Sciatica of non-disk origin and piriformis syndrome: diagnosis by MR neurography and interventional MRI with outcome study of resulting treatment

Cedars-Sinai Medical Center, Los Ángeles, California, United States
Journal of Neurosurgery Spine (Impact Factor: 2.38). 03/2005; 2(2):99-115. DOI: 10.3171/spi.2005.2.2.0099
Source: PubMed


Because lumbar magnetic resonance (MR) imaging fails to identify a treatable cause of chronic sciatica in nearly 1 million patients annually, the authors conducted MR neurography and interventional MR imaging in 239 consecutive patients with sciatica in whom standard diagnosis and treatment failed to effect improvement.
After performing MR neurography and interventional MR imaging, the final rediagnoses included the following: piriformis syndrome (67.8%), distal foraminal nerve root entrapment (6%), ischial tunnel syndrome (4.7%), discogenic pain with referred leg pain (3.4%), pudendal nerve entrapment with referred pain (3%), distal sciatic entrapment (2.1%), sciatic tumor (1.7%), lumbosacral plexus entrapment (1.3%), unappreciated lateral disc herniation (1.3%), nerve root injury due to spinal surgery (1.3%), inadequate spinal nerve root decompression (0.8%), lumbar stenosis (0.8%), sacroiliac joint inflammation (0.8%), lumbosacral plexus tumor (0.4%), sacral fracture (0.4%), and no diagnosis (4.2%). Open MR-guided Marcaine injection into the piriformis muscle produced the following results: no response (15.7%), relief of greater than 8 months (14.9%), relief lasting 2 to 4 months with continuing relief after second injection (7.5%), relief for 2 to 4 months with subsequent recurrence (36.6%), and relief for 1 to 14 days with full recurrence (25.4%). Piriformis surgery (62 operations; 3-cm incision, transgluteal approach, 55% outpatient; 40% with local or epidural anesthesia) resulted in excellent outcome in 58.5%, good outcome in 22.6%, limited benefit in 13.2%, no benefit in 3.8%, and worsened symptoms in 1.9%.
This Class A quality evaluation of MR neurography's diagnostic efficacy revealed that piriformis muscle asymmetry and sciatic nerve hyperintensity at the sciatic notch exhibited a 93% specificity and 64% sensitivity in distinguishing patients with piriformis syndrome from those without who had similar symptoms (p < 0.01). Evaluation of the nerve beyond the proximal foramen provided eight additional diagnostic categories affecting 96% of these patients. More than 80% of the population good or excellent functional outcome was achieved.

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    • "Management often poses a problem to clinicians especially if the reason for the pain cannot be identified with great certainty. The independent point prevalence of sciatica in the adult population is greater than 5% and its lifetime prevalence is as high as 40% [2]. The concept of sciatica remains unclear and imprecise, mixing true radicular pain with ordinary lower limb radiating pain. "
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    ABSTRACT: It is commonly accepted that the common cause of acute/chronic pain in the distribution of the lumbosacral nerve roots is the herniation of a lumbar intervertebral disc, unless proven otherwise. The surgical treatment of lumbar disc herniation is successful in radicular pain and prevents or limits neurological damage in the majority of patients. Recurrence of sciatica after a successful disc surgery can be due to many possible etiologies. In the clinical setting we believe that the term sciatica might be associated with inflammation. We report a case of acute sciatic neuritis presented with significant persistent pain shortly after a successful disc surgery. The patient is a 59-year-old female with complaint of newly onset sciatica after complete pain resolution following a successful lumbar laminectomy for acute disc extrusion. In order to manage the patient's newly onset pain, the patient had multiple pain management visits which provided minimum relief. Persistent sciatica and consistent physical examination findings urged us to perform a pelvic MRI to visualize suspected pathology, which revealed right side sciatic neuritis. She responded to the electrical neuromodulation. Review of the literature on sciatic neuritis shows this is the first case report of sciatic neuritis subsequent to lumbar laminectomy.
    Case Reports in Medicine 06/2014; 2014(2):404386. DOI:10.1155/2014/404386
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    • "It could be hypothesized that sciatica patients have different experiences of health care, particularly its psychosocial aspects, because sciatica is associated with definable pathologies, most commonly disc herniation and lumbar spinal stenosis, whereas most cases of LBP are labeled nonspecific. However, some argue that a significant proportion of sciatica is not explained by those pathologies [4], and others dispute that LBP is nonspecific and argue that specific diagnoses can and should be made [5]. "
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    ABSTRACT: Previous systematic reviews of patients' experience of health services have used mixed qualitative and quantitative studies. This review focused on qualitative studies, which are more suitable for capturing experience, using modern methods of synthesis of qualitative studies. To describe the experience of health care of low back pain and sciatica patients and the sources of satisfaction or dis-satisfaction with special reference to patients who do not receive a diagnosis. A systematic review of qualitative studies SAMPLE: Primary qualitative studies identified from MEDLINE, EMBASE, CINAHL and Psychinfo databases. Conceptual themes of patients' experiences. Data collection and analysis was through thematic content analysis. Two reviewers independently screened titles, collected and analysed data. The authors were in receipt of a Primary Care Research Bursary from NHS Suffolk and Norfolk Research Departments, a not-for-profit organization. Twenty eight articles met the inclusion criteria. Most studies were of high quality. Nine themes emerged: the process and content of care; relationships and interpersonal skills; personalised care; information; the outcome of care; the importance of a diagnosis; delegitimation; recognising the expert; and service matters. How care was given mattered greatly to patients, with importance given to receiving a perceived full assessment, consideration for the individual's context, good relationships, empathy and the sharing of information. These aspects of care facilitated the acceptance by some of the limitations of health care and were spread across disciplines. Not having a diagnosis made coping more difficult for some but for others led to delegitimation, a feeling of not being believed. Service matters such as cost and waiting time received little mention. While much research into the development of chronic LBP has focused on the patient, this review suggests that research into aspects of care also warrant research. The benefits of generic principles of care, such as personalisation and communication, are important to patients with LBP and sciatica so practitioners may help their patients by paying as much attention to them as to specific interventions. When neither cure nor a diagnostic label are forthcoming, generic skills remain important for patient satisfaction.
    The spine journal: official journal of the North American Spine Society 04/2014; 14(8). DOI:10.1016/j.spinee.2014.02.029 · 2.43 Impact Factor
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    • "Neurological examination combined with nerve-conduction-studies and EMG is the gold standard in the evaluation of peripheral nerve injuries. Recently MRN has emerged as an additional diagnostic method for the evaluation of peripheral nerve lesions [16], [19]–[25]. MRN is capable to display the peripheral nervous system from the nerve roots, along the plexus to distally located peripheral nerves. With transverse imaging sections, MRN at a magnetic field strength of 3 Tesla is capable of visualizing not only nerve trunks but also the nerve fascicles. "
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    ABSTRACT: Sciatic nerve palsy related to hip replacement surgery (HRS) is among the most common causes of sciatic neuropathies. The sciatic nerve may be injured by various different periprocedural mechanisms. The precise localization and extension of the nerve lesion, the determination of nerve continuity, lesion severity, and fascicular lesion distribution are essential for assessing the potential of spontaneous recovery and thereby avoiding delayed or inappropriate therapy. Adequate therapy is in many cases limited to conservative management, but in certain cases early surgical exploration and release of the nerve is indicated. Nerve-conduction-studies and electromyography are essential in the diagnosis of nerve injuries. In postsurgical nerve injuries, additional diagnostic imaging is important as well, in particular to detect or rule out direct mechanical compromise. Especially in the presence of metallic implants, commonly applied diagnostic imaging tests generally fail to adequately visualize nervous tissue. MRI has been deemed problematic due to implant-related artifacts after HRS. In this study, we describe for the first time the spectrum of imaging findings of Magnetic Resonance neurography (MRN) employing pulse sequences relatively insensitive to susceptibility artifacts (susceptibility insensitive MRN, siMRN) in a series of 9 patients with HRS procedure related sciatic nerve palsy. We were able to determine the localization and fascicular distribution of the sciatic nerve lesion in all 9 patients, which clearly showed on imaging predominant involvement of the peroneal more than the tibial division of the sciatic nerve. In 2 patients siMRN revealed direct mechanical compromise of the nerve by surgical material, and in one of these cases indication for surgical release of the sciatic nerve was based on siMRN. Thus, in selected cases of HRS related neuropathies, especially when surgical exploration of the nerve is considered, siMRN, with its potential to largely overcome implant related artifacts, is a useful diagnostic addition to nerve-conduction-studies and electromyography.
    PLoS ONE 02/2014; 9(2):e89154. DOI:10.1371/journal.pone.0089154 · 3.23 Impact Factor
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