CT body stereotaxic system for placement of needle arrays.

A new CT body stereotaxic system that is particularly suited to multiple placements of needles precisely in parallel is described. By scanning through a right triangle placed on the patient's skin, the stereotaxic method defines an entry point for the first needle placement. An articulating arm is then used to aim the needle at the entry point and hold the needle at the correct angle. The arm can be angled so that the complex approaches from one scan plane to another can be made to place needle arrays through inaccessible lesions, for instance, beneath the diaphragm. Animal and phantom studies have shown that placement of multiple needle arrays in parallel from CT scan data is possible.

CT body stereotaxic instrument for percutaneous biopsy and other interventive procedures: phantom studies.

This article describes a new body stereotaxic system that defines a fiducial point by means of a skin localization device placed directly on the patient. The system uses a rectilinear stereotaxic frame to guide the needles along the calculated path. A method for calculating paths that require angulations from one scan slice to another is described, as well. The system was tested in a foam phantom and shown to be intrinsically accurate in vitro to within 2 mm in both the x and y axis.

Prospective comparison of preoperative imaging and intraoperative ultrasonography in the detection of liver tumors.

A prospective evaluation of the accuracy of preoperative computed tomography (CT), ultrasonography (US), and angiography was performed in 54 patients undergoing resection of hepatic neoplasms. The results were compared with surgical findings and intraoperative ultrasonography (IOUS). A total of 167 lesions was seen by means of IOUS, of which preoperative US enabled detection of 127 (76%). In 48 patients CT allowed detection of 91 of 150 lesions (61%), and in 35 patients angiography showed 56 of 107 lesions (52%). When the detection rate is analyzed according to hepatic segment, the greater overall accuracy of preoperative US may be attributed to a markedly better detection rate in lateral segment of the left lobe of the liver. Lesion size also represented a factor, with preoperative US allowing detection of a greater number of small (less than 2 cm) lesions compared with CT. In patients studied with both CT and US, the combined lesion-detection rate increased to 81% in the right lobe and 76% in the left lobe. Because of this we recommend that preoperative assessment include both CT and US evaluation of the liver. IOUS showed 25% to 35% additional lesions compared with preoperative US and CT. More importantly, 40% of the lesions demonstrated by IOUS were neither visible nor palpable at surgery. We recommend that IOUS be considered in all patients in whom resection of hepatic neoplasm is planned.

Hepatic cryosurgery with intraoperative ultrasound monitoring for metastatic colon carcinoma.

We utilized cryosurgery with intraoperative ultrasound (IOUS) monitoring in ten patients to treat multiple unresectable hepatic metastases from colorectal carcinoma. The liver was exposed at laparotomy, and tumors were subjected to three cycles of freezing (eight minutes each) and thawing. Freezing was monitored by IOUS, which visualized frozen tumor as a hyperechoic rim with posterior acoustic shadowing. Frozen normal liver appeared hypoechoic after thawing compared with normal unfrozen liver. There were no significant complications. The follow-up ranged from four months to 17 months (median, 7.5 months). Tumor response was documented by pathologic findings (coagulative necrosis), progressive fall of carcinoembryonic antigen levels, and computed tomographic scan evidence of necrosis and shrinkage of tumor. One patient underwent repeated laparotomy five months after cryosurgery and had the frozen lesions resected; there was no residual tumor. This study establishes the technical feasibility and antitumor response of hepatic cryosurgery and the use of IOUS for precise localization and monitoring of cryoablations.

Percutaneous transperineal prostate cryosurgery using transrectal ultrasound guidance: animal model.

Cryosurgery has previously been used successfully to treat prostatic carcinoma. Inability to monitor the freezing led to local complications that limited the use of this modality. Recent studies have shown that monitoring of the freezing process can be accomplished using real-time ultrasound. In this study, transrectal ultrasound guidance was used to guide a cryoprobe percutaneously, using a transperineal approach, into the prostate. The extent of freezing was then monitored using ultrasound, taking care not to freeze the urethra or the rectum. Six dogs had the procedure without any complications. This study demonstrates the feasibility of a noninvasive treatment for prostatic carcinoma.

Effect of thermal variables on frozen human primary prostatic adenocarcinoma cells.

OBJECTIVES: Recent advances in imaging technology and cryotechnology have rekindled interest in prostate cryosurgery. Cryosurgery, however, cannot be applied precisely without knowing how the thermal variables used during the procedure affect tissue destruction. The goal of this article is to provide quantitative values for the relationship between thermal variables during freezing and the destruction of human primary prostatic adenocarcinoma cells. METHODS: Human primary prostatic adenocarcinoma cells were frozen with controlled thermal parameters, using a directional solidification apparatus. Cell viability was determined after thawing, using trypan blue and a two-dye fluorescent test and correlated to the thermal variables used during freezing. RESULTS: Human primary prostatic adenocarcinoma cells are damaged by intracellular chemical damage when frozen with cooling rates lower than 5 degrees C/min and by intracellular ice formation when frozen with cooling rates higher than 25 degrees C/min. A double freeze/thaw cycle is required to ensure complete cell destruction at high subzero temperatures, which must be lower than -40 degrees C for the low cooling rates and lower than -19 degrees C for the higher cooling rate. CONCLUSIONS: Haphazard freezing does not necessarily destroy tissue during cryosurgery; however, quantitative data on the relation between thermal variables and frozen cell destruction can provide the means for performing cryosurgery more precisely and with greater control over the outcome of the procedure.

Ultrasound characteristics of renal cryosurgery.

The ability to visualize renal cryosurgery using ultrasound was tested in an animal model. Five dogs underwent open laparotomy and ultrasound-monitored cryosurgery of both kidneys. On each kidney two cryolesions were made. The borders of the frozen region were identified on ultrasound as a hyperechoic rim created by the interface between frozen and unfrozen tissue. The thawed cryolesion appeared hyperechoic compared with the unfrozen kidney. Excellent correlation between the ultrasound and autopsy measurements of the cryolesions was obtained. Knowing this, renal cryosurgery under ultrasound monitoring may be possible.

Far-lateral disk herniation: treatment by automated percutaneous diskectomy.

Automated percutaneous diskectomy has certain advantages over other surgical approaches to the treatment of far-lateral disk herniation; primarily, the procedure can be performed under local anesthesia without soft-tissue disruption. We describe four patients with far-lateral herniations who were successfully treated with the procedure.

Nuances in percutaneous discectomy.

This article presents an update of the field of percutaneous discectomy and a perspective as to where percutaneous discectomy currently fits in the treatment of patients with herniated discs. The future of minimally invasive disc surgery is also entertained, and a novel approach to lumbar disc surgery is presented.

Cauda equina syndrome secondary to an improperly placed nucleotome probe.

Automated percutaneous lumbar discectomy has been shown to be a low morbidity procedure in the treatment of contained herniated lumbar discs. Described in this paper is a complication, i.e., a cauda equina syndrome secondary to a Nucleotome probe improperly placed in the thecal sac. The authors reemphasize the landmarks for the thecal sac, i.e., the medial border of the pedicles, and discuss the preventable nature of this type of complication.

Mechanical aspiration of hematomas in an in vitro model.

A modified Nucleotome (Surgical Dynamics, San Leandro, California) was used to aspirate blood clot in an in vitro model of intracerebral hematoma. This machine was successful in removing the clot at a reasonably rapid rate. It aspirates normal rat brain far more slowly. It therefore shows promise for being effective and safe in removing intracerebral hematomas in humans.

Percutaneous automated biopsy in the diagnosis of primary infectious spondylitis.

Three cases of primary infectious spondylitis, two caused by Staphylococcus aureus and one by tuberculosis, were diagnosed using the method previously described for automated percutaneous discectomy. All three patients, in whom biopsy using fine needle techniques previously was unsuccessful, had positive cultures from specimens obtained using the automated method. The method combines the advantages of local anesthesia and minimal morbidity with the obtaining of adequate material for culture and pathological examination.

Automated percutaneous discectomy: a prospective multi-institutional study.

A prospective multi-institutional study was carried out to evaluate automated percutaneous discectomy in the treatment of lumbar disc herniations. Of the 327 patients who prospectively met the study criteria and were followed for longer than 1 year, 75.2% were successfully treated. When patients (n = 168) who prospectively did not meet the study criteria were treated, the success rate was 49.4%. One case of discitis was reported; otherwise, no other serious complications were noted, and specifically no vascular or nerve damage was encountered. This study indicates that automated percutaneous discectomy can be used successfully to treat lumbar disc herniations with minimal morbidity and emphasizes the need for proper patient selection.

Percutaneous automated discectomy: a new method for lumbar disc removal. Technical note.

A new technique for percutaneous lumbar disc removal is described. The specially designed 2-mm blunt-tipped suction/cutting probe (nucleotome) is similar to the automated vitrectomy instrumentation used by ophthalmic surgeons. The procedure is performed under local anesthesia, with the patient in the prone position and with fluoroscopic guidance. The nucleotome is inserted into the appropriate disc space with specially designed instrumentation, guided by landmarks similar to those used in needle placement for chemonucleolysis. The technique has been evaluated in 20 patients with herniated discs (one at the L3-4 level and 19 at the L4-5 level) confirmed by myelography and/or computerized tomography scans after all conservative therapy for primarily radicular pain had failed. From 1 to 7 gm of disc material was removed in an average total operative time of approximately 1 hour. Eighty percent of the patients had good to excellent results in a short-term follow-up period of 6 months. Four patients subsequently required standard surgical excision of free disc fragments. No significant complications occurred. The procedure is contraindicated in patients with extruded or free fragments of disc in the spinal canal or in patients with herniations at the L5-S1 level pending development of additional instrumentation for insertion at that level. More extensive long-term studies are needed to further evaluate this procedure.

Cryosurgery re-visited for the removal and destruction of brain, spinal and orbital tumours.

Advances in neuroimaging and cryosurgical techniques have prompted us to re-evaluate the potential of cryosurgical techniques for the removal and the destruction of various neoplasms. We have used cryosurgical instrumentation to remove tumours in the brain, spine and orbit in 71 patients without complications. Cryosurgery was used to facilitate removal and extraction in 64 and to destroy residual neoplasms when removal was incomplete in 7. Intraoperative real time ultrasonic imaging permitted precise delimitation of tumours from surrounding tissues and allowed monitoring during the production of cryosurgical lesions thus permitting heretofore unavailable visualization of the production of cryogenic lesions in the central nervous system. New cryosurgical instrumentation was used to produce lesions up to three times larger than similar sized probes previously available. Our results reconfirm that cryosurgery facilitates the removal of tumours in the brain, spinal cord and orbit, reduces blood loss in vascular tumours, and is effective in ablating residual neoplasms involving the superior sagittal sinus, torcula and parasagittal areas. A Doppler flowmeter proved useful for monitoring sagittal sinus blood flow during the production of cryosurgical ablation of residual tumour attached to the walls of the sagittal sinus. Recent advances in ultrasonic and neuroimaging coupled with stereotactic techniques and improvements in cryosurgical instrumentation may prove useful in the future percutaneous destruction of selective intracranial neoplasms.

Automated percutaneous lumbar diskectomy.

Automated percutaneous lumbar diskectomy was introduced in 1985. Development of this technique was instigated by the general trend in medicine toward less invasive procedures. Technique, indications, patient selection, and a review of the current literature are presented. Cumulative data indicate that the procedure has the least potential to do harm compared to open operations for treating lumbar disk herniations.

Automated percutaneous discectomy.

Automated percutaneous discectomy is a new, safe procedure for treating herniated lumbar discs still contained by the annulus or posterior longitudinal ligament. In 1985, one of the authors reported a percutaneous nucleus aspiration technique using a 2-mm aspiration probe. This small probe produced minimal tissue damage, allowing the procedure to be done on an outpatient. In this series, 518 patients were treated using this technique for an overall success rate of 85%. Compensation patients, elderly patients, and patients with previous surgery were treated successfully using percutaneous discectomy on an outpatient basis. No intraoperative or postoperative complications occurred.

Minimally invasive disc surgery. Nucleotomy versus fragmentectomy.

There is continued debate as to the optimum surgical management of a herniated disc with sciatica. There are proponents of conventional microdiscectomy as well as those who advocate minimally invasive approaches, including central disc decompression or nucleotomy as well as arthroscopic lumbar microdiscectomy and fragmentectomy. In this controversy (I), Dr. Gary Onik takes the position that central disc decompression is both safe and efficacious and may be the procedure of choice for recurrent disc herniations (II). Dr. Parvis Kambin takes the opposing position and advocates arthroscopically assisted fragmentectomy as the procedure of choice.

Percutaneous diskectomy in the treatment of herniated lumbar disks.

APLD and the minimally invasive approach to spine surgery has stood the test of time successfully. With the advent of new imaging technologies to aid in the guidance of spine procedures, such as three-dimensional ultrasound, interventional MR imaging, and fluoroscopic CT, and the development of flexible instruments that can be navigated within the disk, the stage is now set for major breakthroughs in the treatment of herniated lumbar disks (i.e., the minimally invasive removal of extruded and free disk fragments). With the active role of radiologists and sophisticated imaging, minimally invasive spinal intervention has a bright and exciting future.

Automated percutaneous biopsy in the diagnosis and treatment of infectious discitis.

The author's experience using automated disc aspiration for the diagnosis of discitis indicates that skinny needle aspiration biopsy has a very high false-negative rate. A negative skinny-needle biopsy, therefore, must be followed by a procedure to obtain a better sample of pathologic material. Automated disc aspiration, because of its safety and ability to provide a large specimen, is the procedure of choice. Attention, however, must be paid to technical details of the procedure and the poor annular integrity of the infected disc to carry out the procedure safely.