Facet Problems, Revision Surgery, Fusion

[Harrison]

Below is a hodge-podge of abstracts. I am hoping to stay current on newer techniques involving the use of harware to secure facets for stenosis and (perhaps) revisions, though the first article is dated. I will continue my search, as there is much to know. Here are a few excerpts I found.
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Selective decompression and translaminar articular facet screw fixation for lumbar canal stenosis and disc protrusion.

Benini A, Magerl F.
Neurosurgical Department, Kantonsspital, St. Gall, Switzerland.
A technique is described for lumbar canal stenosis and disc protrusion combining safe and selective decompression and translaminar screw fixation. After experience with 166 cases from 1987 to 1991, we consider this technique particularly suitable for the treatment of lumbar spinal stenosis and also for the few cases of lumbar disc displacement which need a primary fusion.

Spine. 2009 May 15;34(11):E384-90

An anatomic and radiographic study of lumbar facets relevant to percutaneous transfacet fixation.

Su BW, Cha TD, Kim PD, Lee J, April EW, Weidenbaum M, Albert TJ, Vaccaro AR.
Department of Orthopaedic Surgery, Orthopaedic Research Laboratory, NY Presbyterian Hospital, New York, NY10032, USA. Bws7 (at) columbia.edu

STUDY DESIGN: An anatomic study of lumbar facet anatomy for transfacet fixation.

OBJECTIVE: Describe the ideal starting point and trajectory for percutaneous transfacet fixation.

SUMMARY OF BACKGROUND DATA: Percutaneous transfacet fixation is gaining popularity for posterior stabilization after anterior lumbar interbody fusion. Despite biomechanical and clinical studies, there are no anatomic guidelines for safe placement of percuatenous transfacet screws.

METHODS: Eighty L3-S1 facet joints from embalmed cadaveric spines were analyzed. Linear and angular measurements of the facets were recorded. Under direct visualization, the segments were pinned with an ipsilateral transfacet technique. The degrees of angulation in the sagittal and axial plane were recorded. The distances of the starting point relative to landmarks of the superior body were measured. Under fluoroscopy, radiographic parameters for ideal visualization of the pin and pin ending points were determined.

RESULTS: Inferior and superior facet heights ranged from 15.7 to 17.5 mm at all levels. The percentage of inferior facet extending below the L3 and L4 end plates was 84% and 86% respectively and decreased at L5 to 72%. The percentage of superior facet extending above the end plate ranged from 36% to 44% at all levels. The transverse facet angle progressively increased from L3 to S1. The L2-L3 segments could not be instrumented from the ipsilateral side due to the vertical facet orientation. For L3-S1 segments, the starting point in the coronal plane is based on the superior body of the instrumented segment and should be in line with the medial border of the pedicle in the medial-lateral direction and in line with the inferior end plate in the cranial-caudal direction. The screw should be laterally angulated approximately 15 degrees in the axial plane approximately 30 degrees caudally in the sagittal plane. The screw should end in the inferolateral quadrant of the pedicle on the AP radiograph and at the pedicle-vertebral body junction on the lateral radiograph. 35 degrees of axial rotation is the optimal fluoroscopic view for confirming screw placement.

CONCLUSION: Ipsilateral transfacet fixation can be successfully performed in the L3-S1 segments by using the inferior end plate and medial pedicle wall of the superiorly instrumented level as anatomic landmarks in conjunction with axial and sagittal angles of insertion.

Spine J. 2009 Jan-Feb;9(1):96-102. Epub 2008 Apr 25.

Effect of the Total Facet Arthroplasty System after complete laminectomy-facetectomy on the biomechanics of implanted and adjacent segments.

Phillips FM, Tzermiadianos MN, Voronov LI, Havey RM, Carandang G, Renner SM, Rosler DM, Ochoa JA, Patwardhan AG.

RushUniversityMedicalCenter, Chicago, IL, USA.
BACKGROUND CONTEXT: Lumbar fusion is traditionally used to restore stability after wide surgical decompression for spinal stenosis. The Total Facet Arthroplasty System (TFAS) is a motion-restoring implant suggested as an alternative to rigid fixation after complete facetectomy.

PURPOSE: To investigate the effect of TFAS on the kinematics of the implanted and adjacent lumbar segments.

STUDY DESIGN: Biomechanical in vitro study.

METHODS: Nine human lumbar spines (L1 to sacrum) were tested in flexion-extension (+8 to -6Nm), lateral bending (+/-6Nm), and axial rotation (+/-5Nm). Flexion-extension was tested under 400 N follower preload. Specimens were tested intact, after complete L3 laminectomy with L3-L4 facetectomy, after L3-L4 pedicle screw fixation, and after L3-L4 TFAS implantation. Range of motion (ROM) was assessed in all tested directions. Neutral zone and stiffness in flexion and extension were calculated to assess quality of motion.

RESULTS: Complete laminectomy-facetectomy increased L3-L4 ROM compared with intact in flexion-extension (8.7+/-2.0 degrees to 12.2+/-3.2 degrees, p<.05) lateral bending (9.0+/-2.5 degrees to 12.6+/-3.2 degrees, p=.09), and axial rotation (3.8+/-2.7 degrees to 7.8+/-4.5 degrees p<.05). Pedicle screw fixation decreased ROM compared with intact, resulting in 1.7+/-0.5 degrees flexion-extension (p<.05), 3.3+/-1.4 degrees lateral bending (p<.05), and 1.8+/-0.6 degrees axial rotation (p=.09). TFAS restored intact ROM (p>.05) resulting in 7.9+/-2.1 degrees flexion-extension, 10.1+/-3.0 degrees lateral bending, and 4.7+/-1.6 degrees axial rotation. Fusion significantly increased the normalized ROM at all remaining lumbar segments, whereas TFAS implantation resulted in near-normal distribution of normalized ROM at the implanted and remaining lumbar segments. Flexion and extension stiffness in the high-flexibility zone decreased after facetectomy (p<.05) and increased after simulated fusion (p<.05). TFAS restored quality of motion parameters (load-displacement curves) to intact (p>.05). The quality of motion parameters for the whole lumbar spine mimicked L3-L4 segmental results.

CONCLUSIONS: TFAS restored range and quality of motion at the operated segment to intact values and restored near-normal motion at the adjacent segments.

[JKDE302]

damn I need cervical facet help...a.s.a.p