1. Arthroscopic release of the Piriformis tendon with intra-operative neuromuscular monitoring Henrique Berwanger Cabrita; Henrique Melo de Camos Gurgel; Daniel Oksman; Ricardo Ferreira Jr; Marcos Leonhardt; Rafael Demura Leal; Julio Marin
University of São Paulo
IOT-HC/FMUSP
Medical School
São Paulo
Brazil

2. Henrique A. Berwanger de A. Cabrita Universidade de São Paulo
(University of São Paulo Medical School )
Brazil
Disclosure: I DO NOT have a financial relationship with any commercial interest.

3. Byrd,T Piriformis Syndrome Oper Tech Sports Med 13:71-79

4. Open dissection of the sciatic nerve under local anesthesia
Open dissection of the sciatic nerve under local anesthesia. The scar was not cosmetic and patients complained of parestesia after the surgery for weeks or months.
Akira Dezawa, M.D., Ph.D., Shinichi Kusano, M.D., and Hiroshi Miki, M.D., Ph.D. Arthroscopic Release of the Piriformis Muscle Under Local Anesthesia for Piriformis Syndrome Arthroscopy: Vol 19, No 5 (May-June), 2003: pp

5. Methods Seven patients (eight hips) operated
All females / mean age was 34.5 years old
All patients complained of buttock pain and sciatica without control of symptoms after a minimal six month period of conservative treatment
Four patients had calf progressive pain and three developed progressive external rotation of the left lower limb.

6. Methods Pre-op electromyography was abnormal in only two patients.
All MRIs were normal, without anatomic variations
All patients had buttock pain and parestesia referred at the leg or the calf at the piriformis test (flexion and internal rotation)
The WOMAC score was used
Minimal follow-up is one year 6

7. Methods
All patients were operated in supine positioning in a fracture table under general anesthesia and intraoperative neurological monitoring.
The electrodes, electroneuromiography and evocated potential monitoring were done by an experienced electrophysiologist (Ferreira, R).
ASIS
Greater Trochanter
Portals for endoscopy of the greater trocanther region.
Three portals are done to acces the posterior aspect of the hip, specially when the piriformis tendon is abriged

8. Arthroscopic access
Portal 1
Portal 2
Tenotomy
Two postero-lateral portals were done to access the perithrocantheric space of the hip. The gluteus medius and external rotators were identified and used as guides to explore the relationship of the Sciatic nerve with the Piriformis tendon. A total release of the Piriformis muscle tendon at the femoral origin was done in all cases with radiofrequency probes.

9. Piriformis tendon release (fluoroscopy)

10. Intraoperative view and tenotomy
Piriformis tendon

11. After the release we can see a better response
H REFLEX
H reflex
INITIAL
FINAL
After the release we can see a better response

14. Results
There were no complications related to the procedure.
Evocated potential confirmed the shortening of elapsed time conduction of the sciatic nerve and amplification of the H reflex in seven hips intra-operatively.
All patients were released from the Hospital at the day after surgery.

15. Results
Physical therapy, including strengthening of hip muscles was instituted immediately.
At last follow up, six of the seven patients had complete relieve of the sciatic pain, with SF-36 evaluations showing 45% improvement in quality of life.
Mean WOMAC score was 78.5 before surgery and 95.6 at last follow up (1-4 years). 15

16. Ponte Estaiada Octavio Frias – São Paulo – SP- Brasil
Conclusion
Arthroscopic release of the Piriformis tendon with intra-operative neuromuscular monitoring is feasible, safe and presented good pain relief.
Ponte Estaiada Octavio Frias – São Paulo – SP- Brasil
Contact:

17. References
Akira Dezawa, M.D., Ph.D., Shinichi Kusano, M.D., and Hiroshi Miki, M.D., Ph.D. Arthroscopic Release of the Piriformis Muscle Under Local Anesthesia for Piriformis Syndrome Arthroscopy: Vol 19, No 5 (May-June), 2003: pp
Hwang DS, Kang C, Lee JB, Cha SM, Yeon KW. Arthroscopic treatment of piriformis syndrome by perineural cyst on the sciatic nerve: a case report. Knee Surg Sports Traumatol Arthrosc May;18(5): Epub 2010 Jan 9.
Sayson SC, Ducey JP, Maybrey JB, et al. Sciatic entrapment neuropathy associated with an anomalous piriformis muscle. Pain 1994;59:
Byrd,T Piriformis Syndrome Oper Tech Sports Med 13:71-79