WS 206: US Guidance for Lower Limb Chemodenervation Procedures AAPM&R 2015

Transcription

1 WS 206: US Guidance for Lower Limb Chemodenervation Procedures AAPM&R 2015 Katharine E Alter Rita Ayyangar Elie Elovic Troy Henning John Lesher John McGuire Heakyung Kim Michael Munin Jeff Strakowski

2 Disclosures Katharine Alter: Consultant fees Allergan, Royalties Demos Medical Publishing Elie Elovic: Speaker fees Allergan John McGuire: speaker fee Allergan Jeff Strakowski: speaker fees, Allergan, Royalties Demos Medical Publishing

3 Disclosures: Off Label Use of Botulinum Toxins (BoNT) OnabotulinumtoxinA (OBTA) is approved in the USA for the treatment of upper limb spasticity in adult patients All 4 of the FDA approved BoNT products (OBTA, abobotulinumtoxina, incobotulinumtoxina and rimabotulinumtoxinb ) are approve for the treatment of muscle overactivity in cervical dystonia Currently the use of all of the FDA approved BoNT products is off label for the treatment of spasticity in the lower limb and for the treament of children In other countries BoNTs are approved for the treatment of spasticity in other muscles and in pediatric patients This course will mention off label or unapproved uses of BoNTsCurrently the use of all of the FDA approved BoNT products is off label applications

4 Objectives Provide hands on US Training for Chemodenervation Procedures At the conclusion of the Workshop participants will Be familiar with ultrasound appearance of key muscles and nerves Gain skills in operation and handling of ultrasound transducers Be familiar with various scanning techniques used for procedural guidance

5 Agenda Course agenda Review of US guidance 15 minutes To provide time for hands on scanning an abbreviated review of this information will be presented Hands on US Guidance for lower limb muscles 75 minutes Additional handouts provided online Comparison of Guidance Techniques and Review of Evidence Supporting US Guidance for BoNT* Review of US Guidance/Physics

6 Course Agenda Hands On Scanning 40 minutes: Proximal muscles Iliopsoas/iliacus, adductors, Obturator Nerve, piriformis: 35 minutes Calf muscles Posterior/Medial Gastrocnemius, Soleus, FDL, Tibialis Posterior Posterior tibial nerve Procedural Guidance Techniques 1 station will be set up for procedural guidance practice Rotate to this station when you are waiting to scan

7 Why use US for Chemodenervation & BoNT Procedures? Correct target isolation is important for Efficacy Minimizing risk/adverse events Potentially to reduce Required dose Side effects Traditional localization techniques have recognized limitations B-Mode US is increasingly recognized as a more accurate guidance technique for chemodenervation procedures

8 Why you should consider using US for BoNT Injections? ADVANTAGES OF US GUIDANCE FOR CHEMODENERVATION PROCEDURES

9 US for BoNT Injections: Advantages Improved accuracy Complex/overlapping anatomy obscures muscle identification Small/large patients or children Provides direct assessment of target Location Depth Structures to be avoided Transverse View, Posterior Calf Transverse Scan at groin

10 US for BoNT Injections: Advantages Visualize/isolate target structures Quickly Easily Accurately Less painful Smaller needles Pediatric patients often require no sedation Distract patients during procedure Abdominal Muscles

11 BoNT Injections: Why Use US? Focal dystonia Identify and target individual muscle fascicles Ex: FDS digit 3 vs. 4 US increases accuracy and decreases time to isolate correct muscle fascicles Reduces pain Longitudinal View, FDS FDS longitudinal view, mid forearm Short axis view of needle

12 US for BoNT Injections: Advantages High risk targets Avoid untargeted muscles or structures Vessels/nerves/lung High stakes muscles SCM/Scalenes Oromandibular muscles Pterygoids Psoas/iliopsoas Others SCM Transverse Scan, Out of Plane Injection Transverse View Posterior Calf

13 US for BoNT Injections: Advantages Improved accuracy When localization limited by: Involuntary muscle activity Co-contraction Motor control, patient cooperation US does not require AROM to isolate muscle Muscle identification is based on pattern recognition

14 BoNT Injections: Why use US? Advantages Non-muscle targets: Salivary Glands Correctly isolating gland is critical to reduce the risk of dysphagia Parotid EMG and E-Stim are of no help Submandibular

15 Ultrasound and Procedural Guidance Disadvantages Equipment factors Availability Cost Clinician related factors Lack of experience Steep learning curve Limited access to training specific for BoNT injections Transverse view, proximal forearm

16 Ultrasound for BoNT Injection: Summary Localization techniques Palpation EMG Nerve stimulators Ultrasound All have advantages & disadvantages Best Strategy: Be skilled in multiple techniques Be aware of The limitations of each technique Evidence supporting/refuting the accuracy of the various techniques

17 Comparison of Injection Techniques Palpation EMG Stimulation Sonography Accuracy +/- +/ Practicability + - +/- ++ Availability +/- +/- +/- + Pain + - +/- +++ Speed +/- - +/- ++ Evaluation +/- - +/- +++ Future research

18 See online handout for review ULTRASOUND BASICS

19 Ultrasound Pulse Generation and Piezoelectric Crystals Reception Convert electrical pulses into vibrations Converts returning vibrations back into electrical pulses A linear array of crystals is used to create planar images Returning echoes are processed to create grey scale 2D/3D/4D images

20 Ultrasound Equipment Basics: Soundwaves are produced by piezoelectric crystals Cystal arrays are placed into transducers Transducers Determine the frequency of US waveform ( λ) Frequency of US λ determines Depth of penetration Resolution of the image

21 Appearance of tissues is determined by their acoustic impedance/densisty Speckle from scattering in tissue. L~ λ Weak scattering from blood and fluids with low impedance to US λ Tissues will appears dark or hypoechoic Strong echoes from mirror-like interfaces will appear bright or hyperechoic

22 Ultrasound: Transducer Selection Select size and shape to match the clinical application Size/Shape of transducer Linear: Best for flat surfaces Curvilinear: Best for abdomen/pelvic/gyn Hockey stick: Hand Small irregular surfaces

23 US Basics: Transducer Frequency MHz Depth/Penetration Application cm OB/GYN cm Deep muscles cm Leg 10 5cm Forearm cm Hand, face Select transducer to match required penetration depth MHz for superficial structure Hand, forearm 3-5 MHz for deep muscles Piriformis, iliacus, quadratus lumborum Most transducers have mixed frequencies 3-5, 7-12 etc

24 Transducer Handling/Orientation To correctly orient the transducer on the patient Look for a manufacturer s mark on one end of the transducer The marked end = screen left on display To confirm this orientation: Tap the end of the transducer Observe the location of movement on the display screen to confirm the orientation Notched end

25 US Basics: View convention Top of image is superficial i.e. skin Bottom deeper structures Superficial left Right Deep Transverse view, posterior calf

26 US Basics: View convention Transverse scans How do you place the transducer on the patient? Conventions vary Standard cross sectional imaging Screen left = patient right Simplified cross sectional imaging Screen left = medial left Superficial Deep Right Transverse view, posterior calf

27 US Basics: View convention Longitudinal view Convention Place the transducer on the patient so that Proximal = screen left Distal = screen right Qadriceps tendon and patella Superficial Proximal Distal Deep

28 Holding the transducer Grasp the transducer lightly using your Thumb + index or Thumb + index+ middle finger Do not over grip Keep hand in contact with the patient at all times to avoid slipping Using heel of hand or 4 th and 5 th finger Correct : Maintaining contact with patient Incorrect : No contact with patient

29 Anatomic Plane/Transducer Orientation Longitudinal/Long Axis Transverse/Short Axis

30 US Basics: Tissue Properties Muscle Hypoechoic background (contractile elements/fascicles) Interspersed hyperechoic bands of fibroadipose tissue Long axis CT appears as parallel hyperechoic lines, less uniform than in tendon Short Axis CT intramuscular tendons, aponeurosis appear as bands and streaks Longitudidal view Transverse view Transverse view

31 US Muscle identification Identification of muscles is based on pattern recognition of Contour lines Adjacent structures Bones Vessels Other muscles Real-time Use AROM/PROM to assist muscle identification Pronator teres FCR

32 US Basics: Transducer Orientation Long Axis of Transducer Short Axis of Transducer

33 Scanning Tips/Techniques: Injection Techniques In Plane: Needle Inserted Along Long Axis of Transducer In plane/long Axis needle view: Keep needle parallel to transducer Insert needle at flat angle Poor needle visualization Oblique position Steep angle needle

34 Scanning Tips/Techniques: Injection Techniques Out of plane/short axis needle view: Needle View out of plane Keep needle tip under US beam If needle tip is outside of US beam, visualization is lost May be in untargeted structure or muscle Walk down technique Follow movement of needle tip passing through tissues planes to target

35 Interventional MS Ultrasound: Clinical Pearls Real time injection Whatever technique is used: Keep needle within the ultrasound beam If needle tip is outside of the narrow US beam visualization is lost Tip may not be in target structure

36 Interventional MS Ultrasound: Pearls of Wisdom Larger needles are easier to see than small needles Larger needles hurt more 27g needles are easily seen particularly in an in plane view Non-insulated needles are visualized better than insulated. Etched Needles are also available Small amount of air (.2-.3 ml) helps define needle location Agitate injectate: increases reflection from bubbles Agitating may denature the toxin Billing: In the USA, to charge/bill for US, a picture or cineloop must be saved to document the procedure Billing Code: 76942: Ultrasound for Needle guidance, aspiration

37 MUSCLE REVIEW

38 Iliopsoas Illustration from Ultrasound Guided Chemodenervation, Text and Atlas Demos Medical Publishing. Used with Permission

39 Iliopsoas, Distal Transverse, Proximal Thigh/Distal to Inguinal Crease Transverse Ultrasound Image Psoas Distal Palpation RC.JPG Psoas Distal Tv RC1.JPG Psoas Distal R RC

40 Iliopsoas; Distal Transverse Scan

41 Adductors Adductors, Transverse, Out of plane injection, Add Longus Video Link: adductor s Tv inject.wmv

42 Semimembranosis, Longitudinal Scan Injection, In Plane Picture Link: Semimembranosis Longitudinal BB.png Picture Link: HS longit long axis AS.jpg Semi M LA Inj IPBBt.wmv

43 Semimembranosis, Transverse Scan Injection, Out of Plane Injection HS Transverse, short axis AS.jpg Video Link: SemiTTV Inj OP DF.mpg

44 Medial, Lateral Gastrocnemius Soleus, Tibialis Post

45 Gastrocnemius lateral, Soleus Tibialis Posterior Doppler Doppler US Jpg, 4 y.o. Soleus, Tibialis Posterior, Transverse Junction of Middle 1/3:Distal 1/3 calf Picture Link: gastsoleus tib doppler edit.jpg Picture Link: Gastroc soleus tib post edit.jpg

46 Soleus/Tibialis Posterior 4 y.o. Child Transverse Lower-Middle 1/3 of Posterior Calf Out of Plane Injection, Soleus Picture Link: Soleus Tv OP 4 yo KM Labeled Soleus Tv OP 4yo KM.wmv

47 FDL Tibialis Post Picture Link: FDL LA OP RB Picture Link: Gastroc Tv Scan Localiz IMG_0509.jpg

48 Flexor Hallicus Brevis, Flexor Digitorum Brevis Transverse view, Plantar surface Foot