robotic-assisted spine surgery - russo cme · thoracolumbar surgery. • methods retrospective...
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DISCLOSURE STATEMENT
• I have no disclosures relevant to the current topic
• Neither me nor my immediate family members receive income or other
benefits from industry related to robotic-assisted spine surgery.
WHY?
Efficiency in the ORCost Efficiency
Time Efficiency
Accuracy
Reduced radiation exposure
Deformity
ROBOTIC NAVIGATION
Capture Patients Seeking Less Invasive Surgery
Reduce Radiation Exposure2
Surgeons, staff, and patients
Procedural Consistency
Automate trajectory alignment
Pre-Operative and Intra-Operative Planning
Patient Value = Efficacy * Less Invasiveness
Optimize surgical placement
2 -Helm, Patrick A. "Spinal Navigation and Imaging: History, Trends, and Future.” IEEE 34.8 (2015): 1738-1746.3 –Tian, Nai-Feng, et. al. "Minimally invasive versus open transforaminal lumbar interbody fusion: a meta-analysis based on the current evidence.” Euro Spine J 22 (2013): 1741-1749.4 – O’Toole, John. “Surgical Site Infection Rates after Minimally Invasive Spine Surgery.” J Neurosurg Spine 11 (2009): 471-476
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COST/TIME EFFECTIVENESSA Cost-Effectiveness Analysis of the Integration of Robotic Spine Technology in Spine Surgery
• Objective: Investigate the cost-effectiveness of adding robotic technology in spine surgery to an active neurosurgical practice.
• Methods: The time of operative procedures, infection rates, revision rates, length of stay, and possible conversion of open to
minimally invasive spine surgery (MIS) secondary to robotic image guidance technology were calculated using a combination
of institution-specific and national data points. This cost matrix was subsequently applied to 1 year of elective clinical case
volume at an academic practice with regard to payor mix, procedural mix, and procedural revenue.
• Results: 1,985 elective cases were analyzed over a 1-year period; of these, 557 thoracolumbar cases (28%) were analyzed.
Fifty-eight (10.4%) were MIS fusions. • 41.4% patients had governmental insurance, while 58.6% had commercial insurance. The weighted average diagnosis-related group
reimbursement for thoracolumbar procedures for the hospital system was calculated to be $25,057 for Medicare and $42,096 for
commercial insurance.
• Time savings averaged 3.4 minutes per 1-level MIS procedure with robotic technology, resulting in annual savings of $5,713.
• Improved pedicle screw accuracy secondary to robotic technology would have resulted in 9.47 revisions being avoided, with cost savings
of $314,661. Under appropriate payor mix components, robotic technology would have converted 31 Medicare and 18 commercial
patients from open to MIS. This would have resulted in 140 fewer total hospital admission days ($251,860) and avoided 2.3 infections
($36,312).
• Robotic surgery resulted in immediate conservative savings estimate of $608,546 during a 1-year period at an academic center
performing 557 elective thoracolumbar instrumentation cases.
• Conclusion: Application of robotic spine surgery is cost-effective, resulting in lesser revision surgery, lower infection rates,
reduced length of stay, and shorter operative time.
• Richard Philip Menger, Amey R. Savardekar , Frank Farokhi , Anthony Sin Department of Neurosurgery, Louisiana State University Health
Sciences Center, Shreveport, LA, USA Shriners Hospital for Children, Shreveport, LA, USA
• Neurospine
ACCURACYAccuracy of robot-guided versus freehand fluoroscopy-assisted pedicle screw insertion in
thoracolumbar spinal surgery
• OBJECTIVE The quest to improve the safety and accuracy and decrease the invasiveness of pedicle screw placement in spine surgery has led to
a markedly increased interest in robotic technology. The SpineAssist from Mazor is one of the most widely distributed robotic systems. The aim of
this study was to compare the accuracy of robot-guided and conventional freehand fluoroscopy-guided pedicle screw placement in
thoracolumbar surgery.
• METHODS Retrospective series of 169 patients (83 women [49%])
• Robot-assisted cohort (98 patients, 439 screws), pedicle screws were inserted with robotic assistance.
• Freehand fluoroscopy-guided cohort (71 patients, 441 screws), screws were inserted using anatomical landmarks and lateral fluoroscopic guidance.
• The accuracy of screw placement was assessed based on the Gertzbein-Robbins scale by a neuroradiologist blinded to treatment group. The radiological slice
with the largest visible deviation from the pedicle was chosen for grading. A pedicle breach of 2 mm or less was deemed acceptable (Grades A and B) while
deviations greater than 2 mm (Grades C, D, and E) were classified as misplacements.
• RESULTS:
• Robot-assisted cohort, a perfect trajectory (Grade A) was observed for 366 screws (83.4%). The remaining screws were Grades B (n = 44 [10%]), C (n = 15
[3.4%]), D (n = 8 [1.8%]), and E (n = 6 [1.4%]).
• Fluoroscopy-guided group, a completely intrapedicular course graded as A was found in 76% (n = 335). The remaining screws were Grades B (n = 57 [12.9%]),
C (n = 29 [6.6%]), D (n = 12 [2.7%]), and E (n = 8 [1.8%]).
• The proportion of nonmisplaced screws (corresponding to Gertzbein-Robbins Grades A and B) was higher in the robot-assisted group (93.4%) than the freehand
fluoroscopy group (88.9%) (p = 0.005).
• CONCLUSIONS The authors’ retrospective case review found that robot-guided pedicle screw placement is a safe, useful, and potentially more
accurate alternative to the conventional freehand technique for the placement of thoracolumbar spinal instrumentation.
• Molliqaj, et. al. Department of Neurosurgery, Geneva University Hospitals, Department of Neurosurgery, Göttingen University Hospital, Georg-August-University Göttingen, Germany
• Journal of Neurosurgery
JP
• 72 y/o active female
• Severe lumbar stenosis at L3-4 with
neurogenic claudication
• Radicular symptoms in an L4
nerve distribution (right>left)
• Polio in childhood
• Recently diagnosed with Parkinson’s disease,
but neurologist attributes sxs to stenosis
• Back Pain at lumbosacral junction
PELVIC INCIDENCE
• PI=SS+PT
• Lumbar Lordosis should be +/- 10 degs of pelvic
incidence to balance SVA
• Age adjustment
• What do we need to correct sagittal balance
• LL=2 degs
• PI=55 degs
• Need 53 degs +/- 10 degs
DOES CORRECTION OF PREOPERATIVE CORONAL IMBALANCE MAKE A DIFFERENCE IN OUTCOMES OF ADULT PATIENTS WITH DEFORMITY?• OBJECTIVE: Determine the significance of coronal balance on spinal deformity surgery outcomes.
• SUMMARY OF BACKGROUND DATA: Sagittal balance has been confirmed as an important radiographic parameter correlating with adult
deformity treatment outcomes. The significance of coronal balance on functional outcomes is less clear.
• METHODS: Eighty-five patients with more than 4 cm of coronal imbalance who underwent reconstructive spinal surgery were evaluated to
determine the significance of coronal balance on functional outcomes as measured with the Oswestry Disability Index (ODI) and Scoliosis
Research Society outcomes questionnaires. Sixty-two patients had combined coronal (>4 cm) and sagittal imbalance (>5 cm), while 23 patients
had coronal imbalance alone.
• RESULTS: Postoperatively, 85% of patients demonstrated improved coronal balance. The mean improvement in the coronal C7 plumb line was
26 mm for a mean correction of 42%. The mean preoperative sagittal C7 plumb line in patients with combined coronal and sagittal
imbalan`ce was 118 mm (range, 50-310 mm) and improved to a mean 49 mm. The mean preoperative and postoperative ODI scores were 42
(range, 0-90) and 27 (range, 0-78), for a mean improvement of 15 (36%) (P = 0.00001; 95% CI, 12-20). The mean Scoliosis Research
Society scores improved by 17 points (29%) (P = 0.00). Younger age (P = 0.008) and improvement in sagittal balance (P = 0.014) were
positive predictors for improved ODI scores. Improvement in sagittal balance (P = 0.010) was a positive predictor for improved Scoliosis
Research Society scores. In patients with combined coronal and sagittal imbalance, improvement in sagittal balance was the most significant
predictor for improved ODI scores (P = 0.009). In patients with preoperative coronal imbalance alone, improvement in coronal balance
trended toward, but was not a significant predictor for improved ODI (P = 0.092).
• CONCLUSION: Sagittal balance improvement is the strongest predictor of improved outcomes in patients with combined coronal and sagittal
imbalance. In patients with coronal imbalance alone, improvement in coronal balance was not a factor for predicting improved functional
outcomes.
• Daubs MD, Lenke LG, Bridwell KH, Kim YJ, Hung M, Cheh G, Koester LA. Spine (Phila Pa 1976). 2013 Mar 15;38(6):476-83.
THE IMPACT OF POSITIVE SAGITTAL BALANCE IN ADULT SPINAL DEFORMITY• STUDY DESIGN: This study is a retrospective review of 752 patients with adult spinal deformity enrolled in a multicenter prospective database in
2002 and 2003. Patients with positive sagittal balance (N = 352) were further evaluated regarding radiographic parameters and health status
measures, including the Scoliosis Research Society patient questionnaire, MOS short form-12, and Oswestry Disability Index.
• OBJECTIVES: To examine patients with adult deformity with positive sagittal balance to define parameters within that group that might differentially
predict clinical impact.
• SUMMARY OF BACKGROUND DATA: In a multicenter study of 298 adults with spinal deformity, positive sagittal balance was identified as the
radiographic parameter most highly correlated with adverse health status outcomes.
• METHODS: Radiographic evaluation was performed according to a standardized protocol for 36-inch standing radiographs. Magnitude
of positive sagittal balance and regional sagittal Cobb angle measures were recorded. Statistical correlation between radiographic parameters and
health status measures were performed. Potentially confounding variables were assessed.
• RESULTS: Positive sagittal balance was identified in 352 patients. The C7 plumb line deviation ranged from 1 to 271 mm. All measures of health
status showed significantly poorer scores as C7 plumb line deviation increased. Patients with relative kyphosis in the lumbar region had significantly
more disability than patients with normal or lordotic lumbar sagittal Cobb measures.
• CONCLUSIONS: This study shows that although even mildly positive sagittal balance is somewhat detrimental, severity of symptoms increases in a
linear fashion with progressive sagittal imbalance. The results also show that kyphosis is more favorable in the upper thoracic region but very poorly
tolerated in the lumbar spine.
• Glassman SD, Bridwell K, Dimar JR, Horton W, Berven S, Schwab F. Spine. 2005;30(18):2024-2029.
SURGICAL OPTIONS:
A. Limited posterior osteotomy—
segmental
• Ponte
• Smith-Peterson
B. 3 column osteotomy—focal
• Pedicle Subtraction
C. Vertebral resection with anterior
column reconstruction—focal
More Bony resection→Higher Blood Loss→Increased morbidity
ALTERNATIVE SURGICAL OPTIONS:
• ACR without vertebral resection—a segmental approach
• Anterior approach
• Lateral approach
• Posterior approach?
• Expandable cages
•NO bony resection→Less Blood Loss
SURGICAL PLAN FOR CASE PATIENT
Recreation of normal sagittal and coronal alignment
Decompression of L3-4 segment
2 stage surgical intervention
1.Anterior and lateral interbody fusion with lordotic cages
2.Posterior instrumentation and necessary osteotomies
• Open
• Percutaneous with mini-open
ALRIGHT, THAT CASE LOOKS CRAZY
• Do these principles apply to “normal” spine
surgery???
• New literature indicates that applying these
principles to short segment cases has relevance
and will help decrease the likelihood of future
segmental failure.
TEMPEL, ET AL.
• We found that higher postoperative PI-LL mismatch predicted ALD requiring
surgery. A PI-LL mismatch of more than 11◦ (in our cohort of 159 patients) had
a positive predictive value of 75%, and a mismatch greater than 26◦ had a
100% positive predictive value for the development of ALD requiring surgical
correction.
LETS LOOK AT ANOTHER EXAMPLE: JD: 66 Y/O MALE
Immediate Postop → One month Postop → 6 months postop (now it’s a preop)→ Immediate postop
LL 30 degs, Segmental 0 degs LL 14 degs Segmental 38 degs kyphosis LL 38 degs
TK
• 90 y/o otherwise healthy male
• CC: pain at lumbosacral and thoracolumbar
junction
• Rxs: allopurinol, amoxicillin, vit B-12, levothyroxine,
lisinopril, losartan, Pradaxa, pravastatin,
triamterene-HCTZ
• PSH: CABG with subsequent revision, bilateral TKA
• Remains very active and exercises daily
• Physical Examination:
• No Neurological deficit
• Able to lie on the floor in the supine position with
eventual relaxation and reduction of kyphosis
TREATMENT?
• Surgery?
• Other Options?
• Is it possible to improve spinal alignment with non-surgical methods?
ALRIGHT, BACK TO THE ROBOT . . .IDEAL SCENARIO
Multi-Functional
Imaging Versatility
Unique Real-Time
Information
PITFALLS
• How does the robot work?
• Is it possible for the robot to be wrong
• How?
• Registration
• Technique
BASE STATION CAMERA STAND
Rigid Robot Arm
Active End Effector
Touchscreen
Monitor
NDI
Camera
x4
Stabilizers
PRIMARY SYSTEM
COMPONENTS
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How Does the Robot Work?
Image Capture
• Intraoperative Fluoroscopy• Preoperative CT• Intraoperative CT
Multi-Functional
Unique Real-Time
Information
Imaging Versatility
Providing Real-Time “Information”
1. Active feedback on movement of anatomic reference (DRB)
• DRB disruption = biggest source of navigation failure
Multi-Functional
Imaging Versatility
Unique Real-Time
Information
Surveillance Marker
Dynamic Reference Array
How Does the Robot Work?
Providing Real-Time “Information”
2. Real-time visualization of instruments
Multi-Functional
Imaging Versatility
Unique Real-Time
Information
Passive markers
tracking instruments
How Does the Robot Work?
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Providing Real-Time “Information”
3. Deflection sensing technology for skive prevention
Multi-Functional
Imaging Versatility
Unique Real-Time
Information
Active force
monitoring
Active
movement
monitoring
How Does the Robot Work?
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MAINTAINING NAVIGATIONAL INTEGRITY1. Ensure the patient reference is secure
2. Monitor the patient reference for movement
3. Use good navigation technique
4. Ensure registration fixture is secure
5. Avoid skiving when making the entry hole
6. Use a rigid robotic arm to guide all instruments
7. Leverage Experience
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HOW DOES THE ROBOT WORK?
• Robotic + Navigation Guidance • Active & Adaptable End Effector• Integrated Instruments
Imaging Versatility
Unique Real-Time
Information
Multi-Functional
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