Osteophyte at the sacroiliac joint as a cause of sciatica: A report of four cases

Journal of Orthopaedic Surgery, Jun 2002 by Kumar, Bhaskaranand, Sriram, K G, George, Chacko

ABSTRACT

Four cases of sciatica due to osteophytes impinging on the sciatic nerve at the sacroiliac joint are reported. Of these 4 cases, 2 were treated conservatively and the other 2 required surgical excision of the osteophyte. The report highlights the importance of keeping this uncommon etiology in the differential diagnosis of sciatica.

Key Words:sciatica, extraspinal, osteophyte

INTRODUCTION

Sciatica is a common and often disabling symptom of varied etiology. Lumbar disc prolapse is responsible for a majority of cases presenting with sciatica. This fact often overshadows any other lesion causing mechanical nerve root compression that may be closely related to the pathogenesis of sciatica. Thus on most occasions, sciatica gets attributed to intraspinal pathologies to the exclusion of extraspinal pathologies. We are reporting 4 cases of sciatica caused by impingement of the sciatic nerve at the sacroiliac joint by osteophytes. To the best of our knowledge, only one such case has been reported.2

CASE REPORTS

Case 1

A 41-year-old housewife presented with low back pain radiating to the right lower limb of 1 year duration. The pain was insidious in onset, progressive and pricking type. It was unaffected by coughing and sneezing and unrelieved by rest. Examination of the spine showed obliteration of lumbar lordosis and presence of paraspinal muscle spasm. There was no spinal tenderness. On the right side, straight leg raising was restricted to 50 with Grade 3 power in the extensors of the toe and sensory blunting in LS dermatome.

Radiographs of the lumbar spine and pelvis showed early spondylotic changes. The patient was treated conservatively for intervertebral disc prolapse but showed no signs of improvement after 2 weeks. A myelogram was then performed, which was normal. This led us to explore the possibility of an alternative diagnosis. On further clinical examination tenderness was elicited at the right sciatic notch. A critical examination of the radiograph revealed a large osteophyte at the inferior margin of the right sacroiliac joint.

A local injection of 1 ml of 1 % xylocaine at the site of maximum tenderness was given. The patient was relieved of her symptoms immediately. However, the pain recurred with the same intensity after 2 weeks. A decision was then taken to surgically excise the osteophyte. The sciatic nerve was exposed through the Moore's approach. Intraoperatively a swollen and congested sciatic nerve was being impinged by a large osteophyte at the inferior border of right sacroiliac joint. Excision of the osteophyte relieved the patient of her symptoms and she was asymptomatic for the last eight years.

Case 2

A 52-year-old housewife was referred to us for evaluation of pain in the right buttock and lower extremity of 2 years duration. The pain worsened on standing for long hours and was unrelieved by rest. On examination, there was no evidence of paraspinal muscle spasm. There was tenderness at the level of the right sciatic notch. Neurological examination was normal. There was a positive straight leg-raising test at 40 deg on the right side. Radiographs of the lumbar spine and pelvis revealed a large osteophyte at the inferior border of the right sacroiliac joint. She was relieved of her symptoms with a local injection of 1 ml of 1 % xylocaine and 2m1 of 1 % dexamethasone at the site of maximum tenderness. Patient is now asymptomatic for the last three years.

Case 3

A 47-year-old bank employee was referred to us for persistent pain in the left lower buttock and thigh of 3 years duration. He had mild parasthesia in the left posterior thigh and gluteal fold. A physician treated him by means of bed rest, traction and analgesics, but to no avail. Examination revealed tenderness on palpation in the left sciatic notch. Neurological examination was normal, deep tendon reflexes were Grade 2 on the left side. Straight leg-raising on the left at 50 deg caused pain in the left gluteal region and upper posterior thigh. Radiographs of the lumbar spine and pelvis revealed an osteophyte at the inferior border of left sacroiliac joint. A local injection of xylocaine with a steroid at the site of maximum tenderness was given which relieved the patient of his symptoms immediately. The patient has been in our follow up for the last two years without any recurrence of symptoms.

Case 4

A 53-year-old teacher came to us with a one year history of right sided sciatic pain radiating to the posterolateral aspect of the leg and foot. She had been treated conservatively for lumbar disc herniation without any improvement.

There was no paraspinal muscle spasm or tenderness in the lumbar spine. Palpation elicited point tenderness at the right sciatic notch and reproduced the pain in the leg and foot. Straight leg-raising was limited to 40 deg and the Achilles reflex was absent on the right side. In addition, the patient had diminished sensation in the region of S1 dermatome on the right side. Radiographs revealed an osteophyte at the inferior margin of right sacroiliac joint. She was given local injection of xylocaine with a steroid which relieved her of symptoms immediately but the pain recurred with the same intensity within one week. Surgical excision of the osteophyte relieved the patient of her symptoms completely and she continues to be asymptomatic for the last year.