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Nucleotome®

Physician Reference Manual

Automated Percutaneous Lumbar Discectomy

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Nucleotome®

Automated Percutaneous Lumbar Discectomy (APLD)

Table of Contents Section 1

I. Description of Nucleotome System …….…………………………. 3

II. U.S Food and Drug Administration Status ………………………… 5

III. Indications and Contraindications for Nucleotome………………… 6

IV. Patient Outcomes ………………………………………………….. 8

V. Safety ………………………………………………………………. 9

VI. APLD as Compared to Alternative Forms of Treatment ………….. 10

VII. Cost Benefits ………………………………………………………. 12

Reference List……………………………………………………………… 13

Section 2 – Clinical Study Summaries (Full articles are on file with

Clarus Medical and are available upon request)………………….. 14

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I. Description of Nucleotome® System

1. Basic Description of Procedure

Nucleotome is a tradename for Automated Percutaneous Lumbar Discectomy (APLD). APLD is a minimally invasive method for treating patients’ contained disc herniations. The Nucleotome utilizes a mechanical suction and cutting system to decompress nucleus pulposus.

2. Nucleotome Kit Components

A Nucleotome Probe Set may contain the following components and accessories required for APLD.

• NucleotomeProbe - Instrument used to aspirate and shave nucleus pulposus. A seal nut with “O” ring is included on the probe needle, which is used to lock into the cannula when the probe is activated and to provide an airtight seal.

• Marking Pen - Used to mark entry point into the body. • Measuring Scale - Used to assist in marking the correct entry point. • Scalpel - May be used to incise the skin to facilitate easy passage of

components.

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• Guide Needle - Used for initial access inside the disc and ensure correct path of instruments.

• Cannula/Dilator - Passed over Guide Needle to create a working channel.

• Curved Cannula/Dilator – Used in certain anatomy • Trephine - Used to incise the annulus.

3. How Nucleotome Probe Works

Once access is gained to the nucleus of the disc, the Nucleotome probe is inserted through the working channel cannula. The Nucleotome probe tip has a rounded tip with a side port near the distal end. Saline is pneumatically driven through the probe by the Nucleotome Console, which creates a vacuum effect and sucks nuclear material through the side port. As nuclear material is suspended in saline, a reciprocating inner cannula shaves the nucleus at a rate of up to 180 cuts per minute. Nucleus is suctioned through tubing attached to the Nucleotome handle and collected in a filter within an aspiration canister.

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II. U.S. Food and Drug Administration (FDA) Status All Nucleotome products have received FDA clearance. The following is applicable for the models currently being marketed.

510(k) Device Name Decision Date

K844131 Nucleotome 11/29/84

K923525 Nucleotome 3.5 mm Automated Percutaneous Discectomy

2/9/93

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III. Indications and Contraindications for Nucleotome

In order to increase APLD’s success rate in patients, it is recommended that the physician follow the strict indications. APLD is advised for patients with relatively small contained herniations, only after conservative treatment has failed. Chances of success significantly decrease in patients with larger extruded, or fragmented herniations. Following are patient indications and contraindications as listed on Nucleotome’s Directions for Use:

Indications

• Unilateral leg pain greater than back pain. • Paresthetic discomfort in a specific dermatomal distribution. • Positive straight leg raising test and/or positive bowstring sign. • Patient demonstrates possible neurologic findings (wasting, weakness,

sensory alteration, and reflex alteration). • Patient shows no improvement after at least six weeks of conservative

therapy. • A positive CT or MRI that shows a subligamentous herniation at the

location; consistent with clinical finding.

Contraindications • Radiologic evidence of a diffuse annular bulge extending out from the

entire circumference of the vertebral body. • Radiologic evidence of severe lateral recess stenosis, calcified disc

herniations, severe degenerative facet disease and ligmentum flavum hypertrophy.

• Radiologic evidence of free or extruded disc fragments within the spinal canal.

• Clinical evidence of significant progressive neurologic deficits and/or cauda equina syndrome.

• The existence of other pathologies or conditions, such as fracture, tumor, pregnancy or active infection that would put patient at risk.

Up to 80% of the population may complain of at least one episode of low back pain during their active life15. Of these patients, APLD should only be considered for a very small minority, for which the indications are narrowly defined. In 1989, Mooney1 described patient selection in a study that reported a 75% success rate; “Selection of the proper patient for this procedure must be based on the demonstration of a structural abnormality creating nerve root irritation that is potentially reversible by decompression of nuclear material. Thus, if extruded nuclear material can be demonstrated, or if skeletal elements or ligamentum flavum is considered the source of nerve root irritation, decompression of the nucleus internally will be of no benefit. The starting point, therefore, must be based on a clinical evaluation. If the irritated nerve root is the source of the pain, leg pain must be expected as a part of the complaint. Ideally the leg pain is unilateral and more severe than back pain. Central disc herniations can occur, and in these situations

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bilateral leg pain or even back pain alone may be the clinical presentation. CT discography is the only sure way to differentiate symptomatic central herniation from an annular bulge. Ideally the pain should be intermittent and relievable by some posture or change of position. This suggests that nuclear flow is available…”

Numerous published studies with results consistent with Dr. Mooney’s adhere to proper selection criteria.1,2,3,4,5,7 Conversely, in 1993, Revel et al.16 published results of a study comparing APLD versus Chemonucleolysis. Of the 141 patients, 69 were treated with APLD. The rate of success was significantly lower (43%) than most studies. In this study, important labeling instructions were disregarded:

• The requirement of the contained, non-extruded disc for inclusion is not specified in the study protocol: At discography, 39% of the tested discs showed epidural leakage.

• The protocol allowed migration up to 5 mm beyond the disc space and the publication lists 71% of APLD patients in this category. However, the earlier patient data gave an incidence of 29% pf patients with migration of 5 to 10 mm, an apparent violation of the protocol. A concern that some of these cases had large extrusions of free fragments is further reinforced by the following incidences:

- 8% of patients with bilateral leg pain; - 14% with large volume herniations; and - the inclusion of patients with a positive crossed straight leg raising

test. • The protocol or the publication does not specify the exclusion of discs with

diffuse annular bulging for which APLD is not effective and is therefore contraindicated:

- 16% incidence at discography of severely degenerated discs, and - 9% with marked disc space narrowing; tow cases are described as

technical failures after it was impossible to introduce the probe into the disc space.

• There was no requirement that leg pain is greater than back pain for inclusion, although the publication insists that only sciatica patients were included in the study:

- 21% of patients had severe back pain, but no correlation to leg pain was made.

In summary, the reason for lower success rate of patients treated with APLD in the Revel study is improper patient selection. The significant percentages of selection factors listed above, singly or in combination, indicate that patients were included in this study that had extruded herniations, free fragments, or severely degenerated and bulging discs. An unfavorable rate of successful outcome after APLD is expected in patients with disc pathologies which are known to respond only marginally to this treatment, or for which treatment is even contraindicated.

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IV. Patient Outcomes

There have been a large number of high quality studies completed to document the success of Nucleotome. The results are consistent in the vast majority of the studies. Nucleotome has proven to be successful in approximately 75% of cases with properly selected patients. The risk factors for these patients were extremely low. (Please see chart below for reference). In addition, APLD is almost always performed on an outpatient basis, which allows the patient to return to a normal lifestyle more quickly with minimal postoperative pain.

Article Number*

Study Patient Number

Complicaton Rate

SuccessRate

1 Mooney V., Percutaneous Discectomy, Spine: State of the Art Review, Jan 1989: Vol. 3, No. 1: 103-112.

64 0 75%

2 Onik, G., Mooney, V., Maroon J., et al: Automated Percutaneous Discectomy: A Prospective Multi-Institutional Study, Neurosurgery 1990: Vol. 26, No. 2: 228-233

506 .002% 75%

3 Davis G., Onik G., Helms C., Automated Percutaneous Discectomy, Spine 1991: Vol. 16, No. 13: 359-363

518 .002% 85%

4 Gill K., Blumenthal S., Clinical Experience with Automated Percutaneous Discectomy: The Nucleotome System, Orthopedics 1991: 14: 757-760

62 0 79%

5 Teng, et al.: Automated Percutaneous Lumbar Discectomy: A Prospective Multi-institutional Study, Journal of Vascular Interventional Radiology, Vol. 8, No. 3: 457-463

1525 .06% 83%

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V. Safety

Over 200,000 APLD procedures have been performed worldwide. In more than 50 published series, there has been no reported mortality or major nerve injury during a Nucleotome procedure.8 Complication rates are consistently below 1%,1,2,3,4,5,6,7 with the majority of the complications being relatively minor.

The primary reasons for the positive safety record of Nucleotome include its design and technique.

1. Design Features

The design of the Nucleotome probe has important safety advantages. The rounded tip of the probe nearly eliminates the risk of inadvertently advancing the probe through the opposite annulus once the probe is inserted into the disc. Thus, avoiding serious injury to major vessels and other abdominal structures. Another important safety feature is that material must be suctioned into the side port before being shaved by the internal cutting blade. Because of this design, the Nucleotome probe will not cut annulus or endplates. 2. Safe Technique APLD is performed under local anesthesia. This is important because it allows the physician to maintain constant communication with the patient, which minimizes risk of nerve injury. The use of general anesthesia is not advised. Furthermore, the physician works through a cannula that is less than 4 mm (which is the largest size) to limit morbidity of spinal pathologies.

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VI. APLD as Compared to Alternative Forms of Treatment

1. Open Discectomy

• APLD is safer than open discectomy. In a study of 481 open discectomy procedures, Stolke et al.11 reported a 13% complication rate, 1 death and 3 nerve injuries. Another study of open discectomy by Ramirez et al.13 analyzed 28,395 patients and reported major complication in 1 in 64 patients, a serious neurologic complication in approximately 1 in 336 and death in 1 in 1695.

• APLD is minimally invasive, whereas open discectomy requires the

dissection of tissue areas to gain access to disc space. Working percutaneously through a small cannula allows the physician to spare as much tissue as possible, thereby reducing the chance of creating spinal instability. In APLD it is not necessary to remove spinal elements to gain access to the disc space. APLD also avoids the epidural space, minimizing the risk of epidural fibrosis. Open procedures frequently disrupt the epidural space.

• APLD is more effective for properly selected patients. A recent study by

Carragee, et al.10 analyzed results of open discectomy by comparing 4 types of herniations. Results are as follows:

Herniation Type Recurrence

of Persistent Sciatica

Reherniation Reoperation Oswestry Score

Stanford Score

Fragment-Defect 27.3% 27.3% 21.2% 16.4 8.0 Fragment-Fissure 1.1% 1.1% 1.1% 11.6 9.0 Fragment-Contained 11.9% 9.5% 4.8% 9.2 8.8 No Fragment-Contained 37.5% 12.5% 6.3% 20.1 6.0

The study by Carragee et al. clearly demonstrates that patients in the “No Fragment-Contained” herniation group are poor candidates for conventional open discectomy. These are exactly the patients that are excellent candidates for APLD.

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2. Microdiscectomy

• APLD is also safer than microdiscectomy. Pappas et al.9 reported a 10.8% complication rate, 1 death and 1 major bowel injury in 654 microdiscectomies. APLD utilizes the Nucleotome Probe as the primary instrument used for decompression. This limits the amount of times that the surgeon needs to enter the disc space for removal of nucleus pulposus, whereas microdiscectomy uses manual instruments that may need to re-enter the disc several times. This may attribute to higher complication rates in microdiscectomy compared to APLD.

• Microdiscectomy is more invasive. Typically outer diameter of the cannula will be more than 5mm as compared to the 3-4mm diameter cannula used for APLD. There is evidence to show that microdiscectomy may lead to spinal instability13.

For patients that exhibit indications defined previously, APLD should be considered after conservative treatment and before more invasive treatments, such as open discectomy and microdiscectomy. APLD has proven effective and spares more healthy tissue than these alternative methods. Furthermore, APLD does not put the patient at undue risk and/or on track for potentially worsening pathologies.

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VII. Cost Benefits

APLD is much more cost effective than alternative treatments mentioned.

• APLD is done on an outpatient basis, under local anesthesia, making it cost effective. In a study by Maroon17 of 1054 patients, operating time averaged 1.1 hours. Average post operative time was 6.5 hours, with 78% of the patients being released on the same day. A study by Kambin et al.18 of microdiscectomy patients demonstrated an average hospital stay of 2.4 days. Many APLD patients are sent home with just a bandage or a single suture which limits costs.

• It has been demonstrated that 70% of patients are able to return to work

within 2 weeks of an APLD procedure.3,4 Davis et al.,7 compared a group of patients that underwent APLD versus open laminectomies and microdiscectomies and found that only 1 in 66 patients were able to return to work within 2 weeks following a laminectomy or microdiscectomy.

• The average hospital charge for APLD is less than half of the cost when compared to microdiscectomy and laminectomy.7

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References

Reference Number

Study

1 Mooney V., Percutaneous Discectomy, Spine: State of the Art Review, Jan 1989: Vol. 3, No. 1: 103-112.

2

Onik, G., Mooney, V., Maroon J., et al: Automated Percutaneous Discectomy: A Prospective Multi-Institutional Study, Neurosurgery 1990: Vol. 26, No. 2: 228-233

3

Davis G., Onik G., Helms C., Automated Percutaneous Discectomy, Spine 1991: Vol. 16, No. 13: 359-363

4

Gill K., Blumenthal S., Clinical Experience with Automated Percutaneous Discectomy: The Nucleotome System, Orthopedics 1991: 14: 757-760

5

Teng, et al.: Automated Percutaneous Lumbar Discectomy: A Prospective Multi-institutional Study, Journal of Vascular Interventional Radiology, Vol. 8, No. 3: 457-463

6

Bonaldi, G., Automated Percutaneous Lumbar Discectomy: technique, indications and clinical follow-up in over 1000 patients, Neuroradiology, 2003, 45: 735-743

7 Davis G., Onik G., Clinical Experience with Automated Percutaneous Lumbar Discectomy, Clinical Orthopaedics and Related Research, 1989: Jan., No. 238: 98-103.

8 Onik: Percutaneous Diskectomy in the Treatment of Herniated Lumbar Disks, Spine Interventions, 2000

9 Pappas, et al., Outcome Analysis in 654 Surgically Treated Lumbar Disc Herniations. Neurosurgery, 30:862-866, 1992

10 Carragee, et al., Clinical Outcomes After Lumbar Discectomy for Sciatica: The Effects of Fragment Type and Annular Competence, The journal of Bone & Joint Surgery, Vol. 85-A, No. 1: 102-108, 2003

11 Stolke, et al., Intraoperative and postoperative complications associated with lumbar spine surgery, Spine, 14: 56-58, 1989

12 Hurme, Alaranta, Factors Predicting the Result of Surgery for Lumbar Intervertebral Disc Herniation, Spine, Vol. 12, No 9:933-938, 1987

13 Kotilainen, et al., Acta Neurochir, Wien, Vol. 10: 120-126, 1993 14 Ramirez, et al., Complications and demographic characteristics of patients undergoing

lumbar discectomy in community hospitals, Neurosurgery, 25:226-231, 1989

15 Bonaldi, et al., Percutaneous Discectomy using Onik’s Method: 3 Years Experience, Neuroradiology: 516-518, 1991

16 Revel et al., Automated percutaneous lumbar discectomy versus chemonucleolysis in the treatment of sciatica: A randomized multicenter trial. Spine. 14: 1-7, 1993

17 Maroon, J., A Retrospective Study of 1054 APLD Cases: A Twenty month follow-up at Thirty-Five U.S. Centers, Paper Thirty-seven, International Percutaneous Mtng., 1989 Spain

18 Kambin et al., Percutaneous lateral discectomy of the lumbar spine: A preliminary report, Clin. Orthop. 174: 127, 1983

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Nucleotome®

Automated Percutaneous Lumbar Discectomy

Clinical Study Summaries ARTICLE (A) TITLE Onik, G. Summation of APLD Clinical Experience, Paper Thirty

eight, Presented at the International Percutaneous Mtng., 1989, Spain

TYPE OF PAPER Retrospective Study: 10 Countries TIME FRAME November 1984 to May 1989 NUMBER OF PATIENTS

3088

SUCCESS RATE 77% OTHER POINTS

• There were not deaths, major vascular or nerve damage reported.

• The average amount of Nucleus Resected = 3.2 grams. ARTICLE (B) TITLE Mooney V., Percutaneous Discectomy, Spine: State of the Art

Review, Jan 1989: Vol. 3, No. 1: 103-112 TYPE OF PAPER Retrospective Study TIME FRAME Not Given NUMBER OF PATIENTS

64

SUCCESS RATE 75% OTHER POINTS

• Definition of success: 1. moderate to complete pain relief 2. not receiving narcotic medication 3. a return to pre-injury 4. patient had to be satisfied

• No complications reported

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ARTICLE (C)

TITLE Morris, J., Percutaneous Discectomy, Orthopedics: October 1988,

Vol. 11, No. 10: 1483-1487 TYPE OF PAPER The author reported on the Multi-Institutional Study conducted

from November 1984 to June 1987 TIME FRAME November 1984 to June 1987 NUMBER OF PATIENTS

479

SUCCESS RATE 73.5% OTHER POINTS

• Definition of success: 1. no further intervention needed 2. radicular pain moderately/totally improved 3. post-operative function was improved 4. no need for narcotic analgesics 5. both patient and surgeon satisfied

• No epidural scarring, allergic reaction, or serious neurologic complications

ARTICLE (D) TITLE Onik, G., Mooney, V., Maroon J., et al: Automated Percutaneous

Discectomy: A Prospective Multi-Institutional Study, Neurosurgery 1990: Vol. 26, No. 2: 228-233

TYPE OF PAPER Prospective, Multi-institutional Study TIME FRAME November 1984 to May 1987 NUMBER OF PATIENTS

506

SUCCESS RATE 75.2% OTHER POINTS

• Definition of success: 1. radicular pain was moderately to totally improved 2. no longer receiving narcotic analgesics 3. improved functional status 4. patient satisfaction

• Only one complication reported which was a case of discitis and was successfully treated with antibiotics.

• 18 Surgeons participated • Average hospital stay 0.3 days

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ARTICLE (E)

TITLE Davis G., Onik G., Helms C., Automated Percutaneous

Discectomy, Spine 1991: Vol. 16, No. 13: 359-363 TYPE OF PAPER Prospective Study TIME FRAME Follow-up of 2 years NUMBER OF PATIENTS

518

SUCCESS RATE 85% OTHER POINTS

• No complications reported. • 427 non-compensation patients:

371 (87%) were successful 56 (13%) were failures

• 91 compensation patients: 68 (74%) were successful 23 (26%) were failures

• Of the failures: 23 patients had extruded disc fragments

5 patients had stenosis 41 patients had no anatomic explanation and refused further surgery

• 70% were able to return to work within 2 weeks. • Most procedures done on outpatient basis, making overall

cost significantly less than microdiscectomy

ARTICLE (F)

TITLE Maroon, J., A Retrospective Study of 1054 APLD Cases: A

Twenty month follow-up at Thirty-Five U.S. Centers, Paper Thirty-seven, International Percutaneous Mtng., 1989 Spain

TYPE OF PAPER Retrospective, Multi-institutional Study TIME FRAME January 1987 to February 1988 NUMBER OF PATIENTS

1054

SUCCESS RATE 82.9% OTHER POINTS

• Only 3 complications (.002%) were reported. • 35 U.S. surgeons participated in the study. • Average of 7.4 weeks conservative treatment was attempted

prior to surgery. • Primary cause of failure was the presence of free fragments. • Average amount of nucleus material removed was 2.4

grams, with the lowest being 1.0 and the highest 8.0. • 78% of patients were released the same day, which

averaged 6.5 hours of post-operative hospital stay.

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ARTICLE (G)

TITLE Hammon, W., Percutaneous Lumbar Discectomy, Western Neurosurgical Society, April 1989

TYPE OF PAPER Retrospective Study TIME FRAME 50 NUMBER OF PATIENTS

Not mentioned

SUCCESS RATE 79% OTHER POINTS

• Definition of success: 1. return to pre-injury status 2. return to normal activities 3. return to work

• No complications were reported

ARTICLE (H)

TITLE Gill K., Blumenthal S., Clinical Experience with Automated Percutaneous Discectomy: The Nucleotome System, Orthopedics 1991: 14: 757-760

TYPE OF PAPER Retrospective Study TIME FRAME Follow-up of 2.2 to 4.5 years NUMBER OF PATIENTS

62

SUCCESS RATE 79% OTHER POINTS

• No complications were reported • Definition for success:

1. moderate to complete pain relief 2. not receiving narcotic medication 3. a return to pre-injury functions

• 93% of private paying patients were successful • 65% compensation patients were successful. • 70% of patients were able to return to work within 2 weeks

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ARTICLE (I)

TITLE Swieckicki, M., Results of Automated Percutaneous Lumbar Discectomy Compared to Laminotomy and Chemonucleolysis, Paper 22, Presented at the International Percutaneous Meeting, 1989

TYPE OF PAPER Retrospective Study TIME FRAME Follow-up from 8 to 20 months NUMBER OF PATIENTS

300 (100 in each sub-group)

SUCCESS RATE 86% OTHER POINTS

• No complications reported using APLD • Definition for success:

1. return to pre-injury status 2. return to work

• 86% of APLD patients returned to work as compared to 79% for laminotomy and 58% for chemonucleolysis

• Post-operative unemployment 2.3 months overall and APLD was the shortest with a 1.1 month average

• APLD patients had the lowest average for length of hospital stay

ARTICLE (J)

TITLE Davis G., Onik G., Clinical Experience with Automated Percutaneous Lumbar Discectomy, Clinical Orthopaedics and Related Research, 1989: Jan., No. 238: 98-103.

TYPE OF PAPER Prospective TIME FRAME Follow-up of 6 months NUMBER OF PATIENTS

200

SUCCESS RATE 77.5% OTHER POINTS

• Definition of success: 1. moderate to complete relief 2. not receiving narcotic medication 3. a return to pre-injury functions 4. satisfaction with the results

• No complications reported • 70% patients able to return to work within 2 weeks • Patients returned to work sooner after percutaneous

discectomy than after microdiscectomy or laminectomy. • APLD averaged less than half the cost of microdiscectomy

or laminectomy.

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ARTICLE (K)

TITLE Onik, Kambin, Chang: Controversy, Minimally Invasive Disc

Surgery, Nucleotome Versus Fragmentectomy: Spine, 1997 TYPE OF PAPER Clinical Debate TIME FRAME N/A NUMBER OF PATIENTS

N/A

SUCCESS RATE N/A OTHER POINTS

• No reported mortality in over 125,000 APLD procedures • Cited long term study of 222 APLD patients observed for at

least 4 years resulted in 74% success rate based on patient satisfaction and avoidance of further surgery.

• A failed central disc decompression would not preclude a successful open operation.

• Able to avoid the epidural space to minimize risk of epidural scarring

ARTICLE (L)

TITLE Bonaldi, Belloni, Prosetti, Moshini: Percutaneous Discectomy using Onik’s Method: 3 Years Experience, Neuroradiology, 1991

TYPE OF PAPER Retrospective TIME FRAME 3 years, with follow up between 11 months and 3 years 4 months NUMBER OF PATIENTS

234

SUCCESS RATE 75% overall OTHER POINTS

• 75.8% success in patients meeting protocol criteria. • 72.8% success in patients not meeting protocol criteria. • 85.7% success in patients presenting with back pain only. • Only 1 complication reported (0.26%) was disc infection,

which cleared without clinical or radiologic sequelae. • Good results obtained from older patients and patients who

had previously undergone traditional surgery.

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ARTICLE (M)

TITLE Gill, Blumenthal: Automated Percutaneous Discectomy, Long-term

clinical experience with the Nucleotome System, Acta Orthop Scand, 1993

TYPE OF PAPER Retrospective TIME FRAME 1.3 to 5 year follow-up NUMBER OF PATIENTS

109

SUCCESS RATE 79% overall OTHER POINTS

• 85% success rate in private pay patients. • 70% success rate in work comp patients. • 70% of patients were able to return to work within 2

weeks. Workers’ compensation patients average 4-6 weeks, while private pay average 3-4 days).

• No neurologic injuries or major vessel injuries occurred. • Of the 23 failures, 13 underwent posterior lumbar interbody

fusion. The remaining 10 patients underwent microdiscectomy, where free fragments were found.

• Procedure has the lowest morbidity rate of all treatment options in the care of patients with herniated lumbar discs.

ARTICLE (N)

TITLE Onik: Percutaneous Diskectomy in the Treatment of Herniated

Lumbar Disks, Spine Interventions, 2000 TYPE OF PAPER Clinical Review TIME FRAME N/A NUMBER OF PATIENTS

N/A

SUCCESS RATE N/A OTHER POINTS

• More than 140,000 procedures performed without a reported mortality.

• No reports of major nerve injury or great vessel damage in more than 50 published series.

• Diskitis rate of 0.2%, which is equivalent to discography. • Safest treatment for herniated lumbar disks, in contrast to

open diskectomy or microdiskectomy.

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ARTICLE (O)

TITLE Teng, et al.: Automated Percutaneous Lumbar Discectomy: A Prospective Multi-institutional Study, Journal of Vascular Interventional Radiology, Vol. 8, No. 3: 457-463

TYPE OF PAPER Prospective, Multi-institutional TIME FRAME 18.3 month mean follow-up NUMBER OF PATIENTS

1525

SUCCESS RATE 83% overall at 1 year OTHER POINTS

• 0.06 rate of discitis (which was only type of complication) • 86% success in patients with protrusion vs. 72% with

sequestration • 89% success in patients with back pain alone vs. 80% with

back and leg pain • 85% success in patients with symptoms < 2 yrs vs. 79% with

symptoms > 2 yrs • 84% success in patients < 60 years of age vs. 76% in patients

older than 60 • 76% success in post-surgical patients

ARTICLE (P)

TITLE Bonaldi, G., Automated Percutaneous Lumbar Discectomy: techniquindications and clinical follow-up in over 1000 patienNeuroradiology, 2003, 45: 735-743

TYPE OF PAPER Retrospective TIME FRAME 14 years of experience, with follow-up of at least 6 months in 1047

patients NUMBER OF PATIENTS

1047

SUCCESS RATE 67.5% overall OTHER POINTS

• Age range 15-92 • Complication rate less than 1% • 79.5% success in patients aged 70 or more • 78% success in patients who had previously undergone

open disc surgery at the same level and had recurrent disc protrusion after 6 months or more

• 2 cases of discitis (0.17%) • 0.95% complication rate

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ARTICLE (Q)

TITLE Castro, HM., et al; Restriction of Indication for Automated Percutaneous Lumbar Discectomy Based on Computed Tomographic Discography, Spine, 17, 1239-1243, 1992

TYPE OF PAPER Prospective TIME FRAME 14 Months with 3-7 month follow-up NUMBER OF PATIENTS

97

SUCCESS RATE 53% in first 67 patients 80% in second 30 patients with revised criteria

OTHER POINTS • No complications • The shape of the dye distribution inside the protruded

disc visualized by CT discography is important • Patients who had a disc protrusion with a narrow dye

base had a worse outcome. • Patients who show a broad dye based protrusion on CT

discography had much better outcomes • Of the first 67 patients, 25/31 failures had a narrow dye

based protrusion • Of the second group of 30 patients that had revised

indications, which included adding criteria for broad dye base protrusions. There was no indication if those among the 20% failures were narrow or broad based dye protrusions.

ARTICLE (R) Carragee, et al., Clinical Outcomes After Lumbar Discectomy for Sciatica: The Effects of Fragment Type and Annular Competence, The journal of Bone & Joint Surgery, Vol. 85-A, No. 1: 102-108, 2003

• APLD is more effective for properly selected patients. A recent study by Carragee, et al. analyzed results of open discectomy by comparing 4 types of herniations. Results are as follows:

Herniation Type Recurrence

of Persistent Sciatica

Reherniation Reoperation Oswestry Score

Stanford Score

Fragment-Defect 27.3% 27.3% 21.2% 16.4 8.0 Fragment-Fissure 1.1% 1.1% 1.1% 11.6 9.0 Fragment-Contained 11.9% 9.5% 4.8% 9.2 8.8 No Fragment-Contained 37.5% 12.5% 6.3% 20.1 6.0

The study by Carragee et al. clearly demonstrates that patients in the “No Fragment-Contained” herniation group are poor candidates for conventional open discectomy. These are exactly the patients that are excellent candidates for APLD.