recent advancement in nerve repair

1. Presented by
Cathrine Diana PG I
Dept of oral and maxillofacial surgery

2. Cellular component:
 Neurons- cell body & axon
 Schwann cells
 Connective tissue
 Epineurium
 Perineurium
 endoneurium

4.  Cranial - Motor, sensory, mixed
 Spinal nerves – sympathetic , parasympathetic
 Myelinated , non myeliniated
 Nerve fibres:
 A - alpha – largest fibre, fastest conduction, fine
touch , position
 A-beta – proprioception
 A – delta – sharp pain , fast
 C fibres – slow pain

5.  Classification of nerve injury is based on
 the damage sustained by the nerve
components,
 nerve functionality, and
 the ability for spontaneous recovery

6.  Etiologic
 Seddon’s
 Sunderlands
 Anatomic
 Samii’s
 Histological
 Based on onset(time)

7.  Mechanical injury
 Crush/Compression injury
 Laceration
 Stretch
 High velocity trauma
 Cold injury
 Iatrogenic
 infectious

9. Grade VI – complex peripheral nerve
injury

10. Degree of nerve
injury
Spontaneour
recovery
Rate of recovery Surgery
First neuropraxia Full Days to 3 months none
Second
axonotmesis
full Regenerates at the
rate of
1mm/month
none
third partial Regenerates at the
rate of
1mm/month
None/
neurolysis
fourth none Following surgery
at the rate of
1mm/month
Nerve repair,graft
or transfer
Fifth
neurotmesis
none Following surgery
at the rate of
1mm/month
Nerve repair,graft
or transfer
Sixth –mixed
injury
Recovery &type of surgery vary depends on combination
of degrees of injury

11.  Paralysis- loss of motor function
 Paresis – incomplete loss of motor function
 Anesthesia – loss of all sensation
 Hyperesthesia – excessive sensation
 Hypoesthesia – diminished sensation
 Hyperalgia- excessive sensitivity to painful stimuli
 Hypoalgesia – lowered pain sensitivity

12.  IAN - injured in case of mandibular fractures and
ORIF, tooth extraction, injection, orthognathic
surgeries,minor surgical procedures.
 Lingual nerve – most commonly in third molar
extraction,

13.  Mental N- fracture of mandible, genioplasty,
minor surgical procedures, abnormal pressure
from denture
 Infra orbital N – fracture of infra orbital rim
 ASA/ PSA - osteotomy of maxilla, apicoectomy
 Facial N- penetrating injury, parotid surgeries,
TMJ surgeries
 Auriculo temporal N- TMJ surgeries

14.  Segmental demyelination: it is the selective
dissolution of the myelin sheath segment &
is characterized by slowing of conduction
velocity as nerve impulses travel along the
de
 associated with minor neuropraxia injury of
axons.

15.  It is a process that results when a nerve fibre is cut
or crushed, in which the part of the axon separated
from the neuron's cell body degenerates distal to
the injury. This is also known
as anterograde or orthograde degeneration

16. Some times wallerian degeneration begins in the
most peripheral tissue and progress centrally from
that point – common in trigeminal system caused by
metabolic intoxication like metal poisoning, isoniazid
and penicillin therapy

17.  If the tissue deinnervated for a long period of time
, certain clinical changes may take place, which are
called as neurotophic effect.
 Skeletal muscles – early spontaneous muscle
spasm, flaccid paralysis,with progressive atrophy
and lack of muscle definition and tone.
 Skin & mucosa –cold, dry and inelastic,
susceptibility to injury, poor healing, irregular
keratinization, scaly , cracked skin.

18. Classic physical and occupational therapy:
 Like lubrication, protection of surface tissue from
trauma, manual stimulation of glandular tissue,
warming and temperature control, electric
stimulation of intact motor neuron

19.  Starts at the coaptation site .
 In ideal suituation after injury,
clearance of debris
(by macropages & schwann cells)
spourtings from proximal axon
growth cones by cell elongation

21. secreation of neurotropic factors 7 folds
in 14 days
NGF,BDNF,GDNF
(schwann cells in distal basal lamina)
attraction of GC towards neurotropic
gradient
guided by formation of fibroblast & collagen
matrix
Migration of schwann cell formation
of band of bungner

23. interaction of axon with CAM
Functional reconnection with target at basal
lamina
 The thin nerve fibres will then gradually
thickened to their original diameter,and the
investing schwann cell form the myelin
sheath.

24.  Provocation test of regeneration of nerve
sprouts. Light palpation over suspected area
of injury, produce distal referred tingling
sensation at the target site. – indicate small
nerve fibre recovery. But poorly correlate
with functional recovery, may confused wit
neuroma formation

25.  The growing axonal sprouts may be
inhibited by the scar tissue / foreign
bodies which act as a barrier. When this
happen the growth cone proliferate as
aimless tumour along with the fibrous
tissue to form a tumour called neuroma.

26. Amputation neuroma:

27.  Neuroma incontinuity:
 neuroma along the nerve line – may produce
artificial synapses
 Leads to abnormal chain reaction to original
stimuli. This may be a common explaination
for trigeminal neuralgia,& post traumatic
casualgia.

28.  Lateral adhesive neuroma
 Lateral exophytic neuroma

29.  Anaesthesia dolorosa -it is a constant
boring penetrating or grinding pain in the
distribution of numbness .

30.  Triggered tick like neuralgiform pain:
 some case with in first week after nerve injury, pt
may experience stabbing , flashing pain
secondary to mechanical irritation/ inflammation
in the still intact nerve trunk.
 Peripheral microneurosurgery is effective in pt
with neuromas, pharmacological therapy are
most appropriate in cases of central
neuropathology

31.  means burning sensation
 pain begins at least 2 weeks after penetrating
missile inury in mixed peripheral nerves, region
 due to the artificial synapse of demyelinated
somatic sensory nerve segment with
unmyelinated efferent sympathetic fibre

32.  sense of awareness of missing body part
after amputation is called phantom
phenomenon.
 Paroxysomal stabbing , itching deep
burning of missing part appx 10 mins of
duration. Triggered by tactile sensation

33.  1.Clinical neurosensory testing
 Level A,B,C
 2.McGill pain questionnaire
 3.Visual analogue scale
 4.Electrophysiological testing:
 EMG
 SSEP
 NCS
 5. MRN

34.  Subjective assessment : visual analogue scale
 Objective assessment:
 Level A : static two point discrimination
brush stroke directional
discrimination
 Level B : contact detection
 Level C: pin prick nociception, thermal
discrimination

35. surgicalNon surgical
treatment

36.  Local anaesthesia - EMLA
 Analgesics-The use of analgesics can help patients control
pain
 Anticonvulsants –now a days carbamazepine is the drug of
choice 200- 800 mg/ day
 Corticosteroids – reduce the inflammation
 Narcotic analgesia
 Muscle relaxant
 Tranquilizers – benzodiazepienes used in chronic pain
 Antidepressents

39. Evaluation of Closed Injury

40.  Neurolysis is performed on intra-neural and
extra-neural scar tissue to release
regenerating nerve fibres in the hope of
improving functional recovery
 External
 Internal

41. It is the process of nerve
decompression.
Microdissection of nerve
involves liberation of nerve
from the surrounding scar
tissue , fixation of fracture
segment
Done under magnification 4X
& 8X
turnover epineural sheath tube in primary repair of
peripheral nerves. Ann Plast Surg. 2002 Apr;48(4):392-400
Yavuzer R1esAyhan S (Latifoğlu Ox8Atabay K

42.  Indicated in case of incomplete return of normal
sensory function of previously injured nerve. Under
magnification,12x/ 16x epineurium dissected
longitudinally to release the adhesion around or
within the fascicles

43.  Epifascicular epineurotomy
 Epifascicular epineurectomy
 Inter fascicular epinuerectomy

44.  Goals of Primary nerve repair < 1 wk
 Proper coaptation
 Vascularity
 Free of tension

45.  Failure to perform primary repair
 Late Repair > 1 wk
 Crush injury

46.  Glial scars
 Astrocytes form a barrier preventing further
growth by forming gap junctions
 Tension in the rejoined nerve

47.  Anastomosis of proximal and distal nerve
ending
 Epineurial
 Fascicular
 Perineuial

49.  adequate exposure
 Proper anesthesia
 Magnification with loupes 8x- 10 x
 The nerve ends are then sharply transected
perpendicular to the long axis.
 Minimum of two epineural sutures with 8-0/
9-0 nylon 180° to each other.
 Careful alignment is the critical factor in this
first step

51.  Perineurial repair involves the individual
fascicles and placing sutures through the
perineurium, the protective sheath
surrounding fascicles
 Drawback:
 Trauma to nerve
 Fibrosis
 Tissue reaction

52.  Least accessible fascicle – suture first
 Fewest suture as possible

53.  Single site of suturing
 Better coaptation & vascularity
 Less chance of mismatch & collateral axonal
micro sprouting outside epineurium.

54.  Reconstruction after peripheral nerve injury
may require management of segmental
defects or "gaps" in the injured nerve
 A nerve graft will be about 10 % longer than
the gap between the nerves, and the cross-
section of the nerve end will be a quite larger
than the diameter of the nerve graft to allow
for growth

56.  Sural nerve
 Greater auricular nerve
 Antebrachial cutaneous nerve

57. Donor Nerve
Sural nerve
2.1mm
Greater auricular
N
1.5 mm
Greater auricular
cable
3mm
Inferior alveolar
nerve 2.4 mm
88% 63% 125%
Lingual nerve
3.2mm
66% 47% 94%

58.  .Tension of the suture line and inadequate
preparation of the nerve stumps are the 2 leading
causes of regenerative failure across the suture site,
resulting in poor recovery of nerve function.
 The nerve graft act as a distal nerve stump, so it ll
undergo wallerian degeneration, to provide a conduit
for axon regeneration, schwann cell regeneration is
critical for this

59.  Need for adequate revacularisation – initially occurs
through diffusion from tissue bed reaches
supranormal in 4-5 days.
 Grafr size – in case of increased graft size , central
necrosis occurs due to increased volume of tissue
beyond perfusion
 Sensory loss, scarring and neuroma formation can
cause morbidity to the donor site of the patient the
nerve is harvested from

60.  Primary repair
 Interpositional grafting
 Cross facial nerve repair
 Cross over graft or split graft

61.  The use of allograft nerve material is
particularly appealing because of its available
quantity and lack of donor site morbidity.
 Need for prolonged immunosuppression
required to maintain Schwann cell viability
limits clinical implementation of this method.

62.  Various materials are used as conduits,
 Autogeneous materials – muscles , fascia, veins
collagen
 Alloplastic material –polyglycolic acid,
Polyester,PTFE , scilicone
 Used in case if the gap is
0.5mm- 3mm

63.  Type of injury
 Time of surgery.
 Patient age,
 level of injury,
 mechanism of injury,
 and associated medical conditions all
influence outcome.

64.  evaluated by
 static 2-PD- perceived by Merkel cell,
 , moving 2-PD- Meissner corpuscle
 and pinprick. - Free nerve endings transmit
painful stimuli
 Innervation testing – monofilament testing

66.  Postoperative management after nerve repair
or reconstruction is aimed toward wound
healing, and re-establishing longitudinal
excursion of the nerve
 Repairs are immobilized for approximately 3
weeks by splinting.
 Nerve Repair and Grafting in the Upper Extremity
 S. Houston Payne, Jr., MD
 J South Orthop Assoc. 2001;10(2)

67.  Sensory re-education is designed to help the
patient recognize new input in a useful manner
 Sensory re-education is carried out in three
stages:
 desensitization, early-phase discrimination
 localization, late-phase discrimination
 tactile gnosis

68.  Transcutaneous nerve stimulations (TNS) –
cutaneous bipolar surface electrodes are
placed in painful regions of body &low
voltage electric current is administered.
Best results will obtained if intense of
stimulation is maintained for 1 hour daily >
3 weeks

69.  Coaptation of nerve tissue without suture is
appealing and would potentially eliminate the
trauma associated with traditional suturing
technique. (1) more efficient,
 (2) eliminate variables of tension due to
suture placement and technique,
 (3) improve alignment of fascicles

70.  The two techniques that have been most
carefully evaluated are coaptation by fibrin
glue and by laser gallium-alluminium
arsenide at 820 nm wavelength

71.  Aiding with growth factors – N-acetylmuramyl-L-
alanyl-D-isoglutamine
 Stem cells
 Cell therapy

72.  Frozen nerve repair
 Metabolic manipulations using pulsating electric fields –
include growth factors to influence neurite growth
 Vascularized nerves can be useful to repair nerves longer
than 8 cm and grafts placed in poor vascular beds that are
heavily scarred
 Microsurgery 989;10(3):220-5.
 Sciatic nerve regeneration in the rat. Validity of walking track assessment in
the presence of chronic contractures.
 Dellon AL1, Mackinnon SE

73.  Immediate primary repair in sharp injuries
with suspected transsection of nerve
because delay leads not only to retraction
but also to severe scaring
 Bluntly transsected nerve best repaired after
a delay of several weeks.

74.  A focally injured nerve should be explored if no
functional return within 8-10 weeks
 Decision - making as to whether neurolysis or
resection & repair in a lesion in gross continuity
based on intraoperative electrophysiological
evaluation
 Split repair with usually graft – lesion in continuity
,partial function or undergoing partial regeneration

75.  Careful patient selection for operation
 Nerve anastomosis failure
 ① inadequate resection of scarred nerve
ends
 ② nerve suture distration
 A good end result requiring rehabilitation from
onset of treatment.
 Prevention of disuse, relief of pain, predicting
probable end results of operative procedures

76.  References:
 Peterson’s principle of oral &maxillofacial surgery 2nd edt
 Text book of Oral and maxilla facial surgery – Gustav kruger 6th edt
 Nerve injury and repair – sussan E mackinnon, Washington university school of
medicine
 Peripheral nerve injuries anr repair – Adam osbourn – review of surgeries
 turnover epineural sheath tube in primary repair of peripheral nerves. Ann Plast
Surg. 2002 Apr;48(4):392-400
 Nerve Repair and Grafting in the Upper Extremity S. Houston Payne, Jr., MD J
South Orthop Assoc. 2001;10(2)
 Static and dynamic repairs of fascial nerve injury -Hillary White, Eben Rosenthal-
oral & maxillofacial surgery clinics of north America 25(2013) 303- 312
 Lingual nerve repair to graft or not? Michael millaro DMD et al YJOMS

77. Thank you