery Also Minimally Pro-Inflammatory? Muscular Markers, Inflammatory Parameters and Cytokines to Quantify the Operative Invasiveness Assessment in Spine Fusion

Over the last decades, minimally invasive surgery (MIS) techniques entered in the surgical routine due to their major advantage in reducing the unnecessary exposure of tissue and, thus, the trauma. Even in the context of orthopedics and spine surgery these practices have been widely developed and applied. Besides the clinical outcome of the patients, few studies have quantitatively assessed the traumatic and inflammatory effects of a specific surgical technique. Indeed, currently, a universally accepted biological outcome measure, such as a panel of biochemical markers, to define the success of MIS approach is still lacking. We reviewed the literature to collect the published data regarding the quantitative analysis of trauma induced by either conventional or minimally invasive surgery with the aim of highlighting evidence useful to guide future studies. Previous publications show some evidence in support of the hypothesis that MIS approaches are less traumatic, and possibly less pro-inflammatory, than conventional ones. Creatin kinase (as a marker of muscular damage) and C-reactive protein (as a marker of systemic inflammation) seem to reproducibly follow different trends in minimally invasive surgery compared to conventional procedures. Moreover, cytokines, such as interleukin (IL)-6 and IL-10 are also promising markers in this context.

Minimally invasive versus open transforaminal lumbar interbody fusion for degenerative spondylolisthesis: comparative effectiveness and cost-utility analysis

BACKGROUND

Minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) for lumbar spondylolisthesis allows for the surgical treatment of back/leg pain while minimizing tissue injury and accelerating the patient's recovery. Although previous results have shown shorter hospital stays and decreased intraoperative blood loss for MIS versus open TLIF, short- and long-term outcomes have been similar. Therefore, we performed comparative effectiveness and cost-utility analysis for MIS versus open TLIF.

METHODS

A total of 100 patients (50 MIS, 50 open) undergoing TLIF for lumbar spondylolisthesis were prospectively studied. Back-related medical resource use, missed work, and quality-adjusted life years were assessed. Cost of in-patient care, direct cost (2-year resource use × unit costs based on Medicare national allowable payment amounts), and indirect cost (work-day losses × self-reported gross-of-tax wage rate) were recorded, and the incremental cost-effectiveness ratio was calculated.

RESULTS

Length of hospitalization and time to return to work were less for MIS versus open TLIF (P = 0.006 and P = 0.03, respectively). MIS versus open TLIF demonstrated similar improvement in patient-reported outcomes assessed. MIS versus open TLIF was associated with a reduction in mean hospital cost of $1758, indirect cost of $8474, and total 2-year societal cost of $9295 (P = 0.03) but similar 2-year direct health care cost and quality-adjusted life years gained.

CONCLUSIONS

MIS TLIF resulted in reduced operative blood loss, hospital stay and 2-year cost, and accelerated return to work. Surgical morbidity, hospital readmission, and short- and long-term clinical effectiveness were similar between MIS and open TLIF. MIS TLIF may represent a valuable and cost-saving advancement from a societal and hospital perspective.

Cost-utility analysis of posterior minimally invasive fusion compared with conventional open fusion for lumbar spondylolisthesis

Background

The utility and cost of minimally invasive surgical (MIS) fusion remain controversial. The primary objective of this study was to compare the direct economic impact of 1- and 2-level fusion for grade I or II degenerative or isthmic spondylolisthesis via an MIS technique compared with conventional open posterior decompression and fusion.

Methods

A retrospective cohort study was performed by use of prospective data from 78 consecutive patients (37 with MIS technique by 1 surgeon and 41 with open technique by 3 surgeons). Independent review of demographic, intraoperative, and acute postoperative data was performed. Oswestry disability index (ODI) and Short Form 36 (SF-36) values were prospectively collected preoperatively and at 1 year postoperatively. Cost-utility analysis was performed by use of in-hospital micro-costing data (operating room, nursing, imaging, laboratories, pharmacy, and allied health cost) and change in health utility index (SF-6D) at 1 year.

Results

The groups were comparable in terms of age, sex, preoperative hemoglobin, comorbidities, and body mass index. Groups significantly differed (P < .01) regarding baseline ODI and SF-6D scores, as well as number of 2-level fusions (MIS, 12; open, 20) and number of interbody cages (MIS, 45; open, 14). Blood loss (200 mL vs 798 mL), transfusions (0% vs 17%), and length of stay (LOS) (6.1 days vs 8.4 days) were significantly (P < .01) lower in the MIS group. Complications were also fewer in the MIS group (4 vs 12, P < .02). The mean cost of an open fusion was 1.28 times greater than that of an MIS fusion (P = .001). Both groups had significant improvement in 1-year outcome. The changes in ODI and SF-6D scores were not statistically different between groups. Multivariate regression analysis showed that LOS and number of levels fused were independent predictors of cost. Age and MIS were the only predictors of LOS. Baseline outcomes and MIS were predictors of 1-year outcome.

Conclusion

MIS posterior fusion for spondylolisthesis does reduce blood loss, transfusion requirements, and LOS. Both techniques provided substantial clinical improvements at 1 year. The cost utility of the MIS technique was considered comparable to that of the open technique.

Level of Evidence

Level III.

[Minimally invasive spine arthrodesis in degenerative spinal disorders]

BACKGROUND AND PURPOSE

As in many other surgical fields, new minimally invasive techniques have been developed over the past 20 years, with reducing the muscular trauma associated with the traditional surgical approach and reducing related morbidity as the main goals. Initially limited to the laparoscopic or video-assisted approaches of the anterior spine, these techniques have been extended to the posterior transmuscular access of the lumbar spine. This article reviews the value of these approaches in the treatment of degenerative lumbar spine disorders.

METHODS

We describe the main techniques used in minimally invasive lumbar spine surgery, including posterior pedicle screwing as well as anterior (ALIF), posterior (PLIF), transforaminal (TLIF), extreme lateral (XLIf), and presacral (AxiaLIF) interbody fusion. The results of recently published series are reported.

RESULTS

Percutaneous pedicle screwing is reported to be an effective technique of lumbar spine arthrodesis associated with a low rate of screw misplacement. Minimally invasive PLIF, TLIF, and ALIF have been associated with shorter mean operative time, less postoperative pain, reduction of the estimated blood loss, a shorter hospital stay, and quicker functional recovery. Despite these encouraging early clinical results, no prospective, randomized published scientific study has proved that minimally invasive techniques are better than standard techniques. Larger clinical series with a longer follow-up could fill this gap.

The quantitative analysis of back muscle degeneration after posterior lumbar fusion: comparison of minimally invasive and conventional open surgery

STUDY DESIGN

Prospective controlled study.

PURPOSE

The results of conventional open surgery was compared with those from minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) for lumbar fusion to determine which approach resulted in less postoperative paraspinal muscle degeneration.

OVERVIEW OF LITERATURE

MI TLIF is new surgical technique that appears to minimize iatrogenic injury. However, there aren't any reports yet that have quantitatively analyzed and proved whether there's difference in back muscle injury and degeneration between the minimally invasive surgery and conventional open surgery in more than 1 year follow-up after surgery.

METHODS

This study examined a consecutive series of 48 patients who underwent lumbar fusion in our hospital during the period, March 2006 to March 2008, with a 1-year follow-up evaluation using MRI. There were 17 cases of conventional open surgery and 31 cases of MI-TLIF (31 cases of single segment fusion and 17 cases of multi-segment fusion). The digital images of the paravertebral back muscles were analyzed and compared using the T2-weighted axial images. The point of interest was the paraspinal muscle of the intervertebral disc level from L1 to L5. Picture archiving and communication system viewing software was used for quantitative analysis of the change in fat infiltration percentage and the change in cross-sectional area of the paraspinal muscle, before and after surgery.

RESULTS

A comparison of the traditional posterior fusion method with MI-TLIF revealed single segment fusion to result in an average increase in fat infiltration in the paraspinal muscle of 4.30% and 1.37% and a decrease in cross-sectional area of 0.10 and 0.07 before and after surgery, respectively. Multi-segment fusion showed an average 7.90% and 2.79% increase in fat infiltration and a 0.16 and 0.10 decrease in cross-sectional area, respectively. Both single and multi segment fusion showed less change in the fat infiltration percentage and cross-sectional area, particularly in multi segment fusion. There was no significant difference between the two groups in terms of the radiologic results.

CONCLUSIONS

A comparison of conventional open surgery with MI-TLIF upon degeneration of the paraspinal muscle with a 1 year follow-up evaluation revealed that both single and multi segment fusion showed less change in fat infiltration percentage and cross-sectional area in the MI-TLIF but there was no significant difference between the two groups. This suggests that as time passes after surgery, there is no significant difference in the level of degeneration of the paraspinal muscle between surgical techniques.