- Anatomy:
- arises from lumbrosacral plexus: L4, L5, S1, S2, S3;
- nerve emerges from pelvis below piriformis & enters thigh between ischial tuberosity & greater trochanter;
- in 10% of patients, the sciatic nerve is separated in greater sciatic foramen by all or part of the piriformis;
- sciatic nerve is accompanied by PFCN & by inferior gluteal artery and its special branch to nerve;
- nerve enters thigh beneath lower border of maximus;
- descends near middle of thigh, lying on adductor magnus muscle & being crossed obliquely by long head of biceps femoris ;
- nerve usually separates in upper part of popliteal space;
- Tibal Nerve Branch:
- from anterion branches of LS plexus: L4, L5, S1, S2, S3;
- 2 branches from tibial division: below quadratus femoris:
- upper branch passes to long head of biceps femoris & upper portion of semitendinosus;
- lower branch: innervates lower portion of semitendinosus & semimembranous & ischiocondylar portion of adductor magnus ;
- Common Peroneal Nerve:
- from posterior branches: L4, L5, S1, S2;
- nerve to short head of biceps femoris arises from lateral side of sciatic nerve (common peroneal portion) in middle of thigh & enters
superficial surface of the muscle;
- Sciatic Nerve in THR:
- protection of sciatic nerve in THR
- nerve injuries from THR
- in THR the sciatic nerve may be injured by excessive tension when extremity has been lengthened significantly, especially in pts w/ DDH ;
- sciatic nerve is at risk during leg lengthening;
- peroneal division is most often affected;
- w/ sciatic nerve injury following THR, keep pts leg flexed over side of bed;
- if injury was due to traction, the nerve may recover in the relaxed position;
- Sciatic Nerver Injury from Kocher Langenbock Approach;
- sciatic nerve palsy from Kocher Langenbock Approach;
- can be prevented by intraop monitoring of amount of tension applied by assistants retracting the nerve;
- early treatment consists of AFO
- sciatic nerve recovery may occur over a 3 yr period;
- tendon transfers are usually not performed unitl 3 yr post op
- References:
Sciatic nerve palsy after total hip arthroplasty: treatment by modular neck shortening.
Nerve palsy associated with total hip replacement. Risk factors and prognosis.
Contributory factors and etiology of sciatic nerve palsy in total hip arthroplasty.
Somatosensory-evoked potential monitored during total hip arthroplasty.
Sciatic paralysis. A complication of bleeding following hip surgery.
Paralytic drop foot and gluteal fibrosis after intramuscular injections.
Sciatic Nerve Resection. Is That Truly an Indication for Amputation?
Sciatic Nerve Release Following Fracture or Reconstructive Surgery of the Acetabulum