Novacheck Surgical Techniques

To Boldly Go! Indications & Explicit Guidance for Soft- Tissue Surgery Using Gait Analysis I have no disclosures.

Tom F Novacheck, MD Gillette Children’s Specialty Healthcare St. Paul, MN, University of Minnesota [email protected]

Thanks to Jean Stout, Adam Rozumalski, and Mike Schwartz

Schedule Learning Objectives Gait Analysis Guidance for 1. Discuss how biomechanical models contribute to Soft-Tissue Surgery the understanding of surgical indications for soft tissue procedures. • General Principles • 10 min 2. Identify specific gait analysis findings which are & Biomechanical Models indications for psoas, hamstring, & gastrocnemius procedures in the child with CP. • Specific muscles • 40 min (PE, gait data, tx, & reported outcomes) 3. Recognize common pitfalls in decision-making – Hamstrings regarding psoas, hamstring, and gastrocnemius – Psoas procedures in order to avoid adverse outcomes. – Gastrocnemius 4. Recognize current shortcomings in gait analysis • Discussion, Question & Answer • 5 min guided decision making for soft tissue procedures.

Muscle Structure

Muscle structure and pathophysiology

Treatment options

Diagnostic tools GENERAL PRINCIPLES & BIOMECHANICAL MODELS

Copyright: The University of Waikato, 2007

2014 AACPDM Breakfast Session Surgical Tx of Soft Tissue Contractures 1 Novacheck, Stout, Rozumalski, Schwartz Novacheck Surgical Techniques

Muscle Structure Muscle contracture in CP

Pennation angle

• Causes are multifactorial – Innervation – Mechanical – Growth

Muscle contracture in CP Muscle contracture in CP

• In-vivo measurement shows fasicles/ • Reduced muscle size sarcomeres that are not short – Volume • Muscles are smaller – PCSA – Thickness – Belly length

Interventions Diagnostic tools

• Global tone management • Current • Focal tone management – Physical examination – Botox – Musculoskeletal modeling • Casting / stretching • Future • Surgery – Measuring stiffness (ultrasound, mechanical) – Laser diffraction

2014 AACPDM Breakfast Session Surgical Tx of Soft Tissue Contractures 2 Novacheck, Stout, Rozumalski, Schwartz Novacheck Surgical Techniques

Modeling Muscle Geometry Muscle-tendon lengths

• Calculate MTL based on joint positions (kinematics)

Muscle-tendon lengths Example

OpenSim Control data

• Simbios • 83 kids – NIH funded project • Multiple speeds • 92 muscles • Calculate MTL and MTV • Extensively validated • Not all 92 muscles • Adaptable for any gait lab – No back/abdominal muscles • Lengthening rate (velocity) – No foot muscles

2014 AACPDM Breakfast Session Surgical Tx of Soft Tissue Contractures 3 Novacheck, Stout, Rozumalski, Schwartz Novacheck Surgical Techniques

Control data Control data - MTL long

short

Control data - MTV Why? lengthening

shortening

• Quantify the outcome of gastroc recession using musculoskeletal modeling.

Why? Why?

• Knee flexion does not predict RectFem • More likely to have a satisfactory outcome length in SKG after hamstrings surgery if hamstrings were • MTL and MTV was different from control short/slow before surgery

2014 AACPDM Breakfast Session Surgical Tx of Soft Tissue Contractures 4 Novacheck, Stout, Rozumalski, Schwartz Novacheck Surgical Techniques

Effects of walking speed

• More subjects would have been considered • Muscles function to have adequate length/velocity if walking shorter and slower speed were taken into account as spasticity increases

Effectssemimembranosus of walkingsemitendinosus speedbiceps femoris long head Effects of walking speed semimembranosus semitendinosus biceps femoris long head 1.00 1.10 1.10 0.00 1.00 Fas 1.00 0.90 1.05 1.05 -1.00 0.50 t 0.50

1.10 1.00 1.00 1.00 0.00 0.00

Normalized MTL Normalized 1.00 0.95 0.95 0.00 -0.50 -0.50

Normalized MTLdot Normalized Slo

0.90 0.90 0.90 -1.00 -1.00 -1.00 0 20 40 60 80 100 0 20 40 60 80 100 0 20 40 60 80 100 0 20 40 60 80 100 0 20 40 60w80 100 0 20 40 60 80 100

rectus femoris vastus lateralis vastus medialis rectus femoris vastus lateralis vastus medialis 1.30 1.30 1.30 2.00 2.00 2.00

1.00 1.00 1.00 1.20 1.20 1.20

0.00 0.00 0.00 1.10 1.10 1.10 -1.00 -1.00 -1.00

Normalized MTL Normalized 1.00 1.00 1.00

Normalized MTLdot Normalized -2.00 -2.00 -2.00

0.90 0.90 0.90 -3.00 -3.00 -3.00 0 20 40 60 80 100 0 20 40 60 80 100 0 20 40 60 80 100 0 20 40 60 80 100 0 20 40 60 80 100 0 20 40 60 80 100

lateral gastrocnemius medial gas tr oc nemius soleus lateral gastrocnemius medial gas tr oc nemius soleus 1.10 1.10 1.10 1.00 1.00 1.00 1.05 1.05 1.05 Slow 0.50 0.50 0.50 1.00 1.00 1.00 0.00 0.00 0.00

Normalized MTL Normalized 0.95 0.95 0.95 -0.50 -0.50 -0.50 Fast MTLdot Normalized 0.90 0.90 0.90 -1.00 -1.00 -1.00 0 20 40 60 80 100 0 20 40 60 80 100 0 20 40 60 80 100 0 20 40 60 80 100 0 20 40 60 80 100 0 20 40 60 80 100 % Gait cycle % Gait cycle % Gait cycle % Gait cycle % Gait cycle % Gait cycle

Hamstrings

PE Gait data Treatment Reported outcomes INDICATIONS AND EXPLICIT GUIDANCE (HAMSTRINGS, PSOAS, GASTROCNEMIUS)

2014 AACPDM Breakfast Session Surgical Tx of Soft Tissue Contractures 5 Novacheck, Stout, Rozumalski, Schwartz Novacheck Surgical Techniques

Hamstrings Hamstrings PCGR Problem Centric Gait Report: Physical Exam: Gait Data: Physical Exam: Knee Flexion Contracture Popliteal angle – Unilateral/Bilateral

Hamstring Spasticity Knee Extensor Lag (for quadriceps insufficiency) Gait Data: Pelvis Kinematics Knee Kinematics Knee Kinetics Muscle Length & Velocity EMG hamstrings

Hamstrings Hamstrings What Are We Looking For? What Are We Looking For? § Muscle-Tendon Lengths in terminal swing § Muscle-Tendon Lengths in terminal swing that are short, at-length, or long regardless that are short, at-length, or long regardless of knee flexion contracture evidence. of knee flexion contracture evidence.

Hamstrings Hamstrings What Are We Looking For? A Reminder: § Muscle-Lengthening Velocities in mid swing that § Presence of at-length or long muscle-tendon are slow or typical. lengths indicates absence of short hamstrings § Presence of short muscle tendon lengths does not indicate absence of at-length or long hamstrings Barefoot, No assist AFOs, No Assist

Barefoot, Walker AFOs, Walker

2014 AACPDM Breakfast Session Surgical Tx of Soft Tissue Contractures 6 Novacheck, Stout, Rozumalski, Schwartz Novacheck Surgical Techniques

Hamstrings

What If You Don’t Have Muscle Lengths? HAMSTRINGS

Goals of Treatment Medial hamstrings lengthening

• allow extension of the knee in terminal • Semitendinosis swing without progressive posterior • Semimembranosus pelvic tilting • Gracilis • in order to improve step length

Surgical Indications Crouch Gait Pelvic Tilt Muscle Length and Velocity

HAMSTRINGS OUTCOMES

2014 AACPDM Breakfast Session Surgical Tx of Soft Tissue Contractures 7 Novacheck, Stout, Rozumalski, Schwartz Novacheck Surgical Techniques

Baumann (1980) Indications

• Retrospective analysis • Not stated, but… • 34 out of 66 patients • “Surgical correction of the spastic crouch gait should lead to good knee extension during the stance phase of walking…”

Baumann JU, Ruetsch H, Schürmann K. Distal Hamstring Lengthening in Cerebral Palsy. International Orthopaedics (SICOT), 3:305-9, 1980

Outcomes DeLuca (1998) • Knee extension improved throughout gait cycle • Retrospective analysis • 73 patients, spastic diplegia • Four groups – medial hamstrings – medial and lateral hamstrings – medial hamstrings + psoas over the brim of the pelvis (OTB) – medial and lateral hamstrings - psoas OTB

DeLuca PA, Ounpuu S, Davis RB, Walsh JHP. Effect of hamstring and psoas lengthening on pelvic tilt in patients with spastic diplegic cerebral palsy. J Pediatr Orthop, 18:712-18, 1998

Indications Outcomes

Postsurgical Pelvic Position

Medial Only n/c n/c Medial and Lateral Worse n/c

Medial and Psoas n/c Med + Lat + Psoas Better n/c

2014 AACPDM Breakfast Session Surgical Tx of Soft Tissue Contractures 8 Novacheck, Stout, Rozumalski, Schwartz Novacheck Surgical Techniques

Arnold (2006) Indications • Goal of study to Investigate muscle Length/Velocity as indication

Arnold AS, Liu MQ, Schwartz MH, Õunpuu S, Delp SL. The role of estimating muscle-tendon lengths and velocities of the hamstrings in the evaluation and treatment of crouch gait. Gait Posture. 23:273-81, 2006

Outcomes Take Home Message

• Lengthen short/slow hamstrings à improve knee ext.

• Lengthen adequate hamstrings à worsen pelvic tilt

Psoas

PSOAS

2014 AACPDM Breakfast Session Surgical Tx of Soft Tissue Contractures 9 Novacheck, Stout, Rozumalski, Schwartz Novacheck Surgical Techniques

Psoas Psoas PCGR Problem Centric Gait Report: Physical Exam:

Physical Exam: Hip Flexion Contracture (Thomas test) Popliteal angle – Unilateral/Bilateral Hip Flexor Spasticity Gluteus Maximus Strength Gait Data: Pelvis Kinematics Hip Kinematics Hip Kinetics Prediction of Outcome: under development

Goals of Treatment Intramuscular Psoas lengthening (IMPL) at the pelvic brim attain adequate length to allow normal hip extension • oblique incision without increasing anterior pelvic tilt medial to the ASIS

2014 AACPDM Breakfast Session Surgical Tx of Soft Tissue Contractures 10 Novacheck, Stout, Rozumalski, Schwartz Novacheck Surgical Techniques

Intramuscular psoas lengthening at the pelvic brim

• pass right angle clamp around the psoas tendon • transect the intramuscular tendon

Sutherland, DH et al. 1997 – Retrospective repeated- measures design – 17 patients, 29 hips Hip Strength – Recession at pelvic brim Assistive Devices – Adductor tenotomy, Age Hamstring lengthening, Surgical Indications and Rectus transfer on PSOAS OUTCOMES most hips

FIG. 1. A-F: Line drawings of operave technique for psoas recession at the pelvic brim.

Sutherland D, Zilberfarb J, Kaufman K, Wyatt M, Chambers, H. Psoas Release at the Pelvic Brim in Ambulatory Patients with Cerebral Palsy: Operative Technique and Functional Outcome. J Pediatr Orthop, 17:563-70, 1997

Results Surgical Indications

• Not stated, but… – “representative case” given – History • Term delivery • Mild delay in milestones • Persistent bilateral ankle equinus. • Bilateral Achilles tendon lengthenings at age 2 years • Repeat Achilles tendon lengthening at age 6 years – Physical examination • Hamstrings contracture (popliteal angles 140°R and 110°L) • Passive hip extension was limited by 20° B • Deep tendon reflexes exaggerated in the lower extremities – Gait study • Exaggerated stance phase anterior pelvic tilt and hip flexion, knee flexion • Prolonged rectus femoris, hamstring and adductor activity, Iliacus fired continuously

2014 AACPDM Breakfast Session Surgical Tx of Soft Tissue Contractures 11 Novacheck, Stout, Rozumalski, Schwartz Novacheck Surgical Techniques

Novacheck TF, et al. 2002 Surgical Indications

– Retrospective repeated-measures design – 93 limbs from 56 patients – Intramuscular psoas lengthening (IMPL) over pelvic brim • +/- Hamstrings lengthening • Not stated • +/- FDO • No prior Hams./FDO/Rhizotomy

Novacheck TF, Trost JP, and Schwartz MH. Intramuscular Psoas Lengthening Improves Dynamic Hip Function in Children With Cerebral Palsy. J Pediatr Orthop, 22:158-64, 2002

Results Results

• Hip Strength Hip Flexor Index

– 10% loss of hip flexor strength (p<0.05) in reduction Sig. Psoas group Hip Power • Hip Power Hip Extension

Pelvic Tilt

Morais, M et al. 2006 Indications

– Retrospective repeated-measures study • One or more of following from gait data: – 52 limbs, 26 individuals – increase of anterior pelvic tilt – increase of pelvic tilt range of motion – Lack of hip extension at terminal stance.

• Hamstrings lengthening, used to avoid increased ant. pelvic tilt • Thomas test NOT part of indications Morais MC, Godoy W, Santos C. Effects of Intramuscular Psoas Lengthening on Pelvic and Hip Motion in Patients With Spastic Diparetic Cerebral Palsy. J Pediatr Orthop, 26:260-4, 2006

2014 AACPDM Breakfast Session Surgical Tx of Soft Tissue Contractures 12 Novacheck, Stout, Rozumalski, Schwartz Novacheck Surgical Techniques

Results Truong, W et al. 2011

• Anterior pelvic tilt significantly reduced • Retrospective repeated-measures study for independent ambulators, but • 87 Sides increased for those using walking aids • Case vs. Control design

Truong WH, Rozumalski A, Novacheck TF, Beatty C, Schwartz MH. Evaluation of Conventional Selection Criteria for Psoas Lengthening for Individuals With Cerebral Palsy: A Retrospective, Case-Controlled Study. J Pediatr Orthop, 31:534–540, 2011

Results

Indications • Kinematics improved (Case v. Control) for GMFCS III and IV • Reduction in Hip Strength (Case v. Control) for GMFCS III and IV • No difference in Hip Power (Case v. Control)

Schwartz, MH et al. 2012 Indications

• Retrospective repeated-measures study • Indications in form of Predicted Outcome! • 800 limbs statistical model Poor ! !Good! • Case vs. Control design (Random Forest) • Machine learning algorithm to find • Variables related to: optimal indications Age, Speed, Pelvis/ Hip Motion, Swing Phase Knee Flexion

Schwartz MH, Truong WH, Rozumalski A, Novacheck TF. Predicting the outcome of intramuscular psoas lengthening in children with cerebral palsy using preoperative gait data and the random forest algorithm. Gait Posture, 37:473-9, 2012

2014 AACPDM Breakfast Session Surgical Tx of Soft Tissue Contractures 13 Novacheck, Stout, Rozumalski, Schwartz Novacheck Surgical Techniques

Results • Significantly better pelvic kinematics (Case vs. Control) • Potential benefit à 14% more good outcomes GASTROCNEMIUS

Gastrocnemius Gastrocnemius Physical Exam: Plantarflexion Contracture vs. Tightness Plantarflexor Spasticity & Ankle Clonus Plantarflexor vs. Dorsiflexor Strength Foot Deformity Knee Contracture Gait Data: Ankle Kinematics Ankle Kinetics Gastrocnemius/Soleus EMG Knee Kinematics Knee Kinetics

Gastrocnemius Gastrocnemius Physical Exam: Gait Data:!

2014 AACPDM Breakfast Session Surgical Tx of Soft Tissue Contractures 14 Novacheck, Stout, Rozumalski, Schwartz Novacheck Surgical Techniques

Two important confounding factors Gastrocnemius • apparent equinus Gait Data:! – many of the stated clinical indications can also be seen in this case • effects of mid-foot breakdown through the talonavicular (TN) joint – can mask many of these findings – If the ankle cannot dorsiflex satisfactorily, then the excessive and premature forefoot loading leads to • increased mid-foot stresses • excessive range of motion (dorsiflexion and abduction) through the TN joint We must use a multisegment foot model! !

The plantarflexors are very sensitive to lengthening!

!Because of these confounding factors, decision-making for gastrocnemius !lengthening cannot be based !solely on currently available quantitative gait data!

Delp et al 1995

Surgical considerations Special considerations Delp et al 1995! • In hemiplegia, the soleus may also require • one centimeter lengthening of the soleus results in a lengthening. Fortunately, the risk of 50% loss of its force generation capacity overcorrection is lower in hemiplegia than in di- or quadriplegia. • soleus -- particularly sensitive to lengthening • Baker lengthening is more conservative than – bi-pinnate muscle fiber orientation tendo-Achilles lengthening and can be – short muscle fiber lengths considered (Borton et al 2001). – Diplegic/quadriplegic, lengthening rarely required • In late presenting cases, tendo-Achilles lengthening (TAL) may be the only option to • gastroc -- much less sensitive to lengthening and is achieve the necessary amount of lengthening typically the only one that requires lengthening. (rare if a child has been cared for in a coordinated, multidisciplinary center).

2014 AACPDM Breakfast Session Surgical Tx of Soft Tissue Contractures 15 Novacheck, Stout, Rozumalski, Schwartz Novacheck Surgical Techniques

Strayer gastrocnemius recession Baumann

• Medial incision @ muscle belly • Midcalf incision @ muscle/tendon junction of gastroc of gastrocnemius • Develop interval between gastroc • Develop interval between and soleus (beware sural nerve) gastroc and soleus • Divide gastroc fascia (beware saphenous vein) • Extend knee/dorsiflex ankle to 0° • Divide deep gastroc fascia • Repair gastroc to soleus fascia • Extend knee & dorsiflex ankle • Baker sometimes in hemiplegia to 0° • No repair of gastroc fascia Never Tendo-Achilles lengthening in ambulators!!

Goals of Treatment

• Satisfactory length in terminal stance (when it must achieve maximum length)

• Eliminate its deforming effects on the midfoot • Improve stance phase stability by allowing a plantigrade foot position with the knee in full extension

Perry 1974

• Retrospective analysis • 17 patients

Indications Recurrence Quality of studies GASTROCNEMIUS OUTCOMES Perry J, Hoffer M, Giovan P, Antonelli D, Greenberg R. Gait Analysis of the Triceps Surae in Cerebral Palsy. J Bone Joint Surg Am, 56-A: 511-20, 1974

2014 AACPDM Breakfast Session Surgical Tx of Soft Tissue Contractures 16 Novacheck, Stout, Rozumalski, Schwartz Novacheck Surgical Techniques

Indications Outcomes

• “clinical stretch test” (no values/ranges • Improved dorsiflexion range by physical given) exam • Failure to respond / significant recurrence after casting • Improved timing/duration of muscle • Persistent equinus …despite bracing activation

• Additional Study Design Elements – cerebral palsy – four to eighteen years old

Shore (2010) Surgical Indications

• Systematic Review equinus deformity, cerebral palsy, orthopaedic surgery • 35 Articles, 19 used instrumented gait analysis • Not summarized (avg. follow-up 2.8 years) • Most studies were level IV quality (case series)

Shore BJ, White N, Graham KH. Surgical correction of equinus deformity in children with cerebral palsy: a systematic review. J Child Orthop, 4:277-90, 2010

Outcomes Svehlik (2012)

• Recurrent equinus: 0% - 43% (up to 62% in • Retrospective analysis, long-term subgroups) follow-up • Calcaneus: 0% - 36% (up to 80% in subgroups) • Evidence is poor, sparse, heterogeneous, short- • Instrumented gait analysis term, etc…. • 18 patients, 21 limbs • “…greater incidence of recurrent equinus in children with hemiplegia … greater incidence of calcaneal gait and deformity in children with diplegia, particularly following procedures on the

Achilles tendon.” Svehlik M, Kraus T, Steinwender G, Zwick EB, Saraph V, Linhart WE. The Baumann procedure to correct equinus gait in children with diplegic cerebral palsy: Long-term results. J Bone Joint Surg Br, 94-B:1143-7, 2012

2014 AACPDM Breakfast Session Surgical Tx of Soft Tissue Contractures 17 Novacheck, Stout, Rozumalski, Schwartz Novacheck Surgical Techniques

Outcomes Surgical Indications

• Not stated, but… – Inclusion Criteria for Study: • Spastic diplegic CP • Equinus gait • Gross Motor Functional Classification System level I to III; • Ability to walk barefoot without walking aids at least for short distances

– Additional Study Criteria: • full sets of kinematic and kinetic gait data collected pre- operatively and at one, two to three, five, and ten years post- operatively • No further surgical treatment of equinus during the followup period; • No prior treatment with selective dorsal rhizotomy or intra-thecal baclofen.

Outcomes Conclusions

• Extensive history of outcome studies for soft-tissue surgery • Recurrence @ 10 Years – Mixed outcomes – Contradictory reports • “comparable to the short-term results of – Controversy continues • Surgical indications …(Strayer technique) in the study of – Rarely stated Gough, Schneider and Shortland and – when stated, adherence rates not given – Impact of indications on outcomes not assessed those of lengthening of the tendo • Future needs – Better study designs Achillis [Borton, et al., 2001]” – Prospective studies – More long-term outcome studies – Indications: state, evaluate, measure adherence – Role of gait data • Gough ??% • Borton 38%

Goals of soft tissue lengthening Still struggle with • Psoas – attain adequate length to allow normal hip extension without intraoperative decision-making increasing anterior pelvic tilt • Hamstrings • Intraoperative assessment – allow extension of the knee in terminal swing without posterior pelvic tilting in order to improve step length – Feels “really tight” or “not so tight” • Goal attainment • Gastrocnemius – Satisfactory length in terminal stance (when it must achieve – “Ahh … that’s much better. That feels maximum length) looser!” – Eliminate its deforming effects on the midfoot – Improve stance phase stability by allowing a plantigrade foot position with the knee in full extension

2014 AACPDM Breakfast Session Surgical Tx of Soft Tissue Contractures 18 Novacheck, Stout, Rozumalski, Schwartz Novacheck Surgical Techniques

2014 AACPDM Breakfast Session Surgical Tx of Soft Tissue Contractures 19 Novacheck, Stout, Rozumalski, Schwartz