Gary Onik

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.

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.

Percutaneous automated discectomy. A new approach to lumbar surgery.

An automated technique for percutaneous lumbar discectomy applies the principle of suction cutting. The indications are leg pain greater than back pain (sciatica) and failure of all conservative therapy. The typical neurological and roentgenographic abnormalities of a contained herniated lumbar disc are mandatory. The procedure is performed with a Nucleotome (Surgical Dynamics, San Leandro, California) that is a specially designed, 2-mm blunt-tipped suction-cutting device inserted via a posterolateral approach into the affected disc using fluoroscopic control. The results that can be expected with the technique are similar to chymopapain and are in the 70% success range. Automated percutaneous discectomy has a demonstrably low morbidity and can be performed under local anesthesia on an outpatient basis.

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.

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.

Automated Percutaneous Discectomy at the L5-S1 Level: Use of a Curved Cannula

Previously, a major limitation to percutaneous disc decompression to relieve symptoms of sciatica was the inability to approach the L5-S1 level. Obstruction by the iliac crest prevented the instrumentation from entering the L5-S1 disc space. In this paper, the authors describe a curved cannula which can be placed down to the L5-S1 disc space over a straight trocar that has been anchored at the annulus. The cannula bends the flexible aspiration probe back into the plane of the disc so that it is no longer obstructed by the sacral end plate. Using this system, the L5-S1 disc space was successfully removed in 90% of 30 cases.

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.

Automated Percutaneous Discectomy: Preliminary Experience

In 1985, Onik, described a new automated lumbar disc aspiration technique that utilizes a probe with the guillotine cutting technology used in vitrectomy and arthroscopic instrumentation. The probes small size (2 mm in diameter) minimizes the risk of nerve injury, while its automated action permits rapid, safe removal of disc material. The technique and our preliminary results in patients treated with this method are described.

Use of a biplane transrectal ultrasound probe in hepatic cryosurgery: Technical note

The success of hepatic cryosurgery is related to the visualization of the lesions and the monitoring of both the cryoprobe placement and the actual freezing procedures. This article describes the importance of a biplanar trans-rectal ultrasound probe in accomplishing these three things. After visualizing the liver with three different ultrasound probes (3.5 MHz convex, 5.0 MHz convex, and 5.0 linear array), the transrectal ultrasound probe is used. The two transducers in this probe provide a unique view of the liver. More importantly, the transrectal ultrasound probe provides the best imaging for placing the cryoprobes and monitoring the freezing process.

Percutaneous Automated Diskectomy in Athletes

In brief: Six athletes underwent percutaneous automated diskectomy-a new technique for aspirating lumbar disks. The patients had herniated lumbar disks (confirmed by computed tomography and magnetic resonance imaging scans, and/or myelography). Conservative therapy had failed, and they were unable to participate in their respective sports. The procedure, which requires local anesthesia and takes about 45 minutes, was successful in all six cases. No serious complications resulted, and the athletes returned to their sport and functioned normally within six months. Thus, percutaneous automated diskectomy seems to be a reasonable treatment alternative for athletes with herniated lumbar disks without fragmentation into the spinal canal.