Treatment of FBSS Low Back Pain with a Novel Percutaneous DRG Wireless Stimulator: Pilot and Feasibility Study.

OBJECTIVES: Test a miniaturized neurostimulator transforaminally placed at the dorsal root ganglion (DRG) and evaluate the device's safety and efficacy in treating failed back surgery syndrome (FBSS) low back pain. DESIGN: Pilot, two-phase study. SUBJECTS: Eleven subjects with chronic intractable neuropathic trunk and/or lower limbs pain were included. METHODS: The system consisted of an implantable, miniaturized stimulator, provided by Stimwave Technologies (Freedom-4) and an external transmitter. Only one stimulator per subject was implanted unilaterally and transforaminally at L1 to L5 levels. During Phase 1 of the study, the stimulators were not anchored. In Phase 2, the stimulators were anchored. Subjects were treated during 45 days after which the stimulator was removed. Pain reduction, implant duration, and stimulator migration were registered. RESULTS: Overall pain reduction was 59.9%, with only one device placed at one location, covering only a portion of the painful areas in the majority of the subjects. In Phase 1, the non-anchored stimulators migrated a mean of 8.80 mm and in Phase 2 a mean of 1.83 mm. Stimulator migration did not correlate with changes in pain relief. Mean time-to-implant duration was 10 minutes and no adverse events were reported during implant, follow-up period, or after explant. CONCLUSIONS: The pain reduction results indicate that the Freedom-4 spinal cord stimulation (SCS) Wireless System is a viable treatment of low back pain through stimulation of the DRG, and better overall pain reduction may be achieved by implanting multiple devices. With short percutaneous implant times and excellent safety profile, this new system may offer health cost savings.

[Indentification of lumbar foramina with percutaneous pins. A cadaveric study]. / Localización de forámenes lumbares con clavos guía en cadáver.

INTRODUCTION: Patients diagnosed with a lumbar disc hernia and nerve root compression, in which conservative treatment failed are candidates for lumbar discectomy. This technique often results in failed spine surgery syndrome which includes different complications such as arachnoiditis, discitis, and sac tears resulting in pain and neurological deficit. This has led to research of minimally invasive surgery in which the medullary canal is not involved and is performed under local anesthesia. In order to perform this technique, the anatomical and radiological identification of the intervertebral foramina is necessary. Kambin's triangle is an anatomical safe place for percutaneous procedures. OBJECTIVES: (1) To identify Kambin's triangle in the cadaver and its anatomical elements. (2) To describe the relationship between cutaneous lines traced on the patient with the anatomic elements in the cadaver by using guide needles. (3) To describe the position of the surgical instruments used in a posterolateral discectomy approach to identify the triangle. METHODS: (1) Dissection through a standard approach to L1-L5 foramina. (2) Observation of the anatomic planes that the guide needle follows. (3) Radiological study of the foramen. (4) Positioning of the surgical instruments on the foramen to establish the size and space. RESULTS: (1) The intervertebral foramina were dissected and the anatomical components of Kambin's triangle were identified, also we compared size of this triangle (10 mm) and compared it with surgical instruments (7 mm). (2) Skin lines were tested as reliable and safe routes to identify foramina. (3) We proved safety of endoscopic surgery instruments by a posterolateral approach. (4) A visual aid was developed for adequate placement of the guide needle through the foramen. CONCLUSIONS: (1) Foramina need to be perfectly identified with image techniques so that the surgical instruments can be placed safely. (2) Skin lines are a safe and reliable guide. (3) The technique is safe if performed through Kambin's triangle.

[Evocative lumbar discography]. / Discografía evocativa lumbar.

UNLABELLED: Even though lumbar discography was described in 1948 by Lind Bloom as a useful diagnostic method to identify ruptures of the anulus fibrosus of the intervertebral disc, it was neglected for many years as an unreliable method. This happened especially after a publication by Holt, who in 1968 reported a 37% false-positive rate in a study done among inmates, with a very irritating contrast medium (hypaque) that was administered intrathecally. OBJECTIVE: To show that lumbar discography is a dynamic and safe method and even more reliable than magnetic resonance imaging to detect intervertebral disc ruptures. MATERIAL AND METHODS: Thirty-three patients with a clinical history of lumbosciatic pain lasting more than 6 months and an MRI-proven diagnosis of herniated disc were studied. Fifty discographies were performed at the L3-4, L4-5, L5-S1 spaces. They were considered as negative: (1) When the contrast had an oval or cotton-ball shape. (2) When the disc admitted 2-2.5 cm of contrast medium without causing any pain. They were considered as positive: When the contrast dye diffused with an irregular pattern. (2) When the administration of the contrast dye was painful. All negative discographies were followed-up for 6 months. RESULTS: Thirty-three patients; 22 males, 11 females; 50 discographies as follows: 5 at L3-4; 27 at L4-5; and 18 at L5-S1. Five discographies were negative, At six months, the patients were asymptomatic. The discography detected 5 patients, equivalent to a 10% false/positive rate for the magnetic resonance imaging. Two patients developed diskitis. CONCLUSIONS: Discography is more effective than magnetic resonance imaging for detecting intervertebral disc ruptures. Patients with diskitis were related with minimally invasive surgery, probably more due to the infectious process than to discography.