The adjacent segment

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.

Does decompression adjacent to arthrodesis in the lumbar spine predispose patients to adjacent segment degeneration and disease: A retrospective analysis

Background

The treatment for multi-level spinal stenosis in the setting of single-level instability is a common operative scenario for surgeons who treat degenerative lumbar spine pathology. However, there is conflicting evidence regarding the inclusion of adjacent "stable" levels in the arthrodesis construct because of the potential for iatrogenic instability placed on those segments with decompressive laminectomy alone. This study aims to determine whether decompression adjacent to arthrodesis in the lumbar spine is a risk factor for adjacent segment disease (AS Disease).

Methods

A retrospective analysis identified consecutive patients over a three-year period who underwent single-level posterolateral lumbar fusion (PLF) in the setting of single or multi-level spinal stenosis. Patients were required to have a minimum of two-year follow-up. AS Disease was defined as the development of new radicular symptoms referable to a motion segment adjacent to the lumbar arthrodesis construct. The incidence of AS Disease and reoperation rates were compared between cohorts.

Results

133 patients met the inclusion criteria with an average follow-up of 54 months. Fifty-four patients had a PLF with adjacent segment decompression, and 79 underwent a single-segment decompression and PLF. 24.1% (13/54) of patients who had a PLF with adjacent level decompression developed AS Disease resulting in a 5.5% (3/54) reoperation rate. 15.2% (12/79) of patients who did not receive an adjacent level decompression developed AS Disease resulting in a reoperation rate of 7.5% (6/79). There was neither a significantly higher rate of AS Disease (p = 0.26) nor reoperation (p = 0.74) between the cohorts.

Conclusions

Decompression adjacent to single-level PLF was not associated with an increased rate of AS Disease relative to single-level decompression and PLF.

Crossing the Cervicothoracic Junction in Multilevel Cervical Arthrodesis: A Systematic Review & Meta-Analysis

INTRODUCTION

In multisegment cervical arthrodeses, a common clinical dilemma for the surgeon is whether to extend the fusion past the cervicothoracic junction (CTJ).

OBJECTIVE

This meta-analysis compares clinical outcomes and radiological parameters when crossing and not crossing the CTJ.

METHODS

Our outcomes of interest included overall reoperation, successful fusion, adjacent segment disease (ASD) leading to revision surgery, estimated blood loss (EBL), length of stay (LOS). We also studied the postoperative change in radiological parameters - cervical sagittal vertical axis (cSVA), cervical lordosis (CL), and T1 slope (T1S) - and change in Neck Disability Index (NDI) and neck pain in Visual Analog Scale (VAS).

RESULTS

Thirteen studies with 1,720 patients were included. There were 974 (56.6%) patients in the non-crossing group and 746 (43.4%) patients in the crossing group. Non-crossing was associated with a higher risk of overall reoperation (RR=1.56; 95% CI:0.98-2.47) and ASD requiring revision surgery (RR=2.82; 95% CI:1.33-5.98; number-needed-to-harm = 22). The non-crossing group had lower EBL by 175 mL and shorter LOS by one day; the latter finding was only trending towards statistical significance. Successful fusion, as well as changes in cSVA, CL, NDI, and VAS were not different between the two groups at a statistically significant level.

CONCLUSIONS

In multilevel cervical arthrodesis, not crossing the CTJ is associated with a higher risk of overall reoperation and ASD requiring reoperation than crossing the CTJ, along with lower EBL and LOS. Differences in successful fusion, patient-reported outcomes, and sagittal radiological parameters were not significant.

Clinical Application of Ceramics in Anterior Cervical Discectomy and Fusion: A Review and Update

STUDY DESIGN

Narrative review.

OBJECTIVES

Anterior cervical discectomy and fusion (ACDF) is a reliable procedure, commonly used for cervical degenerative disc disease. For interbody fusions, autograft was the gold standard for decades; however, limited availability and donor site morbidities have led to a constant search for new materials. Clinically, it has been shown that calcium phosphate ceramics, including hydroxyapatite (HA) and tricalcium phosphate (TCP), are effective as osteoconductive materials and bone grafts. In this review, we present the current findings regarding the use of ceramics in ACDF.

METHODS

A review of the relevant literature examining the clinical use of ceramics in anterior cervical discectomy and fusion procedures was conducted using PubMed, OVID and Cochrane.

RESULT

HA, coralline HA, sandwiched HA, TCP, and biphasic calcium phosphate ceramics were used in combination with osteoinductive materials such as bone marrow aspirate and various cages composed of poly-ether-ether-ketone (PEEK), fiber carbon, and titanium. Stand-alone ceramic spacers have been associated with fracture and cracks. Metallic cages such as titanium endure the risk of subsidence and migration. PEEK cages in combination with ceramics were shown to be a suitable substitute for autograft.

CONCLUSION

None of the discussed options has demonstrated clear superiority over others, although direct comparisons are often difficult due to discrepancies in data collection and study methodologies. Future randomized clinical trials are warranted before definitive conclusions can be drawn.

What are the associative factors of adjacent segment degeneration after anterior cervical spine surgery? Comparative study between anterior cervical fusion and arthroplasty with 5-year follow-up MRI and CT

PURPOSE

It is well known that arthrodesis is associated with adjacent segment degeneration (ASD). However, previous studies were performed with simple radiography or CT. MRI is most sensitive in assessing the degenerative change of a disc, and this is the first study about ASD by radiography, CT and MRI. We sought to factors related to ASD at cervical spine by an MRI and CT, after anterior cervical spine surgery.

MATERIALS AND METHODS

This is a retrospective cross-sectional study of cervical disc herniation. Patients of cervical disc herniation with only radiculopathy were treated with either arthroplasty (22 patients) or ACDF with cage alone (21 patients). These patients were required to undergo MRI, CT and radiography preoperatively, as well as radiography follow-up for 3 months and 1 year, and we conducted a cross-sectional study by MRI, CT and radiography including clinical evaluations 5 years after. Clinical outcomes were assessed using VAS and NDI. The fusion rate and ASD rate, and radiologic parameters (cervical lordosis, operated segmental height, C2-7 ROM, operated segmental ROM, upper segmental ROM and lower segmental ROM) were measured.

RESULTS

The study groups were demographically similar, and substantial improvements in VAS (for arm) and NDI (for neck) scores were noted, and there were no significant differences between groups. Fusion rates were 95.2% in the fusion group and 4.5% in the arthroplasty group. ASD rates of the fusion and arthroplasty groups were 42.9 and 50%, respectively. Among the radiologic parameters, operated segmental height and operated segmental ROM significantly decreased, while the upper segmental ROM significantly increased in the fusion group. In a comparative study between patients with ASD and without ASD, the clinical results were found to be similar, although preexisting ASD and other segment degeneration were significantly higher in the ASD group. C2-7 ROM was significantly decreased in ASD group, and other radiologic parameters have no significant differences between groups.

CONCLUSION

The ASD rate of 46.5% after ACDF or arthroplasty, and arthroplasty did not significantly lower the rate of ASD. ASD occurred in patients who had preexisting ASD and in patients who also had other segment degeneration. ASD may be associated with a natural history of cervical spondylosis rather than arthrodesis.

Factors affecting reoperations after anterior cervical discectomy and fusion within and outside of a Federal Drug Administration investigational device exemption cervical disc replacement trial

BACKGROUND CONTEXT

The excellent clinical results of five US Federal Drug Administration (FDA) trials approved for cervical total disc replacement (TDR) (Prestige [Medtronic Sofamor Danek, Memphis, TN, USA], Bryan [Medtronic Sofamor Danek], ProDisc-C [Synthes, West Chester, PA, USA], Kineflex|C [SpinalMotion, Mountain View, CA, USA], and Mobi-C [LDR Spine, Austin, TX, USA]) have recently been published. In these prospective randomized studies, superiority or equivalency of TDR was claimed, citing an 8.7% (23/265), 9.5% (21/221), 8.5% (9/106), 12.2% (14/115), and 6.2% (5/81) (mean = 9.02%) rate of additional related cervical surgical procedures within 2 years in control anterior cervical discectomy and fusion (ACDF) patients, respectively, compared with 1.8% (5/276), 5.8% (14/242), 1.9% (2/103), 11% (15/136), and 1.2% (2/164) (mean = 4.34%) in patients receiving the cervical TDR. The rate of reoperation within 2 years after ACDF seems unusually high.

PURPOSE

To assess the rate of and specific indications for early reoperation after ACDF in a cohort of patients receiving the ACDF as part of their customary care. These results are contrasted with similar patients receiving ACDF as the control arm of five FDA investigational device exemption (IDE) studies.

STUDY DESIGN

Multisurgeon retrospective clinical series from a single institution.

PATIENT SAMPLE

One hundred seventy-six patients with spondylotic radiculopathy or myelopathy underwent ACDF by three surgeons between 2001 and 2005 as part of their clinical practices. All patients had at least 2 years of follow-up with final follow-up within 6 months of completion of this study.

OUTCOME MEASURES

Cervical reoperation rates at 2-year follow-up and at 3.5-year follow-up.

METHODS

Review of medical records and telephone conversations were completed to determine the number of patients who had undergone a revision cervical procedure.

RESULTS

At final follow-up, complete data were available for 159 ACDF patients. Of the 48 patients who underwent single-level ACDF and met criteria for inclusion in the IDE studies, one patient (2.1%) required additional surgery (adjacent-segment degeneration) within 2 years, the duration of follow-up of the five published IDE studies. Of the 159 patients who received single or multilevel ACDF at a mean follow-up of 3.5 years, 12 patients (7.6%) had undergone revision cervical surgery, with three patients (1.9%) undergoing same-level revisions (posterior fusion) and nine patients (5.7%) undergoing adjacent anterior level fusions. Patients who underwent revision same-level surgery typically had the intervention within the first year (mean, 11 months), whereas those requiring adjacent-level fusions typically had surgery later (mean, 29 months).

CONCLUSIONS

The present study identifies a 2.1% rate of repeat surgery within 2 years of a single-level ACDF performed during routine clinical practice, which is lower than that reported in the control arm of the Prestige, ProDisc-C, Bryan, Kineflex|C, and Mobi-C FDA trials (mean=9%). Even with longer follow-up including multilevel cases, our reoperation rate (7.6%) compared favorably with the IDE rates. This discrepancy may reflect different thresholds for reoperation in the control arm of a device IDE study compared with routine clinical practice. Additionally, patients enrolled in the single-level-only IDE trial may have received multilevel procedures outside of the study. This factor could result in a higher rate of subsequent surgeries at adjacent levels not addressed at the index procedure. These data suggest that we need to better understand factors driving treatment and, in particular, decisions to reoperate both in and outside of a device trial.

Adjacent-level degeneration after cervical disc arthroplasty versus fusion

INTRODUCTION

The principal objective of this study was to evaluate the incidence of adjacent-segment degeneration (ASD) in patients who underwent cervical disc arthroplasty (CDA) as compared with anterior cervical discectomy and fusion (ACDF).

METHODS

It is a prospective cohort study of patients with a single-level cervical degenerative disc disease from C3 to C7 who underwent CDA or ACDF between January 2004 and December 2006, with a minimum follow-up of 3 years. The patients were evaluated pre- and postoperatively with the visual analog scale (VAS), the neck disability index (NDI), and a complete neurological examination. Plain radiographic assessments included sagittal-plane angulation, range of motion (ROM), and radiological signs of ASD.

RESULTS

One hundred and five patients underwent ACDF and 85 were treated with CDA. The postoperative VAS and NDI were equivalent in both groups. The ROM was preserved in the CDA group but with a small decreased tendency within the time. Radiographic evidence of ASD was found in 11 (10.5%) patients in the ACDF group and in 7 (8.8%) subjects in the CDA group. The Kaplan-Meier survival analysis for the ASD occurrence did not reach statistically significant differences (log rank, P = 0.72).

CONCLUSIONS

Preservation of motion in the CDA patients was not associated with a reduction of the incidence of symptomatic adjacent-segment disease and there may be other factors that influence ASD.

Minimally invasive versus open approach for cervical laminoforaminotomy

BACKGROUND

Minimally invasive posterior cervical foraminotomy for radicular symptoms has become more prevalent. The reported experience with microscopic tubular assisted posterior cervical laminoforaminotomy (MTPF) for the treatment of radicular pain is lacking. Tubular assisted techniques have been considered to offer significant benefit, over open procedures, in terms of minimizing tissue damage, operative time, blood loss, analgesic requirements and length of hospital stay. We hypothesized that MTPF reduces post-operative analgesic requirements and length of hospital stay over the traditional open laminoforaminotomy, with no difference in complication rates and, secondly, that MTPF is comparable to endoscopic posterior foraminotomy (EPF).

METHODS

We conducted a retrospective review of 107 patients who underwent posterior cervical laminoforaminotomy for radicular pain between 1999 and 2009. Patient demographics, intra-operative parameters, length of hospitalization, post-operative analgesic use, complications and short-term neurological outcome were compared between groups.

RESULTS

Between 1999 and 2009, a total of 107 patients were identified to have undergone a cervical foraminotomy. An open approach was used in 65 patients, while 42 underwent MTPF. Operative time and complications were comparable between groups. Significant differences favoring MTPF were observed in operative blood loss, post-operative analgesic use and length of hospital stay (p<0.001). All results were comparable to previous reports utilizing EPF.

CONCLUSIONS

MTPF for the treatment of cervical radiculopathy significantly reduces blood loss, post-operative analgesic use and length of hospital stay compared to the standard open approach. Operative time and complication rates were comparable between both techniques, whilst MTPF offered similar results compared to EPF.

Five-year outcome of stand-alone fusion using carbon cages in cervical disc arthrosis

From January 1, 2001 to December 31, 2003, in the Neurosurgery Department of Rome University o "Sapienza," 167 patients underwent anterior surgery for cervical spondylodiscoarthrosis. The levels treated by the anterior stand-alone technique were: C3-C4 (11%), C4-C5 (19%), C5-C6 (40%), and C6-C7 (30%). All patients underwent left anterior presternocleidomastoid-precarotid approach, microdiscectomy, and interbody fusion using a carbon fiber cage filled with hydroxyapatite. All patients were discharged within 48 h after surgery with cervical orthosis. In one case, a hematoma of the surgical site occurred within 12 h of surgery; for this reason the patient underwent surgical revision and was discharged 4 days later. All patients have worn cervical orthosis for a mean period of 7 weeks and underwent radiological follow-up with cervical RX at 1 and 3 months after surgery. All patients underwent follow-up from 54 to 90 months after surgery, and all of them underwent cervical RX, cervical CT scans for the estimate of fusion, and evaluation of neurological status using VAS and NDI. Of 167 patients, 132 were cooperative for this study, 18 were non-cooperative, and 17 died. The estimation of fusion made by cervical CT scans with sagittal reconstruction showed complete osteointegration of the cage in 115 patients (87.1%), while it showed pseudoarthrosis in 17 patients (12.9%). In 24 patients, we observed adjacent segment degeneration, and 13 of these underwent new surgical procedures in this institute or in another hospital. Clinical evaluation with VAS and NDI showed a good outcome, with poorest benefit in patients over 60 years. The clinical analysis showed a good fusion rate in according with literature, 13% of non-fusion rate without clinical evidence and 20% of ASDegeneration but only 10% had required new surgery. We also observed that patients over 60 years of age had less satisfactory outcome, probably related with the evolution of pathophysiological degeneration of the cervical spine. In the opinion, pseudoarthrosis is caused by malpositioning of the carbon fiber cage.

[Cervical arthroplasty using the Bryan Cervical Disc System]

OBJECTIVE

Treatment of radicular or myelopathic symptoms of the vertebral segments from C2 through Th1.

INDICATIONS

Discogenic and/or spondylotic radiculopathy. Acute myelopathy. Acute or progressive functional neurological deficit. Persistent pain resistant toward conservative treatment for > 6 weeks.

CONTRAINDICATIONS

Chronic myelopathy. Spondylotic myelopathy. Infection. Tumor in the vertebral segment. Ossification of the posterior longitudinal ligament (OPLL). Metabolic bone disease. Osteoporosis. Long-lasting steroid medication. Allergy to titanium, polyurethane and ethylene oxide. Bekhterev's disease. Bony segmental fusion. Instability.

SURGICAL TECHNIQUE

Using the Bryan Cervical Disc Template Set together with magnetic resonance or computer tomographic images, the exact size of the prosthesis will be selected. The patient is lying in a supine position and the level of surgery is verified fluoroscopically. Diskectomy and decompression are performed via an anterior approach. After preparation of the implant bed, the center of the disk space is established using a transverse centering tool and inserting the Bryan cervical distractor. Before the prosthesis can be inserted, the end plates have to be milled. The prosthesis is filled with sterile saline solution and inserted. Proper fitting is verified fluoroscopically.

POSTOPERATIVE MANAGEMENT

Depending on the clinical situation postoperatively, the patient is discharged. Wound clamps are distracted on day 8, support by a cervical collar is not necessary. Light physical manipulations for muscle relaxation can be performed.

RESULTS

Since 2002, 178 patients have received at least one Bryan Cervical Disc Prosthesis. 92 patients had a complete follow- up. Examinations were performed 8 and 12 weeks, respectively, as well as 6 up to 44 months postoperatively. 29 patients received a hybrid implantation. Cobb's angle and range of motion were determined radiologically, the degree of heterotopic ossification was classified according to McAfee. Disk prosthesis placement was measured in relation to the dorsal edge of the vertebral body, the center of the spine, as well as the body axes. For clinical evaluation, the Oswestry Neck Disability Index was used, and the neurostatus was determined.

Arthroplasty in the military: a preliminary experience with ProDisc-C and ProDisc-L

OBJECT

The introduction of cervical and lumbar arthroplasty has allowed for management of cervical radiculopathy and lumbar degenerative disease in patients with the preservation of motion at the affected segment. While the early clinical outcomes of this technology appear promising, it remains unclear what activity limitations should be imposed after surgery in patients with these implants. This is of particular interest in military personnel, who may be required to return to a rigorous level of activity after surgery. The goals of the FDA trials evaluating various disc arthroplasty devices were to establish safety, efficacy, and equivalency to arthrodesis. Information regarding the level of physical performance attained and restrictions or limitations is lacking, as these were outside the objectives of these trials. Nevertheless, there data are essential for the military surgeon, who is tasked with guiding the postoperative management of patients treated with arthroplasty and returning them to full duty. While there is a single report of clinical results of lumbar arthroplasty in athletes, at this writing, there are no reports of either cervical or lumbar arthroplasty in active duty military personnel.

METHODS

The surgical database at a single, tertiary care military treatment facility was queried for all active-duty patients who underwent placement of either a cervical or lumbar arthroplasty device over a 3-year period. The authors performed a retrospective chart review to collect patient and procedural data including blood loss, length of hospital stay, tobacco use, age, rank, complications, and ability to return to full unrestricted active duty. Arthroplasty cohorts were then compared to historical controls of arthrodesis to ascertain differences in the time required to return to full duty.

RESULTS

Twelve patients were identified who underwent cervical arthroplasty. All patients returned to unrestricted full duty. This cohort was then compared with 12 patients who had undergone a single-level anterior cervical discectomy and fusion. The average time to return to unrestricted full duty for the arthroplasty group was 10.3 weeks (range 7-13 weeks), whereas that in the fusion group was 16.5 weeks. This difference between these 2 groups was statistically significant (p = 0.008). Twelve patients were identified who underwent lumbar arthroplasty. Ten (83%) of 12 patients in this group returned to unrestricted full duty. In patients who returned to full duty, it took an average of 22.6 weeks (range 12-29 weeks). This cohort was then compared with one in which patients had undergone anterior lumbar interbody fusion. Eight (67%) of 12 patients in the lumbar arthrodesis group returned to unrestricted full duty. In patients who returned to full duty, it took an average of 32.4 weeks (range 25-41 weeks). This difference was not statistically significant (p = 0.156).

CONCLUSIONS

The preliminary experience with cervical and lumbar arthroplasty at the authors' institution indicates that arthroplasty is comparable with arthrodesis and may actually expedite return to active duty. Patients are capable of returning to a high level of rigorous training and physical performance. There are no apparent restrictions or limitations that are required after 3 months in the cervical patient and after 6 months in the lumbar patient. Further prospective studies with long-term follow-up are indicated and will be of value when determining the role of arthroplasty compared to arthrodesis in the active-duty population.

Favourable long-term clinical outcome after anterior cervical discectomy. A study on a series of 125 patients undergoing surgery a mean of 11 years earlier

OBJECTIVE

This retrospective study assessed long-term clinical outcome in a series of patients undergoing anterior cervical discectomy (ACD) for treatment of myeloradiculopathy secondary to one- to two-level cervical discoarthrosis. To verify concerns about long-term adverse clinical effects following ACD, a review of literature on the topic was also made.

METHODS

The clinical course and long-term outcome of 125 consecutive patients with cervical myeloradiculopathy operated on by ACD 5 to 19 years ago (mean, 11.3 years) were reviewed. Seventy-four patients (59%) showed a clinical picture of pure radiculopathy, and 51 patients (41%) had myeloradiculopathy. Long-term clinical outcome and Visual Analog Scale (VAS) scores for neck and arm pain were recently assessed and compared with post-surgical status. Clinical outcome was graded according to the criteria of Odom et al. (JAMA 166:23-28, 36). The survey of the literature on long-term clinical outcome after ACD was internet-based.

RESULTS

Long-term clinical outcome was excellent in 61% of patients, good in 26%, satisfactory in 9% and poor in 4%. The same figures at the time of discharge were 65%, 29%, 6% and 0%, respectively. Mean long-term neck and arm pain VAS scores were 2.5 and 0.8, respectively, while postoperatively, the same values were 2.1 and 0.5. Additional discectomy at an adjacent level was performed in five patients 10 months to 8 years after the first operation.

CONCLUSIONS

In our series, 96% of patients had a sustained favourable long-term clinical outcome after ACD. These favourable results confirm data in the literature and support our preference for ACD as the simplest, fastest and cheapest surgical option for treating myeloradiculopathy secondary to one- to two-level cervical discoarthrosis.

The change of adjacent segment and sagittal balance after thoracolumbar spine surgery

OBJECTIVE

To characterize perioperative biomechanical changes after thoracic spine surgery.

METHODS

Fifty-eight patients underwent spinal instrumented fusions and simple laminectomies on the thoracolumbar spine from April 2003 to October 2008. Patients were allocated to three groups; namely, the laminectomy without fusion group (group I, n = 17), the thoracolumbar fusion group (group II, n = 27), and the thoracic spine fusion group (group III, n = 14). Sagittal (ADS) and coronal (ADC) angles for adjacent segments were measured from two disc spaces above lesions at the upper margins, to two disc spaces below lesions at the lower margins. Sagittal (TLS) and coronal (TLC) angles of the thoracolumbar junction were measured from the lower margin of the 11th thoracic vertebra body to the upper margin of the 2nd lumbar vertebra body on plane radiographs. Adjacent segment disc heights and disc signal changes were determined using simple spinal examinations and by magnetic resonance imaging. Clinical outcome indices were determined using a visual analog scale.

RESULTS

The three groups demonstrated statistically significant differences in terms of angle changes by ANOVA (p < 0.05). All angles in group I showed significantly smaller angles changes than in groups II and III by Turkey's multiple comparison analysis. Coronal Cobb's angles of the thoracolumbar spine (TLC) were not significantly different in the three groups.

CONCLUSION

Postoperative sagittal balance is expected to change in the adjacent and thoracolumbar areas after thoracic spine fusion. However, its prevalence seems to be higher when the thoracolumbar spine is included in instrumented fusion.