Development of Unilateral Piriformis Syndrome in a Female with Congenital Leg Length Discrepancy

Background: This is a rare case of piriformis syndrome. We discuss the patient’s symptoms, imaging study results, laboratory examination findings, and prescribed treatment in an attempt to determine the possible mechanisms or reasons for this patient’s development of piriformis syndrome. Methods: The patient is a 22-year-old female soldier who was admitted for lower back pain with soreness radiating to her right buttock and right lower extremity. We found that she had leg length discrepancy under X-ray finding. She was diagnosed piriformis syndrome by physical examination and Magenetic Resonance Image. Results: We performed scanography for lower extremities revealed a left femur length of 42.7 cm, a right femur length of 43.3 cm, a left tibia length of 33.2 cm, and a right tibia length of 33.6 cm;her left lower extremity was 1 cm shorter than her right. The MRI of sacrum also reveals hypertrophy of right piriformis muscle. Conclusions: Piriformis syndrome might be caused by short-term compensation in congenital leg length discrepancy. The patient with leg length discrepancy changed posture when standing, walking, and running. These compensation postures could lead to abnormality position of bones where there is insertion of the muscle.

A minimally invasive surgical approach for the treatment of piriformis syndrome: a case series

Background:Piriformis syndrome accounts for approximately 6%of patients who present with sciatic pain.There are many treatment options ranging from physical therapy,to trigger point injections,to surgical intervention.We discuss a surgical method that represents a minimally invasive technique for the treatment of piriformis syndrome.Methods:We describe a novel operative approach and technique for release of the piriformis muscle in the treatment of piriformis syndrome.Described are the preoperative planning,incision and approach,and technique for identifying and releasing the piriformis muscle.Results:Three patients were treated for piriformis syndrome using the described technique.Each patient displayed successful relief of their symptoms immediately following the surgical procedure and at delayed follow-up.Conclusion:Early experience with our method of piriformis release suggests that it is well suited for the treatment of piriformis syndrome.The novel integration of pre-operative trigger point localization coupled with intraoperative neuromonitoring allows effective pain relief with minimal morbidity.

Anatomical study of sciatic nerve and common peroneal nerve compression

BACKGROUND： Many diseases of the common peroneal nerve are a result of sciatic nerve injury. The present study addresses whether anatomical positioning of the sciatic nerve is responsible for these injuries. OBJECTIVE： To analyze anatomical causes of sciatic nerve and common peroneal nerve injury by studying the relationship between the sciatic nerve and piriformis. DESIGN, TIME AND SETTING： Observe and measure repeatedly. The experiment was conducted in the Department of Anatomy, Tianjin Medical College between January and June 2005. MATERIALS： Fifty-two adult cadavers 33 males and 19 females, with a total of 104 hemispheres, and fixed with formaldehyde, were provided by Tianjin Medical College and Tianjin Medical University. METHODS： A posterior cut was made from the lumbosacral region to the upper leg, fully exposing the piriformis and path of the sciatic nerve. MAIN OUTCOME MEASURES： （1） Anatomical characteristics of the tibial nerve and common peroneal nerve. （2） According to different areas where the sciatic nerve crosses the piriformis, the study was divided into two types-normal and abnormal. Normal is considered to be when the sciatic nerve passes through the infrapiriform foramen. Remaining pathways are considered to be abnormal. （3） Observe the relationship between the suprapiriform foramen, infrapiriform foramen, as well as the superior and inferior space of piriformis. RESULTS： （1） The nerve tract inside the common peroneal nerve is smaller and thinner, with less connective tissue than the tibial nerve. When pathological changes or variations of the piriformis, or over-abduction of the hip joint, occur, injury to the common peroneal nerve often arises due to blockage and compression. （2） A total of 76 hemispheres （73.08%） were normal, 28 were abnormal （26.92%）. The piriformis can be injured, and the sciatic nerve can become compressed, when the hip joint undergoes intorsion, extorsion, or abduction. （3） The structures between the infrapiriform and suprapiriform foramen are where ＂the first threshold＂ sciatic nerve projects. The structures between the infrapiriform and suprapiriform gap were ＂the second threshold＂. This became the concept of ＂double threshold＂. The reduced area caused by pathological changes of ＂double threshold＂ may block and compress the sciatic nerve. Because the common peroneal nerve lies on the anterolateral side of the sciatic nerve, injury to the common peroneal nerve is more serious. CONCLUSION： Anatomical characteristics of the common peroneal nerve, as well as variation of the sciatic nerve, piriformis, and the reduced ＂double threshold＂, are the main causes of sciatic nerve injury, and are especially common in peroneal nerve injury.