High Yield Overview

POSTERIOR LUMBAR DECOMPRESSION AND FUSION (PLDF)

Posterior midline approach with bilateral laminectomy, facetectomy, pedicle screw fixation, and posterolateral fusion | advanced

Critical Danger Structures

Dural Sac & Cauda Equina

Location: Central canal, 2-3mm anterior to ligamentum flavum, conus ends at L1-L2 level

Protection: Identify under-surface of ligamentum flavum before cutting, use Woodson elevator, gentle retraction only, CSF leak risk 5-15%

Nerve Roots (Exiting & Traversing)

Location: Exiting root under pedicle at lateral recess (L4 exits at L4-L5 foramen), traversing root medial descending to next level (L5 exits at L5-S1)

Protection: Decompress lateral recess adequately, identify both roots before instrumentation, avoid excessive retraction, limit facetectomy to <50%

Epidural Venous Plexus

Location: Anterior to dura, valveless Batson's plexus connecting IVC to azygos system

Protection: Abdomen FREE positioning reduces engorgement 50%, bipolar cautery only, avoid aggressive anterior dissection, gelfoam for control

Pedicle Medial Wall

Location: Medial cortex separates pedicle from neural canal, thinnest wall at L5 (1-2mm)

Protection: Proper entry point at Magerl junction, 10-15° medial trajectory (20° at L5), probe all 5 walls, use ball-tip probe, feel cortical breach

Great Vessels (Aorta/IVC)

Location: Anterior to vertebral body, aorta bifurcates at L4, left common iliac vein crosses L5

Protection: Limit pedicle screw depth to 80% vertebral body, avoid anterior cortex breach, use fluoroscopic depth confirmation, 35-40mm typical screw length

Mnemonic

SCREWSSCREWS: Pedicle Screw Safe Insertion

Mnemonic

ABDOMENABDOMEN: Positioning Checklist for Prone Spine Surgery

Indications for PLDF

Primary Indications

Degenerative Spondylolisthesis Grade I-II

Most common indication for PLDF
Associated with spinal stenosis and neurogenic claudication
Instability demonstrated on flexion-extension radiographs (>3-4mm translation)
Failed conservative management for 3-6 months
Evidence: Weinstein SPORT trial showed superior outcomes with fusion vs decompression alone at 4 years

Spinal Stenosis with Instability

Central or lateral recess stenosis with spondylolisthesis
Dynamic instability on flex-ex films
Iatrogenic instability anticipated from extensive decompression (>50% facetectomy)
Multi-level stenosis requiring aggressive facet removal

Recurrent Stenosis After Prior Decompression

Failed decompression alone
Progressive instability post-laminectomy
Residual or recurrent radicular symptoms

Degenerative Scoliosis with Stenosis

Adult degenerative scoliosis >15-20°
Symptomatic stenosis at apex or concavity
Requires decompression and realignment

Contraindications

Absolute

Active infection at surgical site
Severe medical comorbidities precluding safe anesthesia
Patient unable to tolerate prone positioning

Relative

Severe osteoporosis (T-score < -3.5) - may require cement augmentation
Active smoking (increases pseudarthrosis risk 3-4 fold)
Morbid obesity (BMI >40) - increases complications
Severe vascular disease
Previous fusion at adjacent levels

Pre-operative Planning

Imaging Assessment

Standing AP and lateral lumbar radiographs (assess alignment, instability)
Flexion-extension views (>3-4mm translation = instability)
MRI lumbar spine (stenosis severity, disc degeneration, nerve root compression)
CT if bone detail needed (facet arthritis, spondylolysis, previous hardware)

Level Selection

Decompress all symptomatic stenotic levels
Fuse unstable segments only
Consider stopping at L5-S1 vs extending to sacrum (stopping at L5-S1 requires intact disc)

Implant Planning

Pedicle diameter on axial CT or MRI (typically 6-8mm in lumbar spine, smaller at L5)
Screw length: 35-45mm typical (80% vertebral body depth)
Rod diameter: 5.5mm most common
Local autograft usually sufficient for 1-2 level, consider iliac crest or allograft for >2 levels

Step-by-Step Surgical Technique

Step 1: Positioning and Level Confirmation

Patient Positioning

Prone on Jackson table, Wilson frame, or chest rolls
ABDOMEN MUST BE FREE - critical for reducing epidural venous pressure by 50%
Hips extended to reduce lumbar lordosis (easier posterior access)
Padding all pressure points: knees, genitals, breasts, face, eyes
Arms on arm boards <90° abduction or tucked at sides
Head in neutral position (avoid rotation)

Level Confirmation

AP and lateral fluoroscopy BEFORE skin incision
Count from SACRUM upward (L5-S1, L4-L5, L3-L4...)
Mark spinous processes with marking pen
Wrong-level surgery is a NEVER EVENT (0.5-1% incidence)
Document fluoroscopic images in operative record

Exam Pearl

Exam Answer: "Prone positioning with abdomen hanging free is CRITICAL - reduces epidural venous pressure and bleeding by 50%. I confirm the correct level with AP and lateral fluoroscopy BEFORE skin incision, counting from the sacrum upward. Wrong-level surgery is a never event that is entirely preventable with proper imaging."

Positioning Dangers

Wrong-level surgery (0.5-1% incidence) - MUST confirm with fluoro
Pressure injuries (especially face, eyes, genitals)
Visual loss (rare, from prolonged prone position or hypotension)
Brachial plexus injury (arm abduction >90°)
Abdominal compression increases bleeding

Step 2: Midline Incision and Subperiosteal Exposure

Skin Incision

Midline longitudinal incision centered over target spinous processes
8-12cm for single level, longer for multi-level
Through skin, subcutaneous tissue, thoracolumbar fascia in midline

Subperiosteal Dissection

Incise fascia in midline (relatively avascular)
Elevate paraspinal muscles SUBPERIOSTEALLY off spinous processes, laminae, and facets
Use monopolar cautery to release muscle attachments
Expose laterally to transverse processes bilaterally
Preserve posterior ligamentous complex (supraspinous, interspinous ligaments) at adjacent levels

Retractor Placement

Self-retaining retractors (Taylor, McCullough, Cerebellar)
Identify anatomic landmarks: spinous processes, laminae, facets, transverse processes
Adequate exposure for instrumentation and decompression

Exam Pearl

Exam Answer: "Midline approach is relatively avascular. I perform strict SUBPERIOSTEAL dissection to preserve the segmental nerve supply to paraspinal muscles and reduce denervation-related postoperative pain. I preserve the posterior ligamentous complex at adjacent levels to prevent iatrogenic instability."

Exposure Dangers

Excessive muscle stripping = denervation, chronic postop pain
Violation of adjacent level facets or ligaments = iatrogenic instability
Bleeding from muscle if not subperiosteal
Loss of anatomic landmarks

Step 3: Pedicle Screw Insertion

Entry Point Identification (Magerl Point)

Junction of:
- Lateral border of superior articular facet
- Base (junction) of transverse process
Decorticate entry point with burr or curette

Trajectory

10-15° medial angulation (more convergent: 20° at L5)
Parallel to superior endplate on lateral fluoroscopy
"Gear-shift" trajectory - rotate, not just push

Pedicle Preparation

Use awl or starting pedicle probe to penetrate posterior cortex
Advance with gentle rotation ("gear-shift" technique)
Feel for breakthrough - should be smooth resistance
Depth: to anterior 1/3 of vertebral body (35-45mm typical)

5-Wall Probing Technique - CRITICAL

Use ball-tip pedicle probe
Palpate ALL 5 walls:
1. Medial wall (MOST DANGEROUS - neural canal)
2. Lateral wall (psoas, less critical)
3. Superior wall (superior disc space)
4. Inferior wall (inferior disc space)
5. Anterior floor (vertebral body, great vessels)
All walls must be INTACT (solid cortical bone)
If breach detected - redirect or use shorter screw

Screw Insertion

Tap pedicle if dense bone (optional in osteoporotic bone)
Insert appropriately sized screw (6-8mm diameter, 35-50mm length)
80% vertebral body depth is safe
Confirm with AP and lateral fluoroscopy
Screw head should be positioned for rod placement

Exam Pearl

Exam Answer: "Entry point is the Magerl point - junction of transverse process base and lateral superior facet. I use a 10-15° medial trajectory, parallel to the endplate. CRITICAL STEP: I probe and palpate ALL FIVE WALLS before screw insertion - medial, lateral, superior, inferior, and anterior floor. All must be intact. Medial breach is most dangerous as it violates the neural canal."

Pedicle Screw Dangers

Medial breach (5-10%): neural injury, dural tear - MOST DANGEROUS
Lateral breach: into psoas, less critical but weakens fixation
Superior/inferior breach: disc space violation
Anterior breach: great vessels (aorta at L4, IVC, iliac vessels)
Screw too long: anterior cortex perforation, vascular injury

Step 4: Laminectomy

Spinous Process Removal

Remove spinous process at operative levels with rongeur
Save bone for local autograft

Bilateral Laminectomy

Use Kerrison rongeurs (various angles) or high-speed burr
Remove lamina bilaterally from medial pedicle to medial pedicle
Create adequate exposure of dural sac
Thinning technique: thin lamina with burr, then remove with rongeur (safer)

Ligamentum Flavum Removal - CRITICAL TECHNIQUE

ALWAYS identify UNDER surface first (safer approach)
Use Woodson elevator to define plane between ligamentum flavum and dura
Dura is 2-3mm anterior to ligamentum flavum
Incise ligamentum flavum laterally, then peel off medially
Work lateral to medial to progressively visualize dura
Bilateral removal for central stenosis

Decompression Assessment

Adequate central canal decompression
Should see CSF pulsations transmitted to dura
Dural sac should be decompressed and mobile

Exam Pearl

Exam Answer: "The SAFEST technique for ligamentum flavum removal is to identify the UNDER surface first with a Woodson elevator before cutting. This defines the plane anterior to the ligamentum and protects the dura. I then work lateral to medial, progressively exposing the dural sac. Cutting from superficial to deep is dangerous and risks dural tear."

Laminectomy Dangers

Dural tear (5-15% incidence, higher in revision surgery)
Nerve root injury in lateral recess
Epidural venous bleeding (Batson's plexus)
Inadequate decompression
Excessive bone removal = instability

Step 5: Foraminotomy and Nerve Root Decompression

Lateral Recess Decompression

Remove medial portion of superior articular facet (medial facetectomy)
Use Kerrison rongeur or burr
LIMIT to <50% facet resection (>50% = iatrogenic instability)
Decompress both EXITING and TRAVERSING nerve roots

Nerve Root Identification

At L4-L5 level:
- EXITING L4 root: passes laterally under L4 pedicle in foramen
- TRAVERSING L5 root: descends medially, will exit at L5-S1
Both roots must be identified and decompressed

Foraminotomy

Undercut superior articular process of caudal vertebra (L5 at L4-L5)
Remove ligamentum flavum from foramen
Decompress exiting nerve root in foramen
Root should be mobile, free, and pulsating with CSF

Adequacy Check

Pass instrument (e.g., Penfield or ball-tip probe) around nerve root
Root should be completely free circumferentially
CSF pulsations visible
No residual compression

Exam Pearl

Exam Answer: "At L4-L5, I must decompress TWO nerve roots: the EXITING L4 root passing laterally under the L4 pedicle, and the TRAVERSING L5 root descending medially. I perform medial facetectomy to decompress the lateral recess, limiting resection to <50% to avoid iatrogenic instability. The root should be completely mobile and pulsating with CSF when adequately decompressed."

Decompression Dangers

Nerve root injury from traction or direct trauma
Excessive facetectomy (>50%) = iatrogenic instability
Pars interarticularis fracture
Inadequate decompression = persistent symptoms
Dural tear at root sleeve

Step 6: Fusion Bed Preparation

Decortication

Remove soft tissue from transverse processes
Decorticate transverse processes with osteotome or high-speed burr
Remove cortical surface to expose bleeding cancellous bone
Decorticate remaining facet surfaces
Creates posterolateral fusion bed (transverse process to transverse process)

Fusion Surface

Bilateral intertransverse fusion gutters
Adequate bleeding bone surface
Remove all soft tissue that could block fusion

Exam Pearl

Exam Answer: "Posterolateral fusion is the classic lumbar fusion technique - transverse process to transverse process bilaterally. I decorticate with a burr until I see bleeding cancellous bone. The quality of the fusion bed is critical for achieving solid arthrodesis. Local autograft from removed lamina is ideal because it's osteogenic, osteoinductive, osteoconductive, and has no donor site morbidity."

Fusion Bed Dangers

Inadequate decortication = pseudarthrosis
Excessive lateral dissection = segmental vessel injury
Violation of disc space

Step 7: Bone Graft Application

Local Autograft

Use removed lamina, spinous processes, and facets
Morselized into 3-5mm pieces
Excellent graft material: osteogenic, osteoinductive, osteoconductive
No donor site morbidity

Graft Placement

Pack generously into bilateral intertransverse gutters
Place on decorticated transverse processes and facets
Should fill fusion bed completely
Typically 10-20cc per level

Supplemental Graft (if needed)

Allograft (cancellous chips or DBM)
Iliac crest autograft (if local insufficient, e.g., >2 levels)
BMP (rhBMP-2) - expensive, risk of ectopic bone formation, radiculopathy, use with caution

Fusion Rate Expectations

Posterolateral-only fusion: 80-85% at 1 year
Instrumented posterolateral fusion: 85-95% at 1 year
Adding interbody cage: 95%+ at 1 year

Exam Pearl

Exam Answer: "Local autograft from the removed lamina and spinous processes is the IDEAL graft material - it's osteogenic (contains cells), osteoinductive (contains growth factors), osteoconductive (provides scaffold), and has no donor site morbidity. I pack it generously into the intertransverse gutters. Fusion rates with instrumented posterolateral fusion are 85-95% at one year."

Grafting Dangers

Inadequate graft volume = pseudarthrosis (10-15% posterolateral-only)
BMP overuse = ectopic bone formation, radiculopathy, seroma
Graft displacing into canal = nerve compression
Iliac crest harvest = donor site pain, hematoma, infection

Step 8: Rod Placement and Final Construct

Rod Contouring

Contour rods to restore physiological lumbar lordosis (typically 40-60°)
Match patient's sagittal alignment
Avoid flat-back deformity

Rod Insertion

Insert pre-contoured rods into pedicle screw heads
May require slight screw head adjustment
Ensure rod fully seated in screw heads

Compression/Distraction

Compression across spondylolisthesis (reduces slip, compresses graft)
Distraction for foraminal height restoration (carefully - can overdistract)
Typically 1-2mm compression per level

Final Tightening

Tighten all set screws with appropriate torque
Avoid over-torque (can strip threads)
Check construct stability
Cross-links optional (I use for long constructs >3 levels)

Fluoroscopic Confirmation

AP view: screws within pedicle shadows, rod position
Lateral view: lordosis restored, screw depth, construct alignment

Exam Pearl

Exam Answer: "I contour rods to restore physiological lordosis. Compression across the spondylolisthesis helps reduce the slip and compresses the graft for fusion. I ensure all set screws are adequately tightened - loose screws cause construct failure. Final fluoroscopy confirms screw position, lordosis restoration, and overall alignment."

Instrumentation Dangers

Loss of lordosis = sagittal imbalance, flat-back syndrome
Over-compression = nerve root impingement
Under-tightening = construct failure, screw loosening
Rod too short/long = junctional problems
Screw head prominence = soft tissue irritation

Step 9: Final Decompression Assessment

Central Canal

Pass instrument behind dura easily
No residual compression
CSF pulsations visible

Nerve Roots

All roots free and mobile
Pulsating with CSF
Can pass instrument around roots (360° free)

No Construct Compression

Ensure graft not compressing neural elements
Screw heads not impinging on roots

Fluoroscopic Assessment

Lateral view confirms adequate decompression
No residual stenosis on imaging

Exam Pearl

Exam Answer: "Before closure, I perform a final systematic check: central canal adequately decompressed, all nerve roots completely free and pulsating, no compression from graft or hardware. Inadequate decompression is the main reason for failed surgery. The roots should be mobile with visible CSF pulsations."

Final Check Dangers

Inadequate decompression = persistent symptoms
Graft in canal = nerve compression
Hardware impingement on roots
Unrecognized dural tear

Step 10: Hemostasis and Dural Tear Management

Hemostasis

METICULOUS bipolar cautery for epidural veins
Gelfoam for persistent oozing
Avoid aggressive cautery near nerve roots
Patient should be normotensive
Achieve complete hemostasis before closure

Dural Tear Recognition

Look for CSF egress
Visible defect in dura
STOP if identified

Dural Tear Repair - Critical Skill

Small Tear (<5mm, accessible)

PRIMARY REPAIR with 4-0 or 5-0 non-absorbable suture (Prolene, Nurolon)
Running or interrupted technique
Watertight closure
Test with Valsalva maneuver
Cover with DuraSeal or fibrin glue

Large Tear (>5mm) or Accessible

PATCH REPAIR with dural graft:
- Cadaveric dura
- Synthetic (DuraGen, Durepair)
- Autologous fascia (rare)
Suture if possible, seal edges with fibrin glue
Test integrity with Valsalva

Inaccessible Tear (Anterior Dura)

Cannot primarily repair
Apply fibrin glue only
Tight fascial closure
Bed rest 24-48 hours postop
No lumbar drain (controversial, I avoid due to infection risk)

Post-Repair Management

DOCUMENT in operative report
Counsel patient about CSF leak risk
Drain controversial (may increase leak, I avoid if good repair)
Bed rest 24-48hrs if large tear
Monitor for postop headache, CSF leak signs

Exam Pearl

Exam Answer: "If I identify a dural tear intraoperatively, I assess size and accessibility. Small accessible tears are repaired primarily with 4-0 or 5-0 non-absorbable suture and tested with Valsalva. Large or inaccessible tears get fibrin glue and tight fascial closure. I document the tear, counsel the patient, and typically avoid drains as they may increase CSF leak risk. Bed rest for 24-48 hours postoperatively."

Hemostasis/Dural Repair Dangers

Unrecognized dural tear = CSF leak, pseudomeningocele, meningitis
Inadequate hemostasis = epidural hematoma, cauda equina syndrome
Drain with dural tear = persistent CSF leak
Excessive cautery near roots = nerve injury

Step 11: Wound Closure

Irrigation

Copious irrigation with normal saline or antibiotic solution
3-6 liters typical
Remove all debris and bone dust

Fascial Closure - CRITICAL LAYER

Close thoracolumbar fascia with 0 or 1 Vicryl
Strong absorbable sutures
Interrupted or running technique
MUST be watertight, especially if dural tear
This layer bears most tension

Subcutaneous Layer

2-0 or 3-0 Vicryl
Eliminate dead space
Reduce seroma risk

Skin Closure

Staples (most common, easy removal)
Running subcuticular (better cosmesis)
Interrupted sutures

Drain Placement (Optional)

Subfascial drain for multilevel or significant bleeding
I use Blake or Jackson-Pratt drain
Remove when <30ml over 8 hours (typically 24-48hrs)
Controversial if dural tear (may increase CSF leak)

Exam Pearl

Exam Answer: "Fascial closure is the CRITICAL layer - it must be watertight, especially if there was a dural tear. I use strong absorbable sutures (0 or 1 Vicryl). Drain placement is controversial - it may reduce hematoma but slightly increases infection risk. I use drains for multilevel cases or significant bleeding, and remove at 24-48 hours when output <30ml/8hrs."

Closure Dangers

Inadequate fascial closure = wound dehiscence
Wound hematoma = infection risk, dehiscence
Drain with dural tear = CSF leak
Surgical site infection (1-5% in spine surgery)

Exam Viva Scenarios

Practice these scenarios to excel in your viva examination

VIVA SCENARIOStandard

EXAMINER

"A 62-year-old presents 6 hours post PLDF with progressive bilateral leg weakness, saddle numbness, and urinary retention. Drain output was 200ml in recovery but has now stopped. What is your diagnosis and management?"

EXCEPTIONAL ANSWER

This is an EPIDURAL HEMATOMA causing acute CAUDA EQUINA SYNDROME - a surgical emergency. **Immediate Assessment**: Examine lower limbs for motor power (likely bilateral weakness), sensory exam for saddle anesthesia, test perianal sensation, check for urinary retention with bladder scan. **Diagnosis**: Clinical presentation of progressive cauda equina syndrome within hours of surgery. Drain output stopped suddenly - concerning for clot formation. **Emergency Management**: 1. **URGENT MRI lumbar spine** - will show epidural hematoma compressing cauda equina 2. **Immediately contact anaesthetics** - patient needs to return to OR urgently 3. **Return to OR within 6 hours** (sooner is better - outcomes worse if >12hr delay) 4. **Surgical evacuation**: reopen wound, evacuate hematoma, decompress neural elements, meticulous hemostasis, normotensive closure 5. **High-dose steroids controversial** (I do not routinely use) 6. **Postop**: close neuro monitoring, ICU if needed **Prognosis**: Time to decompression is critical. If decompressed within 6-8 hours, most patients recover substantially. Delay >12 hours associated with poor neurological recovery, permanent bladder dysfunction. **Documentation**: Document timing of symptom onset, neuro exam findings, time to OR, consent discussion regarding permanent neurological deficit risk. This is a medico-legal emergency - MUST act immediately.

VIVA SCENARIOStandard

EXAMINER

"Explain the difference between exiting and traversing nerve roots at L4-L5. Why is this clinically important?"

EXCEPTIONAL ANSWER

This is CRITICAL ANATOMY for any spine surgeon. At the L4-L5 disc level, there are TWO nerve roots to consider: **1. EXITING L4 NERVE ROOT**: - This root has already descended from the L3-L4 level - It travels laterally and passes UNDER the L4 pedicle - Exits through the L4-L5 foramen (the foramen is ABOVE the L5 pedicle) - Located in the LATERAL RECESS and foramen - Compressed by: foraminal stenosis (superior articular process of L5 narrowing foramen from below), far lateral disc herniation at L4-L5 **2. TRAVERSING L5 NERVE ROOT**: - This root has just exited the thecal sac at the L4-L5 level - It descends medially through the central canal - It is 'TRAVERSING' the L4-L5 level on its way to exit at the NEXT level (L5-S1 foramen) - Located in the CENTRAL CANAL and medial recess at L4-L5 - Compressed by: central or paracentral disc herniation at L4-L5, lateral recess stenosis **Clinical Importance**: **Pattern of compression at L4-L5**: - Central/paracentral disc herniation → compresses TRAVERSING L5 root → L5 radiculopathy (foot drop, great toe weakness, lateral calf numbness) - Far lateral disc herniation → compresses EXITING L4 root → L4 radiculopathy (knee extension weakness, reduced patellar reflex, anterior thigh numbness) - Foraminal stenosis → compresses EXITING L4 root **Surgical decompression implications**: - Must decompress BOTH the lateral recess (for traversing L5) AND the foramen (for exiting L4) - Medial facetectomy decompresses lateral recess (traversing root) - Undercut superior articular process to decompress foramen (exiting root) - Pedicle screw insertion risks EXITING root injury at foramen **This is why we say: 'The root is named by where it EXITS, not where it traverses.'**

VIVA SCENARIOStandard

EXAMINER

"What are your indications for fusion versus decompression alone in lumbar spinal stenosis? A 68-year-old has Grade I degenerative spondylolisthesis (6mm slip) at L4-L5 with stenosis - what would you recommend?"

EXCEPTIONAL ANSWER

This is a common exam question and the answer is nuanced. **DECOMPRESSION ALONE - Indications**: 1. Stenosis WITHOUT instability (no spondylolisthesis, <3mm dynamic motion) 2. Stable degenerative disease 3. No scoliosis or coronal deformity 4. Preserved disc height 5. No anticipated iatrogenic instability (can preserve >50% facets) **Advantages**: Shorter surgery, less blood loss, faster recovery, no hardware complications, no adjacent segment disease from rigid fixation, lower cost **DECOMPRESSION + FUSION - Indications**: 1. **Degenerative spondylolisthesis Grade I-II** (MOST COMMON indication) - THIS PATIENT 2. Stenosis with scoliosis requiring realignment (>15-20°) 3. Iatrogenic instability anticipated (>50% facetectomy needed for adequate decompression) 4. Recurrent stenosis post-decompression with instability 5. Dynamic instability on flexion-extension (>3-4mm translation or >10° angulation) **Evidence**: - Weinstein SPORT trial (N=304, 4-year follow-up): Fusion + decompression superior to decompression alone for degenerative spondylolisthesis - Greater improvement in ODI, SF-36, satisfaction - Re-operation rate lower with fusion (14% vs 23%) **For THIS Patient (68yo, Grade I spondylolisthesis 6mm, stenosis)**: **Recommendation: POSTERIOR LUMBAR DECOMPRESSION AND FUSION (PLDF)** **Rationale**: - Degenerative spondylolisthesis Grade I with 6mm slip = INSTABILITY present - Decompression alone has high failure rate (20-30% require reoperation for instability) - Age 68 = reasonable surgical candidate - Fusion provides stability and better long-term outcomes **Technique**: - Bilateral decompression (laminectomy + medial facetectomy) - Instrumented posterolateral fusion (pedicle screws + rods) - May add TLIF cage for higher fusion rate and slip reduction if desired **Expected Outcomes**: - 80-90% good to excellent outcomes - Fusion rate 85-95% with instrumentation - Adjacent segment disease risk 2.5% per year **Alternative in select patients**: - Older, low-demand patient with minimal slip (<5mm) and no dynamic instability: could consider decompression alone with close observation - But I would counsel that reoperation risk is higher The key is that instability (spondylolisthesis) predicts poor outcome with decompression alone.

PLDF - Rapid Exam Review

High-Yield Exam Summary

References

Weinstein JN, Lurie JD, Tosteson TD, et al. Surgical compared with nonoperative treatment for lumbar degenerative spondylolisthesis. Four-year results in the Spine Patient Outcomes Research Trial (SPORT) randomized and observational cohorts. J Bone Joint Surg Am. 2009;91(6):1295-1304. PMID: 19487505. Landmark RCT showing fusion + decompression superior to decompression alone for degenerative spondylolisthesis at 4-year follow-up
Ghogawala Z, Dziura J, Butler WE, et al. Laminectomy plus fusion versus laminectomy alone for lumbar spondylolisthesis. N Engl J Med. 2016;374(15):1424-1434. PMID: 27074067. RCT demonstrating superiority of fusion + decompression vs decompression alone for Grade I degenerative spondylolisthesis
Forsth P, Ólafsson G, Carlsson T, et al. A randomized, controlled trial of fusion surgery for lumbar spinal stenosis. N Engl J Med. 2016;374(15):1413-1423. PMID: 27074066. Showed no significant difference between decompression alone vs decompression + fusion for spinal stenosis WITHOUT spondylolisthesis at 2 years
Abdu WA, Lurie JD, Spratt KF, et al. Degenerative spondylolisthesis: does fusion method influence outcome? Four-year results of the spine patient outcomes research trial. Spine. 2009;34(21):2351-2360. PMID: 19934809. SPORT substudy comparing posterolateral vs interbody fusion techniques
Chou R, Baisden J, Carragee EJ, et al. Surgery for low back pain: a review of the evidence for an American Pain Society Clinical Practice Guideline. Spine. 2009;34(10):1094-1109. PMID: 19363455. Evidence-based guidelines for surgical management of degenerative lumbar spine conditions
Gertzbein SD, Robbins SE. Accuracy of pedicular screw placement in vivo. Spine. 1990;15(1):11-14. PMID: 2326693. Classic study defining pedicle screw breach rates and classification system
Kim YJ, Bridwell KH, Lenke LG, et al. Pseudarthrosis in long adult spinal deformity instrumentation and fusion to the sacrum: prevalence and risk factor analysis of 144 cases. Spine. 2006;31(20):2329-2336. PMID: 16985461. Analysis of pseudarthrosis risk factors including smoking, fusion technique, and construct rigidity
Wang JC, Bohlman HH, Riew KD. Dural tears secondary to operations on the lumbar spine. Management and results after a two-year-minimum follow-up of eighty-eight patients. J Bone Joint Surg Am. 1998;80(12):1728-1732. PMID: 9875930. Long-term outcomes of incidental durotomy management strategies
Magerl FP. Stabilization of the lower thoracic and lumbar spine with external skeletal fixation. Clin Orthop Relat Res. 1984;189:125-141. PMID: 6478690. Describes the Magerl point for pedicle screw entry and technique
Martin BI, Mirza SK, Spina N, et al. Trends in lumbar fusion procedure rates and associated hospital costs for degenerative spinal diseases in the United States, 2004 to 2015. Spine. 2019;44(5):369-376. PMID: 30074971. Epidemiology and trends in lumbar fusion surgery, cost analysis, and utilization patterns

Posterior Lumbar Decompression and Fusion (PLDF)