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lateral_lumbar_interbody_fusion

Lateral lumbar interbody fusion (LLIF)

Lateral lumbar interbody fusion (LLIF) is a minimally invasive technique first described by Ozgur et al. 1). LLIF allows the surgeon to access the intervertebral space via a minimally invasive direct lateral approach through the psoas muscle. The advantage of LLIF over the traditional anterior approach is the avoidance of exposure of the abdominal viscera, large vessels, and sympathetic plexus. Injury to the nerve roots and dura, and perineural fibrosis, which can occur after PLIF or TLIF, are minimized with this technique 2) 3).

Indications

Used to treat leg pain or back pain generally caused by degenerative disc disease.

LLIF has been utilized to treat a variety of pathologies including adult degenerative scoliosis, central and foraminal stenosis, spondylolisthesis, and adjacent segment degeneration

They have become an increasingly popular surgical technique due to the benefits of minimal tissue disruption, excellent disc visualization, ability to insert a large intervertebral cage to lessen subsidence, and faster recovery times 4) 5).

Position

The LLIF procedure differs from other lumbar procedures in that the patient is positioned in the lateral decubitus position, often times utilizing bending the bed near the iliac crest region in order to facilitate access to the L4-5 disc space.

In awake volunteers, the pressure at the iliac crest or greater trochanter at the break of the bed increases by increasing the bed angle. Women with a lower BMI had high VAS pain scores when their greater trochanter was at maximal bed break. Men with higher BMI had high VAS pain scores when their iliac crest was at maximal bed break. An awareness of the iliac crest or greater trochanter at the break of the bed should be considered to prevent pain and increased pressure based on the patient's sex and BMI 6).

As with most minimally invasive spine procedures, lateral lumbar interbody fusion (LLIF) requires the use of biplanar fluoroscopy for localization and safe interbody cage placement. Computed tomography (CT)-based intraoperative spinal navigation has been shown to be more effective than fluoroscopic guidance for posterior-based approaches such as pedicle screw instrumentation.

Use of an intraoperative cone-beam CT with an image-guided navigation system is feasible and safe and appears to be accurate, although a larger study is required to confirm these results 7).

Complications

The complication rate during the LLIF procedure has been reported to range from 2% to 30% with up to 20% minor and 8.6% major complications 8) 9) 10).

One type of minor complication that can be experienced is related to skin abrasion from tape as the patient is secured to the bed. Surgeons typically tape bony prominences by applying foam pads on the skin but not over truncal regions. Since the patient is asleep for the taping procedure, there is no knowledge about how much pressure applied to the skin can cause pain. A second minor complication is the incidence of pain mimicking that of trochanteric bursitis presumably due to direct pressure of the greater trochanter against the table.

A major complication with LLIF is rhabdomyolysis or muscle necrosis due to prolonged soft tissue pressure which can lead to acute renal failure 11). Rhabodmyolsis can be diagnosed by rising creatine phosphokinase levels and must be quickly identified to initiate appropriate medical treatment.

Subsidence

Intervertebral cage settling during bone remodeling after lumbar lateral interbody fusion (LIF) is a common occurrence during the normal healing process.

Malham et al. distinguished between early cage subsidence (ECS) and and delayed cage subsidence (DCS). Radiographic subsidence (DCS) was categorized using descriptors for the location and severity of the subsidence. Neither interbody fusion rates nor clinical outcomes were affected by radiographic subsidence. To protect patients from subsidence after MIS LIF, the surgeon needs to take care with the caudal endplate during cage insertion. If a caudal bilateral (Type 2) endplate breach is detected, supplemental posterior fixation to arrest progression and facilitate fusion is recommended 12).

Cost effectiveness

TLIF and LLIF produced equivalent 2-year patient outcomes at an equivalent cost-effectiveness profile 13)

Case series

2018

A retrospective review of prospectively collected data was conducted on consecutive patients who underwent stand-alone LLIF between July 2008 and June 2015; 297 patients (623 levels) met inclusion criteria. Imaging studies were examined to grade graft subsidence according to Marchi criteria, and compared between those who required revision surgery and those who did not. Additional variables recorded included levels fused, DEXA (dual-energy x-ray absorptiometry) T-score, body mass index, and routine demographic information. The data were analyzed using the Student t-test, chi-square analysis, and logistic regression analysis to identify potential confounding factors. RESULTS Of 297 patients, 34 (11.4%) had radiographic evidence of subsidence and 18 (6.1%) required revision surgery. The median subsidence grade for patients requiring revision surgery was 2.5, compared with 1 for those who did not. Chi-square analysis revealed a significantly higher incidence of revision surgery in patients with high-grade subsidence compared with those with low-grade subsidence. Seven of 18 patients (38.9%) requiring revision surgery suffered a vertebral body fracture. High-grade subsidence was a significant predictor of the need for revision surgery (p < 0.05; OR 12, 95% CI 1.29-13.6), whereas age, body mass index, T-score, and number of levels fused were not. This relationship remained significant despite adjustment for the other variables (OR 14.4; 95% CI 1.30-15.9). CONCLUSIONS In this series, more than half of the patients who developed graft subsidence following stand-alone LLIF required revision surgery. When evaluating patients for LLIF, supplemental instrumentation should be considered during the index surgery in patients with a significant risk of graft subsidence 14).

2015

A total of 128 consecutive patients (with 178 treated levels in total) underwent MIS LIF performed by a single surgeon. The subsidence was deemed to be ECS if it was evident on postoperative Day 2 CT images and was therefore the result of an intraoperative vertebral endplate injury and deemed DCS if it was detected on subsequent CT scans (≥ 6 months postoperatively). Endplate breaches were categorized as caudal (superior endplate) and/or cranial (inferior endplate), and as ipsilateral, contralateral, or bilateral with respect to the side of cage insertion. Subsidence seen in CT images (radiographic subsidence) was measured from the vertebral endplate to the caudal or cranial margin of the cage (in millimeters). Patient-reported outcome measures included visual analog scale, Oswestry Disability Index, and 36-Item Short Form Health Survey physical and mental component summary scores.

Four patients had ECS in a total of 4 levels. The radiographic subsidence (DCS) rates were 10% (13 of 128 patients) and 8% (14 of 178 levels), with 3% of patients (4 of 128) exhibiting clinical subsidence. In the DCS levels, 3 types of subsidence were evident on coronal and sagittal CT scans:

Type 1, caudal contralateral, in 14% (2 of 14), Type 2, caudal bilateral with anterior cage tilt, in 64% (9 of 14), and Type 3, both endplates bilaterally, in 21% (3 of 14). The mean subsidence in the DCS levels was 3.2 mm. There was no significant difference between the numbers of patients in the subsidence (DCS) and no-subsidence groups who received clinical benefit from the surgical procedure, based on the minimum clinically important difference (p > 0.05). There was a significant difference between the fusion rates at 6 months (p = 0.0195); however, by 12 months, the difference was not significant (p = 0.2049) 15).

1) , 2)
Ozgur BM, Aryan HE, Pimenta L, Taylor WR. Extreme lateral interbody fusion (XLIF): a novel surgical technique for anterior lumbar interbody fusion. Spine J. 2006;6:435–443.
3)
Rodgers WB, Gerber EJ, Patterson J. Intraoperative and early postoperative complications in extreme lateral interbody fusion: an analysis of 600 cases. Spine (Phila Pa 1976) 2011;36:26–32.
4)
Rodgers WB, Gerber EJ. Outcomes of MIS spinal fusion: 12 and 24 months. The Spine Journal. 2010;10(9):S141.
5)
Isaacs RE, Hyde J, Goodrich JA, et al. A prospective, nonrandomized, multicenter evaluation of extreme lateral interbody fusion of the treatment of adult degenerative scoliosis: perioperative outcomes and complications. Spine. 2010;15(35):S322–30.
6)
Tatsumi RL. Lateral Pressure and VAS Pain Score Analysis for the Lateral Lumbar Interbody Fusion Procedure. Int J Spine Surg. 2015 Sep 28;9:48. doi: 10.14444/2048. eCollection 2015. PubMed PMID: 26512342; PubMed Central PMCID: PMC4610324.
7)
Park P. Three-Dimensional Computed Tomography-Based Spinal Navigation in Minimally Invasive Lateral Lumbar Interbody Fusion: Feasibility, Technique, and Initial Results. Neurosurgery. 2015 Mar 23. [Epub ahead of print] PubMed PMID: 25812070.
8)
Youssef JA, McAfee PC, Patty CA, et al. Minimally invasive surgery: lateral approach interbody fusion: results and review. Spine. 2010;35:S302.
9)
Rodgers WB, Gerber EJ, Patterson J. Intraoperative and early postoperative complications in extreme lateral interbody fusion: an analysis of 600 cases. Spine. 2011;1(36):26–32.
10)
Smith WD, Christian GM, Serrano S. Neurologic complications in extreme lateral interbody fusion (XLIF): A comparative analysis of levels L2-3, L3-4, and L4-5. The Spine Journal. 2012;12(9):S124.
11)
Dakwar E, Rifkin SI, Volcan IJ, et al. Rhabdomyolysis and acute renal failure following minimally invasive spine surgery. J Neurosurg Spine. 2011;14:785–788.
12) , 15)
Malham GM, Parker RM, Blecher CM, Seex KA. Assessment and classification of subsidence after lateral interbody fusion using serial computed tomography. J Neurosurg Spine. 2015 Jul 24:1-9. [Epub ahead of print] PubMed PMID: 26207320.
13)
Gandhoke GS, Shin HM, Chang YF, Tempel Z, Gerszten PC, Okonkwo DO, Kanter AS. A Cost-Effectiveness Comparison Between Open Transforaminal and Minimally Invasive Lateral Lumbar Interbody Fusions Using the Incremental Cost-Effectiveness Ratio at 2-Year Follow-up. Neurosurgery. 2016 Apr;78(4):585-95. doi: 10.1227/NEU.0000000000001196. PubMed PMID: 26726969.
14)
Tempel ZJ, McDowell MM, Panczykowski DM, Gandhoke GS, Hamilton DK, Okonkwo DO, Kanter AS. Graft subsidence as a predictor of revision surgery following stand-alone lateral lumbar interbody fusion. J Neurosurg Spine. 2018 Jan;28(1):50-56. doi: 10.3171/2017.5.SPINE16427. Epub 2017 Nov 10. PubMed PMID: 29125429.
lateral_lumbar_interbody_fusion.txt · Last modified: 2018/01/25 13:56 by administrador