Computer-tomographic verification of ultrasound-guided piriformis muscle injection: a feasibility study.

BACKGROUND: Approximately 6% to 8% of lumbar pain cases, whether associated with radicular pain or not, may be attributed to the presence of piriformis muscle syndrome. Available treatments, among others, include pharmacotherapy, physical therapy, and injections of different substances into the muscle. Various methods have been used to confirm correct needle placement during these procedures, including electromyography (EMG), fluoroscopy, computed tomography (CT), or magnetic resonance imaging (MRI). Ultrasonography (US) has now become a widely used technique and therefore may be an attractive alternative for needle guidance when injecting this muscle. OBJECTIVE: The objective of this study was to assess the reliability of US in piriformis injection of patients with piriformis syndrome. STUDY DESIGN: Feasibility study; 10 patients with piriformis muscle syndrome were injected with botulinum toxin A using a US-guided procedure. Then patients were administered 2 mL iodinated contrast and were then transferred to the CT scanner, where they underwent pelvic and hip imaging to assess intramuscular distribution of the iodinated contrast. SETTING: Multidisciplinary Pain Management Department in Spain. RESULTS: Of all 10 study patients (8 women, 2 men), 9 had intramuscular or intrafascial contrast distribution. Distribution did not go deeper than the piriformis muscle in any of the patients. The absence of contrast (intravascular injection) was not observed in any case. LIMITATIONS: The main limitation of our study is the use of ionizing radiation as confirmation technique. CONCLUSION: Ultrasound-guided puncture may be a reliable and simple procedure for injection of the piriformis muscle, as long as good education and training are provided to the operator. US has a number of advantages over traditional approaches, including accessibility and especially no ionizing radiation exposure for both health care providers and patients.

Radioisotope cisternography: a potentially useful tool for headache diagnosis in patients with an IDD pump.

BACKGROUND: Spontaneous intracranial hypotension (SIH) and related headache after intrathecal pump implantation is a possibility. Knowing the exact location of the cerebrospinal fluid (CSF) leak is mandatory for managing with interventional therapies. OBJECTIVES: Radioisotope cisternography (RICG) is a common procedure in nuclear medicine and may be used as an additional procedure in the differential diagnosis of headaches due to intracranial liquor hypotension syndrome caused by microleakage of CSF. STUDY DESIGN: We report an imaging case of complex chronic headache in a patient with an implanted drug delivery pump. The symptomatology of the patient was considered typical of spontaneous intracranial hypotension (SIH). Therefore, the initial suspicion was the loss of CSF due to the implanted pump catheter. The negativity of the routine headache test can exclude any leakage of CSF at the site of catheter insertion. SETTING: Anesthesia, Critical Care, and Multidisciplinary Pain Management Department, General University General Hospital, Valencia, Spain. RESULTS: Many patients are treated with implanted intrathecal infusion systems. In these patients, any neurological symptoms are readily attributed to the invasive neuroaxial system, especially severe cephalalgia. RICG was helpful in this particular case to make a diagnosis of exclusion of the diagnosis of SIH due to CSF leakage. CONCLUSION: RICG may be considered as an additional diagnostic technique in patients with chronic pain and implanted spinal infusion devices for whom standard detection procedures have been exhausted.

Role of lumbosacral retrograde neuromodulation in the treatment of painful disorders.

BACKGROUND: Neuromodulation is an effective and reversible treatment option for chronic intractable pain. Spinal cord stimulation (SCS) represents a field of application of neuromodulation and is known to be effective for several conditions including complex regional pain syndrome (CRPS), failed back surgery syndrome (FBSS), and chronic leg and back pain. SCS has some technical limitations that can be bypassed through retrograde neuromodulation. OBJECTIVE: To examine the safety and efficacy of retrograde neuromodulation in consecutive patients with neuropathic pain in the perineum or lower limb. STUDY DESIGN: Prospective chart review analyzing one year of retrograde stimulation in our department. METHODS: We present a series of 10 patients who underwent retrograde neuromodulation at the University General Hospital of Valencia (Spain). We analyzed the variables that can improve the outcome and help physicians choose retrograde neuromodulation. RESULTS: Seven of 10 patients had an effective treatment and 3 patients had an ineffective stimulation. In the group with the effective treatment the most represented type of pain was radiculopathy and perineal pain. LIMITATIONS: This is a prospective, single-center study with a relatively small number of patients and no control group. CONCLUSION: Retrograde neuromodulation seems to be effective in patients that present with a well localized pain with a clear dermatome distribution. We found retrograde neuromodulation to be effective in radiculopathy related to FBSS. We found it to be limited in the treatment of perineal pain probably due to technical limitations and anatomical reasons besides the lack of knowledge of the etiology of this pain model and the exact mechanisms of action of neuromodulation.