The effect of cervical posterior foraminotomy on segmental range of motion in the setting of total disc arthroplasty

Revision Strategies for Cervical Disc Arthroplasty

STUDY DESIGN

Narrative review.

OBJECTIVE

To review indications and strategies for revision of cervical disc arthroplasty (CDA).

SUMMARY OF BACKGROUND DATA

No data were generated as part of this review.

METHODS

A narrative review of the literature was performed.

RESULTS

No results were generated as part of this review.

CONCLUSIONS

CDA is a proven, motion-sparing surgical option for the treatment of myelopathy or radiculopathy secondary to cervical degenerative disc disease. As is the case with any operation, a small percentage of CDA will require revision, which can be a technically demanding endeavor. Here we review available revision strategies and associated indications, a thorough understanding of which will aid the surgeon in finely tailoring their approach to varying presentations.

Impact of Posterior Cervical Foraminotomy Before or After Cervical Disk Replacement: Current Evidence

STUDY DESIGN

Narrative review.

OBJECTIVES

The purpose of this study was to provide a review of the current evidence on the impact of posterior cervical foraminotomy (PCF) performed before or after cervical disk replacement (CDR).

SUMMARY OF BACKGROUND DATA

The impact of PCF on outcomes in the setting of CDR is an evolving field, given the recent widespread adoption of CDR and the relative rarity of patients who have undergone both procedures.

METHODS

A literature search was conducted using PubMed to determine current evidence regarding the indications, outcomes, and biomechanical effects of CDR and PCF when performed alone or in combination.

RESULTS

When radicular symptoms persist following PCF, a CDR can be safely performed to provide further decompression. Conversely, a PCF can be safely performed following CDR for these same indications. The biomechanical effects of these procedures in combination demonstrate maintained stability when the facetectomy is less than 50% of the facet joint. Studies demonstrate that stability is not significantly decreased by the presence, amount, or level of posterior foraminotomies in the setting of CDR.

CONCLUSIONS

A PCF can be safely performed before or after cervical disk arthroplasty for recurrent radicular symptoms.

LEVEL OF EVIDENCE

Level V.

Biomechanical evaluation of the ProDisc-C stability following graded posterior cervical injury

OBJECTIVEThere are limited data regarding the implications of revision posterior surgery in the setting of previous cervical arthroplasty (CA). The purpose of this study was to analyze segmental biomechanics in human cadaveric specimens with and without CA, in the context of graded posterior resection.METHODSFourteen human cadaveric cervical spines (C3-T1 or C2-7) were divided into arthroplasty (ProDisc-C, n = 7) and control (intact disc, n = 7) groups. Both groups underwent sequential posterior element resections: unilateral foraminotomy, laminoplasty, and finally laminectomy. Specimens were studied sequentially in two different loading apparatuses during the induction of flexion-extension, lateral bending, and axial rotation.RESULTSRange of motion (ROM) after artificial disc insertion was reduced relative to that in the control group during axial rotation and lateral bending (13% and 28%, respectively; p < 0.05) but was similar during flexion and extension. With sequential resections, ROM increased by a similar magnitude following foraminotomy and laminoplasty in both groups. Laminectomy had a much greater effect: mean (aggregate) ROM during flexion-extension, lateral bending, and axial rotation was increased by a magnitude of 52% following laminectomy in the setting of CA, compared to an 8% increase without arthroplasty. In particular, laminectomy in the setting of CA introduced significant instability in flexion-extension, characterized by a 90% increase in ROM from laminoplasty to laminectomy, compared to a 16% increase in ROM from laminoplasty to laminectomy without arthroplasty (p < 0.05).CONCLUSIONSForaminotomy and laminoplasty did not result in significant instability in the setting of CA, compared to controls. Laminectomy alone, however, resulted in a significant change in biomechanics, allowing for significantly increased flexion and extension. Laminectomy alone should be used with caution in the setting of previous CA.

Morphometric Analysis for Surgical Treatment of Cervical Discopathy by Posterior Laminoforaminotomy: Radiologic Study and Technical Note

BACKGROUND

The main concern with the posterior approach is the risk of postoperative segmental instability. The most commonly cited rule is that removal of the medial half of the articular facet provides adequate surgical exposure and has no effect on stability. The aim of this study was to define the areas of the articular processes in the cervical spine that can be safely removed.

METHODS

Computed tomography scans of 50 cervical spines were analyzed. Measurements were analyzed for bone removal assuming the standard technique of posterior laminoforaminotomy. The width of the facet was measured at the level of the widest dimension. The height of the articular process was taken from the bottom (in the case of inferior process) or top (in the case of superior process) of the process.

RESULTS

The mean width of the articular process ranged from 11.8 ± 1.5 mm (range, 8.3-15.7 mm) at the C2-C3 level to 14.6 ± 1.7 mm at the C6-C7 level. At the cervicothoracic junction (C7-T1 level), the mean width decreased to 14.0 ± 1.7 mm. The mean value for both sides when the inferior articular process was measured at all levels was 5.0 ± 1.4 mm (range, 4.5-5.8 mm). The mean height of the superior articular process was 7.7 ± 1.5 mm (range, 6.8-8.3 mm).

CONCLUSIONS

Based on our findings, our "5-5-7 mm rule" corresponds to the amount of bone removal for each step of the laminoforaminotomy.

Posterior Cervical Foraminotomy: Indications, Technique, and Outcomes

Cervical radiculopathy presents with upper extremity pain, decreased sensation, and decreased strength caused by irritation of specific nerve root(s). After failure of conservative management, surgical options include anterior cervical decompression and fusion, disk arthroplasty, and posterior cervical foraminotomy. In this review, we discuss indications, techniques, and outcomes of posterior cervical laminoforaminotomy.