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Missed Screw Technique for

Lumbar Fusion

Shoaib Khan

Mr Bhatia

Mr Krishna

Opening of the Stockton and Darlington RailwayPainting in 1880’s, crowds are watching the inaugural train cross the Skerne Bridge in Darlington.

Congreve Matchbox (1827)First Friction match developed by John Walker

Lumbar Spine Disease

• Major public health concern

• Leading cause of disability

• Middle-age working population

• Multiple avenues of treatment

Lumbar Spine Disease

• Degenerative disc disorders

• Secondary changes: Stenosis, Spondylolisthesis, Facet joint OA

Conservative Measures

• Analgesia

• Exercise

• Education

• Physiotherapy

Lumbar Spine Disease

• Surgical treatment stabilization/fusion

• The primary goal of treatment is pain relief and improve function

History of Procedure

• Lumbar Fusion: 7 decades

• Symptomatic Lumbar Spine disease

History of PLIF• 1944, Briggs and Milligan : Laminectomy

• 1946, Jaslow: Spinous Process

• 1953, Cloward: Iliac Crest Autograft

• 1961, Humphreys: Ant lumbar plate

History of PLIF

• 1990’s Interbody Implants and Instruments

• Presently: Synthetic Cages/ Premilled Allograft

Evolution of Technique

• Augmentation with Pedicle Screws

• Stability of Construct

• Increased Fusion rate

History of TLIF

• 1982, Harms and Rolinger• Transforaminal route• Less retraction on thecal sac and nerves• Spares contralateral lamina, facet and pars• Safe for revision cases b/c of its PL trajectory

Indications• Spinal Instability• Spinal Stenosis• Spondylolisthesis• Degenerative scoliosis• Discogenic low back pain• Recurrent Lumbar Disc Herniation • Postdiscectomy collapse with neuroforaminal

stenosis• Pseudoarthrosis

Techniques

• ALIF• PLIF• TLIF• PLF• Circumferential fusion

Biomechanics

• High fusion potential : Grafts are placed under compression

• Interbody fusions place the bone graft in the load-bearing position spinal columns

Spinal Loads and Articular Surface in Lumbar Spine

• Pedicle screw-rod constructs increase biomechanical rigidity and decrease pseudoarthrosis rates

• Interbody fusion devices: Restore intervertebral height and segmental lordosis

Interbody fusion PL fusion

Interbody Grafts Compression

80% 20%

Intervertebral surface area

90% 10%

Vascularity More Less

Sagittal Balance Better Less Better

Interbody vs PL fusion

Relative Contraindications

• Three Level DDD

• Single level disc disease causing radiculopathy without back pain/instability

• Severe osteporosis

Interbody Grafts

• Autologous Illiac crest graft• Structural Allograft• Metallic cages with bone chips• Titanium Mesh Cages• Carbon Fiber Cages• PEEK cages

Interbody Cages

• Provide stability, fills the disc space, require less structural bone graft

• Maintain spinal alignment, neuroforaminal height, prevent graft dislodgement and collapse, enhance fusion rates

• Carriers for osteoinductive or osteoconductive materials

PLIF Technique

• Laminectomy and Facetectomy

• Reveals rostral exiting and caudal traversing nerve roots and disk spaces

 • Thecal sac and nerve roots retracted medially

PLIF Technique

• Discectomy 

• Interbody graft placement

• Pedicle screw-rod compression: restore lumbar lordosis and maintain disk height

PLIF Technique

• Risks of incidental durotomy/nerve injury• Cages : Postoperative Radiculopathy• Bilateral facetectomy to achieve adequate graft

placement• Postoperative Instability and failure if pedicle

screw instrumentation is not added

TLIF Technique

• Unilateral laminotomy and complete facetectomy on the symptomatic side or bilaterally

• Full laminectomy and contralateral foraminotomy

• Discectomy

TLIF Technique

• Posterior bony lips of the end plates may be removed 

• Interbody graft placement

• Pedicle screw-rod compression: restore lumbar

lordosis and maintain disk height

PLIF and TLIF ApproachBottom :TLIF

PL Appraoch for TLIF

Posterior Approach for PLIF

Graft Placement

PL for TLIF

Posterior for PLIF

PLIF Outcome

• Good outcome in properly selected pt

• Fusion rates: 85%

• Comparison of low back fusion techniques: TLIF and PLIF approaches

• Chad D. Cole Todd D. McCall Meic H. Schmidt .Andrew T. Dailey

TLIF Fusion Rate

• Single-level TLIF: More than 90%

• Multilevel procedure: Less than 90%

• Villavicencio AT, Burneikiene S, Bulsara KR, et al: Perioperative complications in transforaminal lumbar interbody fusion versus anterior-posterior reconstruction for lumbar disc degeneration and instability. J Spinal Disord Tech 2006

TLIF vs PLIF

STUDIES HAVE SHOWN THAT THE THERE IS NO STATISTICAL DIFFERENCE IN THE

FUSION RATES OF TLIF Vs PLIF

• Zhang, Qunhu et al. “A Comparison of Posterior Lumbar Interbody Fusion and Transforaminal Lumbar Interbody Fusion: A Literature Review and Meta-Analysis.”BMC Musculoskeletal Disorders 15 (2014): 367. PMC. Web. 22 Oct. 2015

• Park JS, Kim YB, Hong HJ, Hwang SN. Comparison between posterior and transforaminal approaches for lumbar interbody fusion. J Korean Neurosurg Soc.2005;37:340–344.

• Yan DL, Li J, Gao LB, Soo CL. Comparative study on two different methods of lumbar interbody fusion with pedicle screw fixation for the treatment of spondylolisthesis. Zhonghua Wai Ke Za Zhi. 2008;467:497–500.

• Zhuo X, Hu J, Li B, Sun H, Chen Y, Hu Z. Comparative study of treating recurrent lumbar disc protrusion by three different surgical procedures. Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi. 2009;23:1422–1426. 

PLIF Complications

• Transient/ Permanent Nerve Injury• Graft Displacement• Intervertebral space collapse with

neuroforaminal stenosis • Loosening• Subsidence• Pseudoarthrosis

TLIF Complications

• Pedicle screw misplacement• Transient Neurological deficit• Dural/Neural injury• Graft extrusion

Other Complications

• Blood loss• Durotomy• Arachnoiditis • Wound infection• Delayed wound healing• Haematoma• Screw misplacement

Other Complications

• Intraoperative pedicle fracture• Urinary retention• Pulmonary embolism• Seroma• Epidural fibrosis/scar

Our Study

• Rate of interbody fusion using PLIF/TLIF with a missed screw technique.

• Fusion was performed at two levels with no intervening screw at the middle pedicle

Methods

• Retrospective radiological analysis

• Fusion at 2 levels with missed screw technique

• Radiographs were assessed independently by Radiologist and Spinal Surgeon

Assessment Criteria

• Brantigan-Steffee fusion:

-Denser and more mature bone fusion area than originally achieved at surgery

-No interspace between the cage and the vertebral body

-Mature bony trabeculae bridging the fusion area.

Demographics

• Total No: 40• Males: 24• Females: 16 • Avg Age: 44.7 years• Time period: 3 years & 6 months• Mean Follow up: 19.8 months

Cages Used

CARBON FIBER CAGES PEEK CAGES

Results

• Fusion achieved (assessed by Independent Observer)

• 29 patients (76%) at both levels• 3 patients (7%) at one level • No definite fusion was observed in the remaining

6 patients (15%)• 2 excluded from study- inadequate follow up.

• 57 yr old female

• Back pain &

radiculopathy

• L3/4 Spondy

Spondy L3/4Disc DegenerationReduced Disc Height

• MRI L Spine• Disc Degeneration

L3/4,4/5,L5/S1• Minor Disc bulge

L4/5

• 2 level fusion

• Spondy reduced

• 44 yr old male

• Chronic Back Pain

• MRI L Spine• Modic changes

L4/5, L5/S1• Disc bulges

L4/5, L5/S1

• 2 level fusion

• Disc heights maintained

• Lordosis restored

• 64 yr old female

• Chronic Back Pain

• 2 level fusion

Conclusion

Fusion can be achieved without middle pedicle screw while performing PLIF/TLIF

at two levels

THANKS VERY MUCH

UNIVERSITY HOSPITAL OF NORTH TEES