Mimally invasive TLIF w/Hydrocision (interesting BMP data too)

[mmglobal]

Last week I was able to attend a seminar titled:

Critical Appraisal of Lumbar Interbody Fusion Techniques, Materials and Biologics on Fusion Outcomes

It was a very interesting comparison of fusion techniques. It seemed that it was mostly aimed at proving out a surgical instrument called SpineJet (by Hydrocision). This device allows the surgeon to simultaneously cut and aspirate the nucleus with a single tool that uses a high speed water jet as a scalpel and suction device (taking advantage of the moving water to generate a venturi). The talk was given by Larry Khoo of UCLA. In the past few years, he’s become a pretty heavy hitter in the development of minimally invasive spine devices and techniques. I’ve written about other presentations he’s made.

One major issue in TLIF (transforaminal lumbar interbody fusion) is the potential for nerve injury caused by the trauma of the surgery. This study compared the Hycrocision procedure to traditional techniques. One portion of the study compared the hydrocision technique to conventional techniques in preparing disc spaces for TLIF in 27 cadaveric lumbar discs. Because the SpineJet tool performs double duty and provides suction and manipulation of the tissues, the average number of instrument insertions and withdrawals per level was reduced from 102 using conventional techniques to 36 with the SpineJet. That is a 65% decrease in the number of times the surgeon needs to pass the tools by the dura and exiting nerve roots. With this technique, there was no difference in the soft tissue removed. Another impressive number was the 16% increase of endplate decortications (% of endplate surface area) improving from 31% to 36%, presumably leading to better fusion rates. There was also a substantial decrease (23%) in number of damaged endplates with Hydrocision.

In the “live patient” study, there were 302 TLIF patients. 54 had open TLIF, while 248 had minimally invasive TLIF. Fusion rates were identical. Blood loss, length of hospital stay, and OR time were all substantially improved in the hydrocision patients. As expected, very early evaluation of pain meds required, and pain scors are all better for the MISS, whild 2 year data is much closer (but still better for the MISS group.)

Here is what I really wanted to convey… this is very interesting. The hydrocision group as split into 2 (almost) halves. 76 patients had hydrocision, while 68 had hydrocision +BMP. 104 patients had the traditional TLIF.

The fusion rate for the traditional TLIF group was 91.3%

The fusion rate for the hydrocision group was 93.6%

The fusion rate for the hydrocision +BMP group was 96.6%. Sounds good? Read on!

Post-op radiculopathy occurred in 6, 2, 3 patients for the 3 groups (traditional, hydrocision, hydrocision +BMP) This really seems to prove out the value of an average of 36 passes versus 102!

Late radiculopathy (unresolved or late onset?) occurred in 3, 1, 12 patients. That’s 22% in the BMP group, while only 8.7% in the traditional group and 3.9% in the hydrocision without BMP group. This is born out by the reoperation numbers… 4, 3, 7 in the 3 groups.

This study seems to demonstrate the advantage of the improved, less traumatic technique, but the addition of BMP generated much worse results. Presumably, all that bone growth promoted by the BMP, increasing the fusion rate, also increases the complication and reoperation rates.

This is all from my notes and memory, so take it all with a grain of salt. It was a very interesting seminar. I hope you find this info useful.

All the best,

Mark

[Justin]

Mark,

That was an interesting read. Thanks for sharing... Any technique that is less traumatic is a great thing!

-Dr. J

[Tim]

Thanks for posting this interesting article.
The 22% figure for late onset radiculopathy in the BMP group is very worrying. It’s the worst figure I’ve seen regarding complications relating to BMP use in lumbar fusions and if taken at face value must seriously call into question the current increasing use of BMP. When I questioned one surgeon regarding this issue he stated that in his opinion a lot of problems with BMP are caused by surgeon error – by which I suppose he meant incorrect placement of the BMP within the prepared disc space. I suppose it makes sense that if the majority of the BMP material is packed to the front of the disc space then the risk of overgrowth is minimised. My understanding is probably oversimplified but it would be nice if more data were available to fully understand the level of complications associated with BMP.
The hydrocision apparatus sounds very promising – how long has it been around and how established is it’s usage in current operating theatres?
All the best
Tim

[mmglobal]

Originally Posted by Tim

The 22% figure for late onset radiculopathy in the BMP group is very worrying. It’s the worst figure I’ve seen regarding complications relating to BMP use in lumbar fusions and if taken at face value must seriously call into question the current increasing use of BMP.

This is the problem with so much of the data we get. Is BMP a problem or is this application a problem? Don't go to those docs for BMP??? Is there something specific about this technique that makes appropriate application of BMP an issue?

[Maria]

Thanx Mark. Don't know what to think except once again I'm glad to date I didn't become a personal recipient of BMP.

[mmglobal]

When I started looking at this, I found a press release from 2006 that talks about Stan Schiffer being the most experienced hydrocision user at the time. He called me today and we spent about 1/2 hour discussing the state of spine, including hydrocision. He still uses it, but for discectomy, not fusion prep. What he does is much different than the 'normal' use, but he likes the system and gets excellent results with it. I asked how many cases he'd done with hydrocision and he's stopped counting. "Hundreds and hundreds was his reply." The press relase talked about 100 cases more than 2 years ago.

It's been a while since we'd spoken, so it was great to catch up with him. We met at my first spine conference in 2002 and he's been very helpful to me and many of my clients since then. He's a pioneer in Minimally Invasive Spine Surgery and I've been up to see him do surgery (cervical and lumbar) several times. Nice guy... good surgeon. It's interesting that the recent seminar brings me back to one of the first doctors I'd met in my new life after my surgery.

[jsewell]

Thanks Mark for posting and explaining this, it is very interesting
judy

[Maria]

any updates Mark?

[mmglobal]

I just texted one of the study authors... I'll let you know if I hear anything interesting.

Mark