R. Todd Allen, M.D., PhD Associate Professor, Orthopaedic Surgery UC San Diego Health System

Transcription

1 R. Todd Allen, M.D., PhD Associate Professor, Orthopaedic Surgery UC San Diego Health System

2 Disclosures Consultant/SAB: Intrinsic Therapeutics Johnson & Johnson, DePuy Spine Fellowship Support: Globus Medical NuVasive, Inc. J&J/DePuy Synthes spine

3 LLIF Preparation: same way every time Review radiographs for feasibility of approach Safe Access Left-side approach is default---unless L4 tilt or concavity of scoli influences to right MRI/CT review for vascular/neuro anatomy, Confirm no prior retroperitoneal disease/surgery (e.g., nephrectomy)

4 Preop Radiographs Beware the high iliac crest for L4-5

5 Cautions / Limitations Pelvis too high Severe osteoporosis Bony landmarks difficult to see Endplate prep challenges Subsidence risk Transitional anatomy

6 Left or Right-Sided Approach Left- or Right-Sided Approach with Deformity? Approach side that looks easiest to access on x-rays For degenerative scoliosis cases: Primarily dictated by L4-5 tilt Must scrutinize vascular structures even more Evaluate rotational challenges to perpendicular approach to disk space CONCAVE SIDE as a general rule L4-5 not accessible from convex side Minimizes number of incisions, but tight access to disc Clears the crest

7 Relevant Anatomy Overview: Axial MRI!

8 Relevant Anatomy Image by Uribe et al, SOLAS (2009)

9 Caution: Transitional Anatomy Normal Transitional vs.

10 LLIF: Prepping the OR Anesthesia discussion ahead of time Use succinylcholine preferentially Avoid non-depolarizing, competitive blockade (i.e., vecuronium, etc) Ensure fluoro tech has system on/ready before patient enters room OR staff need to know setup scheme

11 Patient Positioning & Room Set- Up

12 Patient Positioning Rotate patient on flat table to identify approximate true lateral and true AP patient position Position greater trochanter at table break Do NOT break table until patient taping is complete MINIMIZE TABLE BREAK - USE INSTRUMENTS TO WORK AT ANGLE IF NEEDED

13 Patient Positioning Always tape before breakin table. I. Crest Always position iliac crest above table break. A B C D Over the greater trochanter Over the thorax From the greater trochanter to the knee From the table to the knee, past the ankle, then to the table

14 Original Positioning: Try NOT to do this

15 AP/Lateral Imaging True AP image Use cross-table fluoro image (0º) Adjust table left/right tilt Do not adjust C-Arm! True AP indicators Midline spinous process Symmetrical pedicles In multi-level cases, will likely need to readjust table for perfect image at each level

16 AP/Lateral Imaging Matching Lordotic Angles with C-Arm Key L4-5 C-Arm Angle L3-4 C-Arm Angle L2-3 C-Arm Angle

17 AP/Lateral Imaging True Lateral image C-Arm perpendicular to floor (90º) Adjust table Trendelenberg Do not adjust C-Arm! 1 3 True Lateral Indicators: Superimposed pedicles Linear endplates Linear posterior cortex 2 In multi-level cases, will likely need to readjust table for perfect image at each level Incorrect

18 Localization Recall: try to minimize table break

19 Localization

20 TWO INCISION TECHNIQUE RECOMMENDED Confirm Neuromonitoring Working Before Incision!!!

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22 Neuroanatomy: Sensory Ilioinguinal nerve Iliohypogastric nerve 1. Transverse abdominus 2. Internal oblique 3. External oblique Iliac crest DON T USE ELECTROCAUTERY FOR LATERAL INCISION MUSCLE DISSECTION!!

23 Dilator Targeting Guide dilator down to top of psoas with posterior incision finger Dock on psoas generally toward middle to anterior half of muscle belly Dilate slowly with circumferential rotation of stimulated dilator Once down to disk, gently drag dilator back to optimal position

24 Directionally confirm plexus is DORSAL to dilators/retractor Visually reconfirm once retractor is down, as well, but retest!!! Visual assessment alone can miss branches ventrally. Shallow docking and anterior to psoas techniques = higher neuro complication rates (Briseno et al, 2012)

25 Retractor Placement 1. Confirm placement on AP/lateral 2. Minimize opening to only needed space

26 L4-5: USE ANGLED APPROACH EQUIPMENT ALLOWS YOU TO KEEP THE PSOAS AND LUMBAR PLEXUS IN RELAXED STATE (NO TENSION)

27 Steps to Efficient Disc Prep & Implantation 1. Annulotomy 2. Cobb Elevator (no picking first) 3. Pituitary (removal of bulk of disk) 4. Trial 5. Final End Plate Preparation 6. Implantation Minimize average retractor time

28 EFFICIENCY OF RETRACTOR TIME Center blade study, Uribe Greater than minutes of retraction time most substantially associated with neurologic symptoms (or potential for neuro Sx s) KEEP RETRACTION TIME DOWN! (less than 25 minutes)

29 Prior to Closure Irrigation (minimal) Hemostasis / Wound inspection during retractor removal STEP 1: drop retractor excursion a few clicks; if no bleeding STEP 2: pull retractor off spine 1-2mm and hold for 3-5 seconds STEP 3: if no bleeding, remove retractor

30 When to Abort: The procedure or approach If there is no safe corridor Uncertain anatomy Too oblique an angle Can t open / enter disc space If there are neural elements on the annulus (and can t move them) If monitoring fails or doesn t make sense dissect under direct visualization, increase incision size or abort

31 Tips and Tricks Follow the steps of the procedure Patient positioning is critical Don t overbreak the table Single passage through psoas, no wanding Utilize directional neural detection Minimize retractor opening for efficient discectomy Utilize angled instruments (rather than table break Pay attention to RETRACTION TIME!

32 Thank You

33 Important LLIF Advantages & Results: Indirect Decompression Reduction of Vertebral bodies utilizing ligamentotaxis of ALL and PLL

34 Powerful Indirect Decompression Central and foraminal Gains maintained with low subsidence (apophyseal to apophyseal ring cage fit)

35 High fusion rates, Stable interbody cages, Lower subsidence rates, Indirect Decompression Placement of large cage across apophyseal rings (cortical bone) ALIF Dimensions 21-24mm AP 32-36mm wide PLIF/ TLIF Dimensions 25-35mm AP 10-12mm wide Lateral Access Cages Dimensions 18-22mm AP 45-60mm wide

36 Lower Subsidence Rates with LLIF vs PLIF/TLIF 30% endplate cage coverage = decreased subsidence TLIF / PLIF 22% Subsidence 7 LLIF (22mm) 2% Subsidence 8 Vaidya R, Sethi A, Bartol S, Jacobson M, Coe C, Craig JG. Complications in the use of rhbmp-2 in PEEK cages for interbody spinal fusions. J Spinal Disord Tech 2008;21: Le TV, Baaj AA, Dakwar E, Burkett CJ, Murray G, Smith DA et al. Subsidence of polyetheretherketone intervertebral cages in minimally invasive lateral retroperitoneal transpsoas lumbar interbody fusion. Spine 2012;37: Uribe et. al., 2012

37 TIPS & PEARLS: Lessons Learned Identify psoas, nerves, and vessesl (pre-op MRI) Patient positioning is Critical Tape before breaking table Don t overbreak table Rotate table and not C arm Single passage through psoas, no wandering in AP plane Utilize directional neuromonitoring Minimize retractor opening & RETRACTION TIME! Use angled instruments as needed Don t oversize graft, especially with open osteotomies posteriorly

38 LLIF: What we know and what we don t Deformity Correction: LLIF corrects Coronal deformity better than sagittal usually (But can add ACR) Better realignments with open (facetectomies / Smith- Peterson) posterior methods vs percutaneous methods Patients with Spondylolisthesis have Propensity for Sagittal imbalance Lim et.al 2014

39 RESULTS In Elderly Patients complication rates in older patients undergoing open decompression & fusion procedures: PLIF (complications): Okuda: 25% in 251, ave age 61 Benz et al: 41% in >70 yrs Smith and Hanigan: 33% in > 70 yrs Deyo et al: in >75 yrs Raffo & Lauerman: 20% major complications in >80 yrs Posterior Decompression/Fusion: Carreon, et al: 80% in > 65 yrs! Rodgers, et al, Spine 2010

40 LLIF Complications Adult Degenerative Scoliosis Isaacs, et al. Spine pts (prospective, level II) Age >60 Cobb Ave 24 76% with Pedicle Screws 64% perc (MIS) 36% open

41 Major Complications 12% (13 pts) 2 medical, 12 surgical 2.8% (3) deep infections (all in open posterior gp) MIS posterior 9% -- 1 or more complications Open Posterior 21% -- 1 or more complications (3 deep infections) Isaacs, et al. Spine 2010

42 LLIF Complications Adult Degenerative Scoliosis Re-Op: 2.8% (all for deep infections, open gp) No infections in posterior MIS (Perc) No Strokes, No PEs, No deaths

43 MIS Post Patients: Neurologic Injury Mild transient psoas weakness % LE weakness > than a few months % Persistent weakness uncommon 1 of 107 ( to 4/5 manual muscle strength at 6 mo) Lumbar Plexus injury rare: 0.3% per level risk increases in proportion to # of levels performed) (recommend neuromonitoring in all cases)

44 MIS in Octogenarians (Rodgers et al, Spine, 2010) Ave Age = Open PLIFs vs 40 XLIFs: All but 3 (92.5%) MIS pts dc d HOME All PLIF pts went to SNF Complication rate: 7.5% XLIF 60% PLIF -!! Post-op mortality significantly related to incidence of: infection, complications, EBL All greater in PLIF

45 Complications in Lateral Interbody Fusions (Rodgers et al, Spine, 2011) 600 cases (741 levels), 69% included L4-5 99% with posterior fixation Overall Complication Rate: 1.5%(9) surgery related 2.8% (17) medical events 1 st 6 weeks: 6.2% NO wound infections, deaths, intra-op visceral injuries 1.8% (11) additional procedures/re-operation

46 Akbarnia et al (IMAST, 2010) 2 yr f/u, Ave cobb: in SRS-22, VAS & ODI Coronal L4 tilt: % coronal correction w lateral IB alone 70% w posterior instrumentation

47 RESULTS: Coronal and Sagittal Plane alignment after LLIF Significantly coronal alignment: segmental, regional, and globally regional lordosis/global sagittal alignment with OPEN techniques (not necessarily with Percutaneous or MIS techniques Significantly more segmental and regional lordosis of L spine when osteotomies are performed (Attenello, Chang, Lee, Garfin et al. 2013) Acosta et al Lee, Kim, et al

48 LLIF in Adult Degenerative Scoliosis Phillips, Isaacs, et al. Spine month f/u of Isaacs et al, prospective study Significant improvements in: ODI, SF-36 PCS & MCS, VAS back, leg pain scores, (P < 0.001). 85% satisfied with their outcome and would undergo procedure again In hypolordosis pts: LL at 24 months (P < 0.001). Overall Cobb angle corrected 21 15, with the greatest correction observed in patients supplemented with bilateral pedicle screws.