Emerging Techniques in Spinal Surgery
Disclosures
Michael Vitale, MD
Introduction
Surgical treatment of spinal conditions is changing at a rapid pace--
perhaps more than any other field of orthopaedics. Minimally invasive
techniques, new spinal implants, and genetically engineered biologic
agents have already altered the practice of spinal surgery and
promise to improve patient outcomes. Many studies presented at the
68th Annual Meeting of the American Academy of Orthopaedic Surgeons
offered exciting new findings in this field.
Thorascopic Instrumentation: Correction and Fusion of Thoracic
Scoliosis
The use of a thoracoscopic, anterior approach to spinal surgery has
recently become more widespread. This technique holds the promise of
less blood loss, less morbidity than thoracotomy, shorter hospital
stay, and faster recovery than standard open thoracic surgery
techniques. While thoracoscopic anterior spinal release is already a
common procedure, the design and choice of thoracoscopic
instrumentation remains a subject of controversy.
Picetti and Bueff reported[1] on a study of 50 patients with primary
thoracic scoliosis who underwent correction and fusion via
thorascopically assisted instrumentation, a procedure currently
performed only in select centers. Curve correction averaged 50% for
the first 40 patients and increased to an average correction of
greater than 68% for the last 10 patients. Hypokyphosis correction
averaged 21 degrees. Fourteen complications--but no deaths--were
reported. This evolving technique is showing promise. Correction
rates are improving (as was seen with this patient population), and
blood loss and pain were reduced in comparison with standard open
techniques. In addition, increasing surgical skill has decreased both
the operative time and the subsequent rehabilitation period.
Preclinical Study Opens Doors for Further Exploration of Endoscopic
Scoliosis Repair
Eric Wall, MD, presented cutting-edge research to determine whether
spinal staples, placed endoscopically could arrest growth on the
convex part of the vertebral curve.[2] Dr. Wall reported data from
his animal (porcine) study to determine if a simple endoscopic
implant (staples) is capable of modifying spine growth without
fusion. With the correction of adding barbs to the staple blades and
adding screw fixation to the procedure, failures related to staple
loosening were overcome. Dr. Wall concluded that "Endoscopic stapling
holds potential for slowly arresting or correcting infantile,
juvenile, and young adolescent scoliosis."
Emerging Technologies and Techniques
A symposium moderated by E.N. Hanley, MD, involved leaders in the
field discussing the impact of newer percutaneous (intradiscal
electrothermy, kyphoplasty) and minimally invasive (endoscopic,
laparoscopic) procedures, as well as the effects of newer implant
designs (cages, artificial discs), to determine whether the use of
these technologic advances has actually yielded improved outcomes.[3]
On the subject of new spinal implants, Thomas Zdeblick, MD,
explained, "We are all learning about the appropriate use of these
new implants. For example, in the use of transarticular screws for C1-
C2 fractures, the new implants have clearly increased fusion rates,
decreased the need for postoperative immobilization, and have led to
better patient outcomes." However, controversy persists about other
implants, including threaded interbody cages and thoracic pedicle
screws.
Speaking on the exciting possibilities and indications for use
presented by improvements in genetically engineered growth factors,
including various bone morphogenetic proteins (BMPs), Scott Boden,
MD, predicted that "Widespread clinical use of BMP is 1 to 3 years
away." Though research in this area has been ongoing for over 30
years, new dosing regimens learned from applications to primate
models and recent improvements in the carriers that ensure that BMPs
remain where they can be used, should pave the way for practical use,
according to investigators in the field. "Once we can make bone at
will," predicted Boden, "minimally invasive techniques will take
over."
References
Picetti GD, Bueff HU. Thorascopic instrumentation: correction and
fusion of thoracic scoliosis. Program and abstracts of the 68th
Annual Meeting of the American Academy of Orthopaedic Surgeons;
February 28-March 4, 2001; San Francisco, CA. Poster PE297.
http://www.aaos.org/wordhtml/anmt2001/poster/pe297.htm
Wall E, Bylski-Austrow D, Kolata RJ, Crawford AH, Ballard ET.
Endoscopic mechanical spinal hemiepiphysiodesis modifies spine
growth. Program and abstracts of the 68th Annual Meeting of the
American Academy of Orthopaedic Surgeons; February 28-March 4, 2001;
San Francisco, CA.Abstract 010.
http://www.aaos.org/wordhtml/anmt2001/sciprog/010.htm
Hanley EN, Moderator. Spine: have emerging technologies altered
outcomes? A symposium. Program and abstracts of the 68th Annual
Meeting of the American Academy of Orthopaedic Surgeons; February 28-
March 4, 2001; San Francisco, CA.
http://www.aaos.org/wordhtml/anmt2001/sympm.htm