Download Human amniotic membrane as adjunct to nerve and tendon repair in

Human amniotic membrane as adjunct to nerve and tendon repair in the lower extremity
Lauren Kishman DPM1, Eric Lew DPM1, Mark Hardy DPM FACFAS2
Podiatric Medicine and Surgery, Kaiser Permanente / Cleveland Clinic
2Staff, Department of Foot and Ankle Surgery, HealthSpan Physicians Group, Cleveland Ohio
1Residents,
Cases
Statement of Purpose
Post-operative scar tissue and adhesion development is inherent to foot and ankle
surgery. This complication is particularly problematic following the release of nerve
entrapments and flexor tendon repairs. The development of adhesions following these
procedures is common and the resulting complications significant with recurrent pain,
limited motion and/or neuritis resulting. The ability to limit scar and adhesion formation
following these challenging procedures would have significant positive impact on
patient satisfaction and post-operative outcomes.
Literature Review
The development of post-operative scar tissue and adhesions is inherent to foot and
ankle surgery. Two areas in which this complication is particularly challenging are in the
release of nerve entrapments and flexor tendon repairs. The goal of nerve release
surgery, such as tarsal tunnel release, is to decompress the affected nerve. Postoperative scar formation re-establishes that unwanted incarceration leading to
impedance of vascularity and limitation of nerve gliding thus precipitating the return of
symptomatology1. Due to the commonality of this issue in tarsal tunnel release, the use
of barrier techniques have been advocated to insulate the posterior tibial nerve from
recurrent compression1. Modalities for insulation have included silicone ensheathment
2,3, radial forearm free flap4, and more recently autogenous saphenous vein graft
wrapping5-8. Success rates have been mediocre at best in these modalities with
satisfaction rates averaging 65% with vein wrapping5-8. Unobstructed tendon gliding is
key to tendon function with limitation resulting in recurrent pain, decreased motion and
resulting functional impairment. The use of numerous mechanical barrier products as
well as biochemical products have been advocated to decrease tendon adhesion yet the
literature is mixed with no consensus as to the optimal medium to reduce scar
formation9.
Paramount in the development of adhesions and scar tissue is inflammation. A direct
correlation can be made between the amount of inflammation at a wound site and the
scarring and adhesion that develops10. Human amniotic membrane (HAM) is composed
of a single epithelial layer, a thick basement membrane, and an avascular stroma11.
HAM has been shown to modulate wounds toward fetal healing with anti-inflammation,
anti-scarring, anti-microbial and anti-angiogenesis9, 11. Its use in ophthalmic surgery has
been well established where is has shown to decrease inflammation as well as have
regenerative capabilities11,12. Recent literature has sought to broaden the usage of
amniotic membrane with studies showing successful use in prevention of pelvic and
abdominal adhesions as well as in treatment of burns, ulcerations and trauma. Specific
to our discussion is the use of amniotic membrane to decrease inflammation, adhesions
and scar formation in peri-neural and peri-tendinous tissue. Studies in animal models
have shown significantly less perineural adhesions and fibrosis in nerves wrapped in human
amniotic membrane following neurorrhapy in comparison to control13,14. No studies to date
have been performed on human subjects. In regards to tendon repair, histological
analyses of animal tendon models have shown a significant decrease in adhesions
when augmented with amniotic membrane15,16. A concurrent decreased cellularity of the
inflammatory response and greater organization of fibroblasts and collagen fibers
leading to improved modulus of strength has been cited16
The following are case reports of posterior tibial nerve release and peroneal tendon
repair augmented with cryopreserved human amniotic membrane (Amnoix Medical,
Marietta, GA).
Figure 2a,b. MRI
analysis revealing a high
grade intrasubstance
tear of the peroneus
brevis tendon, without
complete tendon tear or
tendinous retraction as
well as a low grade
intrasubstance tear of
the peroneus longus
tendon
Case 1
65 year old African American male presented with 1 year history of neuropathic pain to
right lower extremity. Denied injury to the area. The patient had nerve conduction
velocity(NCV) tests performed at outside facility, which were consistent with tarsal
tunnel syndrome. He was prescribed Gabapentin with improvement of pain. Past
medical history benign and non-contributory.
Physical examination revealed intact neurovascular status. Negative tinel’s sign upon
percussion of posterior tibial nerve right lower extremity. Minimal pain was elicited to
palpation tarsal tunnel. Ankle and pedal exam otherwise unremarkable.
Radiographs were negative for any boney abnormalities. Review of NCV study
revealed prolonged sensory and distal latency to the abductor hallucis and abductor
digiti quinti muscles consistent with tarsal tunnel syndrome of the right lower extremity.
Operative technique
The patient was placed in the supine position where he underwent general
anesthesia. No tourniquet was utilized. 0.25% marcaine with epinephrine was
infiltrated along the proposed skin incision line. Skin incision was made overlying the
tarsal tunnel. The flexor retinaculum was incised. Blunt dissection was carried down to
the level of the posterior tibial artery, which was identified and retracted for protection.
A moderate amount of varicosities were noted and these were ligated and cauterized
as appropriate. The tibial nerve was identified 4 cm proximal to the medial malleolus
and was freed along its entire course. The nerve was followed until it split into its
terminal branches and dove underneath the abductor hallucis and quadratus plantae
muscles. The nerve was then wrapped with cryopreserved human amniotic
membrane secured with Vicryl suture tacks (Figure 1a,b). The flexor retinaculum was
not reapproximated. Subcutaneous and skin closer were performed in the routine
manner and patient was placed in a posterior splint.
Post-operative course consisted of non-weightbearing in posterior splint for 1 week at
which time patient was transitioned to apropulsive gait in fracture boot. Patient was
allowed full weight bearing following suture removal at 2 weeks post-operatively.
The patient healed without complication and is currently 7 months post-op without
recurrence of neuropathic symptomatology.
Figure 1a,b. Wrapping of the posterior tibial nerve with cryopreserved human amniotic
membrane.
was then allowed apropulsive weightbearing in fracture boot for 4 weeks. The patient
was allowed full weightbearing in boot or brace at 6 weeks post-op. Physical therapy
was instituted at 6 weeks post-op.
Patient healed uneventfully and is currently 5 months post op. She has finished
physical therapy and is currently painfree without signs/symptoms of adhesions.
Figure 3. Peroneus
brevis tendon
ensheathed in human
amniotic membrane
following repair.
Case 2
The patient was a 59 year old African American female who presented with complaint of
pain to the outside of the right ankle x 1 month duration. Patient described pain as
constant and dull in nature with insidious onset. Denied any history of trauma. Previous
treatments had consisted of low dye tapping, anti-inflammatory medications and
immobilization in fracture boot with no significant improvement in symptomatology. Past
medical history was significant for obesity and PVD; otherwise non-contributory.
Upon physical examination, pain was noted to palpation of peroneal tendon course from
posterior to lateral malleolus as well as at insertion into 5th metatarsal base. Pain was
also noted with maximal inversion. Manual muscle testing revealed pain with eversion
though strength was maintained. Pedal and ankle joint range of motion was noted to be
full. Increase in medial longitudinal arch height noted. Physical examination was
otherwise unremarkable.
Radiographic evaluation was positive for findings consistent with high arched foot type
but otherwise unremarkable. MRI analysis revealed a high grade intrasubstance tear of
the peroneus brevis tendon, without complete tendon tear or tendinous retraction as well
as a low grade intrasubstance tear of the peroneus longus tendon (Figure 2a,b).
Operative technique
Patient was placed on the operating room table in the supine position where she
underwent general anesthetic. A midcalf tourniquet was utilized for hemostasis. A
curvilinear skin incision was made along the course of the peroneal tendons at the lateral
aspect right ankle. The peroneal tendon sheath was located. Hypertrophic synovium and
effusion was noted along the course of the tendon sheath. Upon further inspection of the
peroneus brevis tendon, significant fibrosis encompassing approximately 80% of the
tendon with near complete attenuation was noted at its turn near the lateral malleolus.
The longus tendon was noted to be mildly hypertrophic but of normal texture and
contour. The midsubstance of the brevis tendon was unsalvageable and thus excised in
total. Excised tendon was sent for pathology. The proximal and distal aspects of the
brevis tendon were anastomosed with the peroneus longus tendon utilizing a fish scale
technique and fiberwire in buried knot running fashion. A low lying muscle belly was
noted and this was also excised. The anastomosed peroneal tendons were then
wrapped with cryopreserved human amniotic membrane secured with vicryl (Figure 3).
The superficial peroneal retinaculum was repaired and tendons noted to move freely
without subluxation. Deep, subcutaneous and skin closures were performed in routine
fashion. A posterior splint was applied.
Pathology report of excised peroneal brevis tendon was significant for fibrocollagenous
tendinous tissue with myxoid degeneration.
Post-operative course consisted of 2 weeks non-weightbearing in posterior splint. Patient
Analysis and Discussion
Human amniotic membrane has been proven to have anti-inflammatory, anti-scar, and
anti-angiogenic affects with support in the ophthalmic literature11,12. Existing research in
animal models has shown significant decrease in scar and adhesion formation in both
nerve and tendon repair in comparison to control 13-16. To date, there have been no
published studies on the effectiveness of HAM augmentation on nerve or tendon repair
in a human model.
The cases presented here characterize our results in our initial experience with this
product. Similar results have been demonstrated in a case report by Jay on the use of
amniotic membrane augmented for repair of posterior tibial and Achilles tendon repair9.
Given these initial findings, cryopreserved amniotic membrane shows great promise in
the prevention of adhesions and scar formation often associated with post-operative
nerve release and tendon repair.
Future randomized controlled studies into the use of human amniotic membrane on
human subjects need to be undertaken to determine the actual benefit of this product.
References
1. Downey MS. Recurrent Tarsal Tunnel Syndrome: What Now? The Podiatry Institute. 2006, p.113-120.
2. Downey MS. Surgical management of peripheral nerve entrapment syndromes. In Oloff LM, editor: Musculoskeletal Disorders of the
Lower Extremity. Philadelphia: WB Saunders; 1994. 685-717.
3. Merle M, Dellon Al, Campbell JN, Chang PS. Complications of silicon-polymer intubulation of nerves. Micro surg 1989; 10: 130-3.
4. Novotny DA, Kay DB, Parker MG. Recurrent tarsal tunnel syndrome and the radial forearm free flap. Foot Ankle Int 1996; 17:641-3.
5. Campbell JT, Schon LC, Burkhardt LD. Histopathologic findings in autogenous saphenous vein graft wrapping for recurrent tarsal
tunnel syndrome: a case report. Foot Ankle Int 1998;19:766-9.
6. Easley ME, Schon LC. Peripheral nerve vein wrapping for intractable Lower extremity pain. Foot Ankle Int 2000; 21:492-500.
7. Gould JS. Autogenous vein wrapping for painful nerves in continuity. Foot Ankle Clinic. l998;3:527-36.
8. Sotereanos DG, Giannakopoulos P, Mitsionis GI, Xu J, Herndon JH. Vein-graft wrapping for the treatment of recurrent compression of
the median nerve. Microsurg. 1995; l6(11):752-6.
9. Jay RM. Initial Clinical Experience with the use of Human Amniotic Membrane Tissue During Repair of Posterior Tibial and Achilles
Tendons. AFCell. 1-8.
10. Adzick NS, Lorenz HP. Cells, matrix, growth factors, and the surgeon. The biology of scarless fetal wound repair. Ann Surg. 1994;
220(1):10-18.
11. Liu J, Sheha H, Fu Y, Liang L, Tseng S. Update on amniotic membrane transplantation. Expert Rev Opthalmol. 2010; 5(5):645-661.
12. Tseng SCG, Espana EM, Kawakita T, DiPascuale MA, Li W, He H, Liu TS, Cho TH, Gao YY, Yeh LK, Lie CY. How Does Amniotic
Membrane Work? The Occular Surface. 2004; 2(3):177-187.
13. Meng H, Li M, You F, Du J, Luo Z. Assessment of processed human amniotic membrane as a protective barrier in rat model of sciatic
nerve injury. Neuroscience Letters 2011; 496(1) 48–53.
14. Kim SS, Sohn Sk, Lee KY, Lee MJ, ROh MS, Kim CH. Use of Human Amniotic Membrane Wrap in Reducing Perineural Adhesions in
a Rabbit Model of Ulnar Nerve Neurorrhaphy. The Journal of Hand Surgery (European Volume). 2010: 35E(3):214-219.
15. Demirkan F, Colakoglu N, Herek O, Erkula G. The use of amniotic membrane in flexor tendon repair: an experimental model. Arch
Orthop Trauma Surg. 2002; 122:396-399.
16. Yang JJ, Jang EC, Song KS, Lee JS, Kim MK, Chang SH. The Effect of Amniotic Membrane Transplantation on Tendon Healing in a
Rabbit Achilles Tendon Model. Tissue Engineering and Regenerative Medicine. 2010; 7(3):323-329.