Technology improvements for image-guided and minimally invasive spine procedures.

This paper reports on technology developments aimed at improving the state of the art for image-guided minimally invasive spine procedures. Back pain is a major health problem with serious economic consequences. Minimally invasive procedures to treat back pain are rapidly growing in popularity due to improvements in technique and the substantially reduced trauma to the patient versus open spinal surgery. Image guidance is an enabling technology for minimally invasive procedures, but technical problems remain that may limit the wider applicability of these techniques. The paper begins with a discussion of low back pain and the potential shortcomings of open back surgery. The advantages of minimally invasive procedures are enumerated, followed by a list of technical problems that must be overcome to enable the more widespread dissemination of these techniques. The technical problems include improved intraoperative imaging, fusion of images from multiple modalities, the visualization of oblique paths, percutaneous spine tracking, mechanical instrument guidance, and software architectures for technology integration. Technical developments to address some of these problems are discussed next. The discussion includes intraoperative computerized tomography (CT) imaging, magnetic resonance imaging (MRI)/CT image registration, three-dimensional (3-D) visualization, optical localization, and robotics for percutaneous instrument placement. Finally, the paper concludes by presenting several representative clinical applications: biopsy, vertebroplasty, nerve and facet blocks, and shunt placement. The program presented here is a first step to developing the physician-assist systems of the future, which will incorporate visualization, tracking, and robotics to enable the precision placement and manipulation of instruments with minimal trauma to the patient.

MRI-guided frameless stereotactic percutaneous cordotomy.

BACKGROUND: Use of intraoperative myelography as a radiologic guidance for percutaneous cervical cordotomy (PCC) has been superseded by more modern imaging. The only significant advancement in cordotomy techniques over the last 30 years has been CT-guided PCC. The goal of this study was to demonstrate the feasibility of an MRI-guided frameless technique in high cervical cordotomy. METHODS: We describe 6 patients with intractable pain treated using a frameless, MRI-guided, stereotactic, PCC technique in combination with standard physiological localization procedures. Results were compared with those from 32 patients who underwent PCC in the last 5 years using physiological localizing techniques only. RESULTS: Six patients (100%) who underwent the frameless technique had excellent pain relief postoperatively. Patients in the non-stereotactic group, on average, required a higher number of lesions (2.5 vs. 1.2, p < 0.005), and 7 (22%) of these patients had unsatisfactory pain relief following PCC (p = 0.21). Five patients in the non-stereotactic group had weakness postoperatively and 1 had changes in bladder function. Postoperative weakness occurred in 1 patient undergoing the frameless technique. At an average of 6 months of follow-up (range 5-11), excellent pain relief was achieved in 83% (5/6) of MRI frameless PCC patients and 55% (16/29) of standard PCC patients (p = 0.20). CONCLUSIONS: Intraoperative frameless stereotaxy provides surgeons with accurate information that helps to guide the operative approach and precisely tailor the trajectory and depth of the electrode, potentially increasing the safety and efficacy of the operation.

CT-guided percutaneous punctate midline myelotomy for the treatment of intractable visceral pain: a technical note.

Surgical treatment of intractable visceral pain has always been a challenge. The relatively recent discovery of a specific visceral pain pathway brought a new insight to this matter. The authors describe a new technique to interrupt this pathway, the CT-guided percutaneous punctate midline myelotomy, successfully applied in two patients with intractable pelvic visceral pain. Due to its simplicity, safety and high effectiveness, it may become the treatment of choice for intractable visceral pain.

Radiofrequency treatment of trigeminal neuralgia using a cordotomy-type electrode. A method.

A specific technique for treating trigeminal neuralgia with radiofrequency thermocoagulation uses a small electrode which allows the lesion to be made behind the ganglion in the retro gasserian rootlets where little pain is produced and the patient can be treated while awake. On-line monitoring during the lesioning with this electrode permits accurate control over the location and extent of the numbness in the face. This technique yields a very high incidence of patient satisfaction and a very low incidence of annoying dysesthesias in the face and corneal sensory loss.

CT-guided percutaneous selective cordotomy.

In this article the technique of CT-Guided Selective Cordotomy is described. The advantages of CT guidance in percutaneous cordotomy are the measurement of spinal cord diameters at the lesion site for each individual patient, direct visualization of target electrode relations, demonstration of spinal cord displacement during the procedure and localization of the electrode system in a specific part of the spinothalamic tract. Local destruction of the spinothalamic tract leads to selective cordotomy. Since 1987, CT-Guided Cordotomy has been applied to 54 cases of intractable cancer pain. In 33 of the 54 cases, the cordotomy was selective enough to be successful with a local denervation of the area where the pain was dominant. Except for one temporary hemiparesis and one temporary ataxia, no complications or side effects were observed.

[A new apparatus and stereotactic method for percutaneous high cervical cordotomy].

The authors devised a stereotactic apparatus for percutaneous cordotomy based on the experience of 191 percutaneous high cervical cordotomies on 150 patients suffering from intractable pain. This apparatus has two major components. One is a head and neck holder and the other is a guide and marker system. The head and neck holder contains fixed neck holder and head holder which can be movable in vertical direction. Using these holders, the operator can keep the patient's neck in neutral position. The marker system contains two markers of origin and a 10mm scale which indicates center line as well. The guide system, stereotactically designed, is movable in three direction and acrylic guide groove is attached. The guide needle for percutaneous cordotomy is inserted along the guide groove. The guide and marker system can be attached in both sides of the head and neck holder, therefore, the operator can insert the needle in both sides of the patient. This apparatus makes it possible to locate the target stereotactically for percutaneous cordotomy, since location of the inserted needle can be determined with the aid of cervical X-ray, even if there is no image intensifier of TV display screen available. Therefore it can be possible to reduce the X-ray exposure of the patient.

Somatotopic arrangement of lateral spinothalamic tract in percutaneous cervical cordotomy.

As a new clinical approach for the purpose of mapping a lamina analysis, the present report deals with another landmark for insertion of the spinal needle in man other than the usual dentate ligament when performing a percutaneous cordotomy. Electrophysiological studies were made on 19 patients in order to determine the effect of electrostimulation with a bipolar concentric electrode, as well as to corroborate the position of the electrode radiologically. A new apparatus has been devised so that one can locate the target insertion point easily.

[Percutaneous chordotomy with radiofrequency: results in 62 surgical cases]. / Cordotomia percutânea com radiofrequência: resultados em 62 casos operados.

The results obtained in sixty two patients treated by percutaneous cordotomy are reported. The technique used is described with the following results: excellent in 79%, regular in 11.5% and negative in 9.5% of the cases. Negligible complications are reported. The author concludes as others have previously shown that the advantages of this procedure are due to its simplicity and easiness to perform. Otherwise it can be employed in the very sick, such as cancer patients. The author points out to the importance of percutaneous cordotomy in cases where pain is a limiting factor to a more functional life, rather the widespread use of narcotics.