Revision of anterior cervical pseudoarthrosis with anterior allograft fusion and plating

Fate of pseudarthrosis detected 2 years after anterior cervical discectomy and fusion: results of a minimum 5-year follow-up

BACKGROUND CONTEXT

Prior study has shown that 70% of cervical pseudarthrosis after anterior cervical discectomy and fusion (ACDF) detected at 1 year will go on to fusion by 2 year. Pseudarthrosis detected 2 years after ACDF may have different bone healing potential compared to nonunion detected 1 year after surgery. Therefore, it might have a different clinical significance.

PURPOSE

To examine the radiographic and clinical prognosis of pseudarthrosis detected 2 years after ACDF with a minimum follow-up of 5 years.

STUDY DESIGN/SETTING

Retrospective cohort study.

PATIENTS SAMPLE

A total of 249 patients who completed a 5-year follow-up after ACDF.

OUTCOMES MEASURES

Clinical outcomes such as neck pain visual analogue scale (VAS), arm pain VAS, and neck disability index (NDI) and radiographic assessment such as X-ray, computed tomography (CT) scan.

METHODS

A total of 249 patients who completed a 5-year follow-up after ACDF were retrospectively reviewed. Patients who were diagnosed with pseudarthrosis at 2 years postoperatively were included. Fusion, neck pain VAS, arm pain VAS, and NDI were assessed. The results were compared between the union group (patients who achieved union), and the nonunion group (patients with pseudarthrosis) at 5 years postoperatively.

RESULTS

Among the patients who had pseudarthrosis at 2 years postoperatively, the fusion rate at 5 years was 32.6% (14/43). While the union group showed continued improvements in neck pain VAS, arm pain VAS, and NDI until 5 years, the nonunion group showed significant worsening of arm pain VAS and NDI at 5 years, with the values of neck pain VAS, arm pain VAS, and NDI being significantly worse than those of the union group at 5 years.

CONCLUSION

The incidence of pseudarthrosis detected at 2 years postoperatively after ACDF was 67.4%, and it remained unfused at 5 years postoperatively. Nonunion identified 2 years after ACDF may be considered a poor prognostic factor because it has less potential to achieve fusion with further follow-up and a higher chance of worsening clinical symptoms. Therefore, the presence of fusion at the 2-year follow-up can be considered an indicator of the success of the surgery.

Pseudoarthrosis after anterior cervical discectomy and fusion: rate of occult infections and outcome of anterior revision surgery

BACKGROUND

Pseudoarthrosis after anterior cervical discectomy and fusion (ACDF) is relatively common and can result in revision surgery. The aim of the study was to analyze the outcome of patients who underwent anterior revision surgery for pseudoarthrosis after ACDF.

METHODS

From 99 patients with cervical revision surgery, ten patients (median age: 48, range 37-74; female: 5, male: 5) who underwent anterior revision surgery for pseudoarthrosis after ACDF with a minimal follow up of one year were included in the study. Microbiological investigations were performed in all patients. Computed tomography (CT) scans were used to evaluate the radiological success of revision surgery one year postoperatively. Clinical outcome was quantified with the Neck Disability Index (NDI), the Visual Analog Scale (VAS) for neck and arm pain, and the North American Spine Society Patient Satisfaction Scale (NASS) 12 months (12-60) after index ACDF surgery. The achievement of the minimum clinically important difference (MCID) one year postoperatively was documented.

RESULTS

Occult infection was present in 40% of patients. Fusion was achieved in 80%. The median NDI was the same one year postoperatively as preoperatively (median 23.5 (range 5-41) versus 23.5 (7-40)), respectively. The MCID for the NDI was achieved 30%. VAS-neck pain was reduced by a median of 1.5 points one year postoperatively from 8 (3-8) to 6.5 (1-8); the MCID for VAS-neck pain was achieved in only 10%. Median VAS-arm pain increased slightly to 3.5 (0-8) one year postoperatively compared with the preoperative value of 1 (0-6); the MCID for VAS-arm pain was achieved in 14%. The NASS patient satisfaction scale could identify 20% of responders, all other patients failed to reach the expected benefit from anterior ACDF revision surgery. 60% of patients would undergo the revision surgery again in retrospect.

CONCLUSION

Occult infections occur in 40% of patients who undergo anterior revision surgery for ACDF pseudoarthrosis. Albeit in a small cohort of patients, this study shows that anterior revision surgery may not result in relevant clinical improvements for patients, despite achieving fusion in 80% of cases.

LEVEL OF EVIDENCE

Retrospective study, level III.

Does screw length for primary two-level ACDF influence pseudarthrosis risk?

BACKGROUND CONTEXT

Pseudarthrosis remains a major complication for patients undergoing anterior cervical discectomy and fusion (ACDF; 0%-15% at 1-year follow-up). Potentially modifiable risk factors are known in literature, such as smoking and osteoporosis. Biomechanical studies suggest that plates with locking screws can enhance the fixation rigidity and pull-out strength. Although longer screws are known to be correlated with increased pull-out strength, deeper screw depths can increase the risk for intraoperative complications. An important factor that has yet to be studied is the minimum screw length relative to the diameter of the vertebral body (VB) necessary to achieve successful fusion. In this study, we hypothesize that screws with shorter depths relative to the VB will increase the risk for radiographic pseudarthrosis and result in poor patient reported outcomes (PROs).

PURPOSE

To examine the impact of ACDF screw length on pseudarthrosis risk.

STUDY DESIGN

A review of prospectively collected data.

PATIENT SAMPLE

A total of 85 patients were included in this study. The mean age ±standard deviation was 58.9±10.3 and 42.4% of patients were female. The mean follow-up was 21.6±8.3 months.

OUTCOME MEASURES

The neck disability index (NDI) was used to assess PROs up to 2-years after surgery. For each ACDF level, the screw length and VB% (screw length divided by the anterior-posterior VB diameter) were measured. Radiographic pseudarthrosis (interspinous motion [ISM] ≥1 mm) was recorded at 6-weeks, 6-months, and 1-year for each patient. The positive and negative predictive values (PPV, NPV) for ISM ≥ 1mm were measured for different VB% thresholds. A VB% of <75% was found to have the highest PPV (93%) and NPV (70%) for radiographic pseudarthrosis. This threshold of <75% was then assessed in our bivariate and multivariate analyses.

METHODS

We reviewed a database (2015-2018) of adult (≥18 years old) patients who underwent a primary two-level ACDF with or without corpectomy. All ACDF constructs involved fixed angle screws. The minimum follow-up period was 1 year. Multivariate analyses were performed to determine if screw VB% was an independent risk factor for radiographic pseudarthrosis.

RESULTS

By 1-year, overall fusion success was achieved in 92.9% of patients. The 1-year revision rate was 4.7%. Patients with any screw VB% <75% had substantially worse fusion success (64.3%) than those who did not (98.6%) at 1-year. The VB% <75% increased the risk for radiographic pseudarthrosis at every follow up period. In comparison to other time-points, patients with radiographic pseudarthrosis at 6 weeks had significantly worse NDI scores by 2-years (p=.047). The independent risk factors for radiographic pseudarthrosis at 6-weeks included any screw VB% <75% (OR 77, p<.001), prior/current smoker (OR 6.8, p=.024), and corpectomy (OR 0.1, p=.010). Patients with ISM≥1 mm had a higher rate of revision surgery at 1-year (5.9% vs. 3.9%), but this was not statistically significant (p=.656).

CONCLUSIONS

In primary two-level ACDF, VB% <75% is significantly associated with increased ISM (≥1 mm) at all time points for this study. As an intraoperative guide, spine surgeons can use the screw VB% threshold of <75% to avoid unnecessarily short screws. This threshold can be easily measured pre- and intraoperatively, and has been found to be strongly correlated to radiographic pseudarthrosis in the early postoperative period.

Comparison between repeat anterior and posterior decompression and fusion in the treatment of two-level symptomatic adjacent segment disease after anterior cervical arthrodesis

BACKGROUND

Two-level symptomatic adjacent segment disease (ASD) is rarely reported, but remains a challenge after anterior cervical arthrodesis. The purpose of this study was to compare the clinical and radiological outcomes of repeat anterior and posterior decompression and fusion procedures for two-level symptomatic ASD.

METHODS

Thirty-two patients with two-level symptomatic ASD were retrospectively reviewed and underwent repeat anterior cervical discectomy and fusion (ACDF) or posterior decompression and fusion (PDF). Clinical outcomes (JOA, NDI, and VAS scores), perioperative parameters (blood loss, operation time, and length of hospital stay), radiological parameters (cervical lordosis and ROM), and complications were compared.

RESULTS

Eighteen patients underwent ACDF, and 14 patients underwent PDF. Patients who underwent PDF were older, more frequently presented with myelopathic deficits, and were fused at more levels. Patients who underwent ACDF experienced significantly shorter surgery time (p < 0.001), lower blood loss (p < 0.001), and reduced hospital stay (p = 0.002). Both groups exhibited significant increases in JOA scores and decreases in NDI and both neck pain and arm pain VAS scores (p < 0.05), but patients who underwent PDF had significantly higher NDI scores (p = 0.012), neck pain VAS scores (p = 0.019), loss of cervical lordosis (p < 0.001), and loss of ROM (p = 0.001). Three patients developed dysphagia in the ACDF group, and two patients had C5 root palsy and one had hematoma in the PDF group. Recurrent ASD after the second operation occurred in two patients in the ACDF group but no patients in the PDF group.

CONCLUSIONS

For patients with two-level symptomatic ASD, both anterior and posterior decompression and fusion were effective for improving the neurological function. For patients with radicular symptoms, ACDF had less surgical trauma, better restoration of lordosis, and less postoperative neck pain, but higher chance of recurrent ASD. PDF was an effective surgical option for older patients with myelopathy developing in adjacent segments.

Outcomes of Revision Surgery for Pseudarthrosis After Anterior Cervical Fusion: Case Series and Systematic Review

STUDY DESIGN

Case series/systematic review.

OBJECTIVES

To report on patients undergoing posterior cervical fusion for symptomatic pseudarthrosis following anterior cervical discectomy and fusion (ACDF), and to assess outcomes reporting in the literature.

METHODS

Patients undergoing posterior instrumented fusion for pseudarthrosis after primary ACDF from 2013 to 2018 by a single surgeon were reviewed consecutively. Neck Disability Index (NDI) and visual analogue scale (VAS) arm/neck were recorded at preoperative, 6-month, and 1-year time points. A systematic review of the literature was performed, and outcomes reporting was recorded.

RESULTS

NDI scores were 54.4 (SD 19.1), 36.6 (SD 18.1), and 41.2 (SD 19.2) at preoperative, 6-month, and 1-year time points, respectively, with improvement from preoperatively to 6 months (P = .004). VAS neck scores were 8.1 (SD 1.3), 5.0 (SD 2.9), and 5.8 (SD 2.2) at preoperative, 6-month, and 1-year time points, respectively, with improvement from preoperatively to 6 months (P = .038). VAS arm scores were 5.1 (SD 4.1), 3.5 (SD 3.2), and 3.6 (SD 2.7) at preoperative, 6-month, and 1-year time points, respectively, with improvement although these did not reach statistical significance (P = .145). The most common subjective outcomes reported in the literature were general symptoms assessments (43%), ordinal scales (43%), and VAS neck (19%) scales, with the majority of studies (67%) documenting one measure.

CONCLUSIONS

Patient-reported outcomes demonstrate clinically meaningful improvement within the first 6 months after posterior fusion for pseudarthrosis. Studies demonstrate substantial variability and no standardization in outcomes reporting, limiting the ability to compare results across interventions and pathologies. Standardized reporting will enable comparisons to inform patients and physicians on the optimal approach to treat this difficult problem.

Complications of anterior cervical spine surgery: a systematic review of the literature

The anterior approach to the cervical spine is commonly utilized for a variety of degenerative, traumatic, neoplastic, and infectious indications. While many potential complications overlap with those of the posterior approach, the distinct anatomy of the anterior neck also presents a unique set of hazards. We performed a systematic review of the literature to assess the etiology, presentation, natural history, and management of these complications. Following the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), a PubMed search was conducted to evaluate clinical studies and case reports of patients who suffered a complication of anterior cervical spine surgery. The search specifically included articles concerning adult human subjects, written in the English language, and published from 1989 to 2019. The PubMed search yielded 240 articles meeting our criteria. The overall rates of complications were as follows: dysphagia 5.3%, esophageal perforation 0.2%, recurrent laryngeal nerve palsy 1.3%, infection 1.2%, adjacent segment disease 8.1%, pseudarthrosis 2.0%, graft or hardware failure 2.1%, cerebrospinal fluid leak 0.5%, hematoma 1.0%, Horner syndrome 0.4%, C5 palsy 3.0%, vertebral artery injury 0.4%, and new or worsening neurological deficit 0.5%. Morbidity rates in anterior cervical spine surgery are low. Nevertheless, the unique anatomy of the anterior neck presents a wide variety of potential complications involving vascular, aerodigestive, neural, and osseous structures.

Comparing the 5-Year Health State Utility Value of Cervical Disc Replacement and Anterior Cervical Discectomy and Fusion

STUDY DESIGN

Health utility analysis.

OBJECTIVES

To determine the health state utility (HSU) of 1- and 2-level anterior cervical discectomy and fusion (ACDF) and cervical disc replacement (CDR).

METHODS

Data from the Medtronic Prestige Cervical Disc investigational device exemption studies was used. Four groups were defined: 1-level ACDF, 1-level CDR, 2-level ACDF, and 2-level CDR. The 36-item Short Form Health Survey (SF-36) was collected at baseline, 12 months, 24 months, 36 months, and 60 months postoperatively and converted into utility scores for each time point. A repeated-measures 1-way analysis of variance (ANOVA) was used to detect differences among groups. Tukey's method for multiple comparisons was used to determine which means within the groups were statistically different (P < .05).

RESULTS

We found a statistically significant difference in HSU among groups as determined by repeated-measures 1-way ANOVA (P = .0008). Post hoc analysis indicated that 1-level ACDF had a statistically lower utility score compared with 1- and 2-level CDR (P = .04 and P = .02, respectively). Similarly, 2-level ACDF had lower utility values compared with 2-level CDR (P = .010). One-level ACDF utility values were not different from 2-level ACDF values (P = .55). Similarly, 1-level CDR and 2-level CDR did not have different utility values (P = .67).

CONCLUSIONS

Overall, CDR had higher health state utility scores for 1- and 2-level procedures at every time point. This study indicates that CDR results in a higher postoperative health utility state than ACDF, and may therefore be an effective alternative to ACDF for treating degenerative conditions of the cervical spine.

Bone SPECT/CT in the postoperative spine: a focus on spinal fusion

Low back pain is a global problem affecting one in 10 people. The management of low back pain varies from conservative to more invasive methods with a spectacular increase in the number of patients undergoing spinal fusion surgery during the last decade. Conventional radiological and radionuclide studies are often used in the assessment of persistent or recurring pain after spinal surgery with several advantages and limitations related to each technique. This article reviews the key contribution of integrated bone SPECT/CT in evaluating patients with persistent or recurring pain after spinal surgery, focusing on spinal fusion. Current literature supports the use of bone SPECT/CT as an adjunct imaging modality and problem-solving tool in evaluating patients with suspicion of pseudarthrosis, adjacent segment degeneration, and hardware failure. The role of bone SPECT/CT in post-operative orthopaedic scenarios is evolving, and this review highlights the need for further research on the role of bone SPECT/CT in these patients.

Indications for Direct Laryngoscopic Examination of Vocal Cord Function Prior to Anterior Cervical Surgery

Recurrent laryngeal nerve palsy (RLNP) is among the most common complications in both thyroid surgeries and anterior approaches to the cervical spine, having both a diverse etiology and presentation. Most bilateral paresis, with subsequent devastating impact on patients, are due to failure to recognize unilateral recurrent laryngeal nerve paralysis and, although rare, are entirely preventable with appropriate history and screening. Recurrent laryngeal nerve palsy has been shown to present asymptomatically in as high as 32% of cases, which yields limitations on exclusively screening with physical examination. Based on the available literature, diagnosis of unilateral RLNP is the critical factor in preventing the occurrence of bilateral RLNP as the surgeon may elect to operate on the injured side to prevent bilateral paresis. Analysis of incidence rates shows postoperative development of unilateral RLNP is 13.1 (95% confidence interval [CI]: 6.1-28.1) and 13.90 (95% CI: 6.6-29.3) times more likely in anterior spine and thyroid surgery, respectively, in comparison with intubation. Currently, there is no consensus on when to order a preoperative laryngoscopic examination prior to anterior cervical spine surgery. The importance of patient history should be emphasized, as it is the basis for indications of preoperative laryngoscopy. Efforts to minimize postoperative complications must be made, especially when considering the rising rate of cervical fusion. This study presents a systematic review of the literature defining key causes of RLNP, with a probability-based protocol to indicate direct laryngoscopy prior to anterior cervical surgery as a screening tool in the prevention of bilateral RLNP.

Posterior Cervical Fusion Using Cervical Interfacet Spacers in Patients With Symptomatic Cervical Pseudarthrosis

BACKGROUND

Posterior cervical fusion with cervical interfacet spacer (CIS) is a novel allograft technology offering the potential to provide indirect neuroforaminal decompression while simultaneously enhancing fusion by placing the allograft in compression.

OBJECTIVE

To analyze the clinical and radiological outcomes after posterior cervical fusion with CIS in patients with symptomatic anterior cervical pseudarthroses.

METHODS

Medical records of patients who underwent posterior cervical fusion with CIS for symptomatic pseudarthrosis after anterior cervical diskectomy and fusion were reviewed. Standardized outcome measures such as visual analog scale (VAS) score for neck and arm pain, Neck Disability Index (NDI), and upright lateral cervical radiographs were reviewed.

RESULTS

There were 19 patients with symptomatic cervical pseudarthrosis. Preoperative symptoms included refractory neck or arm pain. The average follow-up was 20 months (range, 12-56 months). There was improvement in VAS score for neck pain (P < .004), radicular arm pain (P < .007), and NDI score (P < .06) after surgery, with 83%, 72%, and 67% of patients showing improvement in their VAS neck pain, VAS arm pain, and NDI scores, respectively. Fusion rate was high, with fusion occurring at all levels treated for pseudarthrosis. There was a small improvement in cervical lordosis (mean difference, 2 ± 5.17°; P = .09) and slight worsening of C2-7 sagittal vertical axis after surgery (mean difference, 1.89 ± 7.87 mm; P = .43).

CONCLUSION

CIS provides an important fusion technique, allowing placement of an allograft in compression for posterior cervical fusion in patients with anterior cervical pseudarthroses. Although there was improvement in clinical outcome measures after surgery, placement of CIS had no clinically significant impact on cervical lordosis and C2-7 sagittal vertical axis.

Reoperation Rates After Anterior Cervical Discectomy and Fusion for Cervical Spondylotic Radiculopathy and Myelopathy: A National Population-based Study

STUDY DESIGN

National population-based cohort study.

OBJECTIVE

To compare the reoperation rates between cervical spondylotic radiculopathy and myelopathy in a national population of patients.

SUMMARY OF BACKGROUND DATA

There is an inherently low incidence of reoperation after surgery for cervical degenerative disease. Therefore, it is difficult to sufficiently power studies to detect differences between reoperation rates of different cervical diagnoses. National population-based databases provide large, longitudinally followed cohorts that may help overcome this challenge.

METHODS

We used the Korean Health Insurance Review and Assessment Service national database to select our study population. We included patients with the diagnosis of cervical spondylotic radiculopathy or myelopathy who underwent anterior cervical discectomy and fusion from January 2009 to June 2014. We separated patients into two groups based on diagnosis codes: cervical spondylotic radiculopathy or cervical spondylotic myelopathy. Age, sex, presence of diabetes, osteoporosis, associated comorbidities, number of operated cervical disc levels, and hospital types were considered potential confounding factors.

RESULTS

The overall reoperation rate was 2.45%. The reoperation rate was significantly higher in patients with cervical spondylotic myelopathy than in patients with cervical radiculopathy (myelopathy: P = 0.0293, hazard ratio = 1.433, 95% confidence interval 1.037-1.981). Male sex, presence of diabetes or associated comorbidities, and hospital type were noted to be risk factors for reoperation.

CONCLUSION

The reoperation rate after anterior cervical discectomy and fusion was higher for cervical spondylotic myelopathy than for cervical spondylotic radiculopathy in a national population of patients.

LEVEL OF EVIDENCE

3.

Reoperation Rates After Surgery for Degenerative Cervical Spine Disease According to Different Surgical Procedures: National Population-based Cohort Study

STUDY DESIGN

National population-based cohort study.

OBJECTIVE

To evaluate reoperation rates of cervical spine surgery for cervical degenerative conditions utilizing a national population database.

SUMMARY OF BACKGROUND DATA

There is an inherently low incidence of reoperation after surgery for cervical degenerative disease. Therefore, it is difficult to sufficiently power studies to detect differences between reoperation rates of different cervical surgical procedures. National population-based databases provide large, longitudinally followed cohorts that may help overcome this challenge.

METHODS

We used the Korean Health Insurance Review and Assessment Service national database to select our study population. We included patients with diagnosis of cervical spondylotic radiculopathy or myelopathy who underwent cervical surgeries from January 2009 to June 2014. We separated patients into three groups based on surgical procedures: discectomy or corpectomy with anterior fusion, laminoplasty, or laminectomy with posterior fusion. Age, sex, presence of diabetes, osteoporosis, associated comorbidities, number of operated cervical disc levels, and hospital types were considered potential confounding factors. Reoperation rates were analyzed over early and late periods.

RESULTS

The reoperation rate over the entire follow-up period was 3.31%. Overall, the reoperation rate was significantly higher after laminectomy with posterior fusion or laminoplasty than after discectomy or corpectomy with anterior fusion. A similar pattern was seen during the late period. In the early period, rates were higher only after laminectomy with posterior fusion than after discectomy or corpectomy with anterior fusion. Sex, presence of diabetes, associated comorbidities, and hospital types were noted to be risk factors for reoperation.

CONCLUSION

The reoperation rate was higher after laminectomy with posterior fusion or laminoplasty. Given clinical scenarios in which either anterior or posterior approaches can be utilized, risk of reoperation can be another variable to consider in surgical planning and patient education.

LEVEL OF EVIDENCE

3.

Pseudarthrosis of the Cervical Spine: Risk Factors, Diagnosis and Management

Cervical myelopathy and radiculopathy are common pathologies that often improve with spinal decompression and fusion. Postoperative complications include pseudarthrosis, which can be challenging to diagnose and manage. We reviewed the literature with regard to risk factors, diagnosis, controversies, and management of cervical pseudarthrosis.

A new source of autograft bone for interbody fusion in anterior cervical discectomy and fusion surgery: experience in 893 cases

PURPOSE

This study is to share our experience of a modified anterior cervical discectomy and fusion (ACDF) procedure with a new source of autograft bone for interbody fusion.

METHODS

The same procedure was performed in 893 cases where autograft was obtained from the osteophytes and/or the reams of vertebrae. For each case, radiological fusion rate and clinical outcome were followed up for 3 and 12 months after surgery.

RESULTS

For one to three-level ACDF, fusion rates were from 67.8% to 75.4% at 3 months follow-up, and 92% to 98.8% at 12 months follow-up. Patients' VAS, NDI, JOA and SF-36 score improve significantly at 12 months follow-up.

CONCLUSION

Osteophytes and vertebral reams can be a reliable source of bone graft that leads to high fusion rate and successful clinical outcome while avoiding all the problems with the current bone grafting methods used in ACDF surgery.

Recurrent laryngeal nerve injury following reoperative anterior cervical discectomy and fusion: a meta-analysis

OBJECTIVE Recurrent laryngeal nerve (RLN) injury is one of the most frequent complications of anterior cervical discectomy and fusion (ACDF) procedures. The frequency of RLN is reported as 1%-11% in the literature. (4 , 15) The rate of palsy after reoperative ACDF surgery is not well defined. This meta-analysis was performed to review the current medical evidence on RLN injury after ACDF surgery and to determine a relative rate of RLN injury after reoperative ACDF. METHODS MEDLINE, PubMed, and Google Scholar searches were performed using several key words and phrases related to ACDF surgery. Included studies were written in English, addressed revisionary ACDF surgery, and studied outcomes of RLN injury. Statistical analysis was then performed using a random-effects model to calculate a pooled rate of RLN injury. The heterogeneity of the studies was assessed using Cochran's Q statistic and I(2) statistic, and a funnel plot was constructed to evaluate publication bias. RESULTS The search initially identified 345 articles on this topic. Eight clinical articles that met all inclusion criteria were included in the meta-analysis. A total of 238 patients were found to have undergone reoperative ACDF. Thirty-three of those patients experienced an RLN injury. This analysis identified a rate of RLN injury in the literature after reoperative ACDF of 14.1% (95% confidence interval [CI] 9.8%-19.1%). CONCLUSIONS The rate of RLN palsy of 14.1% was greater than any published rate of RLN injury after primary ACDF operations, suggesting that there is a greater risk of hoarseness and dysphagia with reoperative ACDF surgeries than with primary procedures as reported in these studies.

A Tunneled Subcricoid Approach for Anterior Cervical Spine Reoperation: Technical and Safety Results

OBJECTIVE

Anterior cervical spine decompression and fusion are common neurosurgical operations. Reoperation of the anterior cervical spine is associated with increased morbidity. The authors describe a novel subcricoid approach to protect the recurrent laryngeal nerve in a cuff of tissue while facilitating surgical access to the anterior cervical spine.

METHODS

Single institution, consecutive case review of 48 patients undergoing reoperation in the anterior cervical region including the level of C5 and below. Univariable and multivariable regression analysis was used to determine predictors of postoperative morbidity.

RESULTS

No intraoperative complications were reported. Estimated blood loss for the approach was 13.6 ± 3.1 mL. Nine of 48 patients developed immediate postoperative complications, including vocal cord paresis (10.4%), moderate-to-severe dysphagia (10.4%), and neck edema requiring intubation (2.1%). No postoperative hematomas or death occurred. All complications occurred with 4 or more levels of exposure (1-3 disc levels, 0%, vs. ≥ 4 disc levels, 31%). Extension of the exposure to the upper thoracic spine was associated with odds for postoperative complications (adjusted odds ratio, 6.50; 95% confidence interval, 1.14-37.03) and prolonged hospital stay (adjusted increase 4.23 days, P < 0.01).

CONCLUSION

The tunneled subcricoid approach is a relatively safe corridor to reapproach the anterior cervical spine at the level of C5 and below. However, caution must be exercised when using this approach to expose 4 or more disc levels and with extension of the exposure to the upper thoracic spine. Future comparative studies are needed to establish patient selection criteria in determining the use of this technique compared with classic approaches.

Radiological Determination of Postoperative Cervical Fusion: A Systematic Review

STUDY DESIGN

Systematic review.

OBJECTIVE

To determine best criteria for radiological determination of postoperative subaxial cervical fusion to be applied to current clinical practice and ongoing future research assessing fusion to standardize assessment and improve comparability.

SUMMARY OF BACKGROUND DATA

Despite availability of multiple imaging modalities and criteria, there remains no method of determining cervical fusion with absolute certainty, nor clear consensus on specific criteria to be applied.

METHODS

A systematic search in MEDLINE/Cochrane Collaboration Library (through March 2014). Included studies assessed C2 to C7 via anterior or posterior approach, at 12 weeks or more postoperative, with any graft or implant. Overall body of evidence with respect to 6 posited key questions was determined using Grading of Recommendations Assessment, Development and Evaluation and Agency for Healthcare Research and Quality precepts.

RESULTS

Of plain radiographical modalities, there is moderate evidence that the interspinous process motion method (<1 mm) is more accurate than the Cobb angle method for assessing anterior cervical fusion. Of the advanced imaging modalities, there is moderate evidence that computed tomography (CT) is more accurate and reliable than magnetic resonance imaging in assessing anterior cervical fusion. There is insufficient evidence regarding the optimal modality and criteria for assessing posterior cervical fusions and insufficient evidence to support a single time point after surgery as being optimal for determining fusion, although some evidence suggest that reliability of radiography and CT improves with increasing time postoperatively.

CONCLUSION

We recommend using less than 1-mm motion as the initial modality for determining anterior cervical arthrodesis for both clinical and research applications. If further imaging is needed because of indeterminate radiographical evaluation, we recommend CT, which has relatively high accuracy and reliability, but due to greater radiation exposure and cost, it is not routinely suggested. We recommend that plain radiographs also be the initial method of determining posterior cervical fusion but suggest a lower threshold for obtaining CT scans because dynamic radiographs may not be as useful if spinous processes have been removed by laminectomy.

LEVEL OF EVIDENCE

1.

Soft-tissue reconstruction after total en bloc sacrectomy

OBJECT

Total en bloc sacrectomy is a dramatic procedure that results in extensive sacral defects. The authors present a series of patients who underwent flap reconstruction after total sacrectomy, report clinical outcomes, and provide a treatment algorithm to guide surgical care of this unique patient population.

METHODS

After institutional review board approval, data were collected for all patients who underwent total sacrectomy between 2002 and 2012 at The Johns Hopkins Hospital. Variables included demographic data, medical history, tumor characteristics, surgical details, postoperative complications, and clinical outcomes. All subtotal sacrectomies were excluded.

RESULTS

Between 2002 and 2012, 9 patients underwent total sacrectomy with flap reconstruction. Diagnoses included chordoma (n = 5), osteoblastoma (n = 1), sarcoma (n = 2), and metastatic colon cancer (n = 1). Six patients received gluteus maximus (GM) flaps with a prosthetic rectal sling following a single-stage, posterior sacrectomy. Four required additional paraspinous muscle (PSM) or pedicled latissimus dorsi (LD) fasciocutaneous flaps. Three patients underwent multistage sacrectomy with an anterior-posterior approach, 2 of whom received pedicled vertical rectus abdominis myocutaneous (VRAM) flaps, and 1 of whom received local GM, LD, and PSM flaps. Flap complications included dehiscence (n = 4) and infection (n = 1). During the 1st year of follow-up, 2 of 9 patients (22%) were able to ambulate with an assistive device by the 1st postoperative month, and 6 of 9 (67%) were ambulatory with a walker by the 3rd postoperative month. By postoperative Month 12, 5 of 9 patients (56%)—or 5 of 5 patients not lost to follow-up (100%)—were able to able to ambulate independently.

CONCLUSIONS

The authors' experience suggests that the GM and pedicled VRAM flaps are reliable options for softtissue reconstruction of total sacrectomy defects. For posterior-only operations, GM flaps with or without a prosthetic rectal sling are generally used. For multistage operations including a laparotomy, the authors consider the pedicled VRAM flap to be the gold standard for simultaneous reconstruction of the pelvic diaphragm and obliteration of dead space.

A Meta-Analysis of the Clinical and Fusion Results following Treatment of Symptomatic Cervical Pseudarthrosis

Study Design Systematic literature review and meta-analysis. Objective This study is a meta-analysis assessing the fusion rate and the clinical outcomes of cervical pseudarthrosis treated with either a posterior or a revision anterior approach. Methods A literature search of PubMed, Cochrane, and Embase was performed. Variables of interest included fusion rate and clinical success. The effect size based on logit event rate was calculated from the pooled results. The studies were weighted by the inverse of the variance, which included both within- and between-study error. The confidence intervals were reported at 95%. Heterogeneity was assessed using the Q statistic and I (2), where I (2) is the estimate of the percentage of error due to between-study variation. Results Sixteen studies reported fusion outcomes; 10 studies reported anterior and/or posterior results. The pooled fusion success was 86.4% in the anterior group and 97.1% in the posterior group (p = 0.028). The anterior group demonstrated significant heterogeneity with Q value of 34.2 and I (2) value of 73.7%; no heterogeneity was seen in the posterior group. The clinical outcomes were reported in 10 studies, with eight reporting results of anterior and posterior approaches. The pooled clinical success rate was 77.0% for anterior and 71.7% for posterior (p = 0.55) approaches. There was significant heterogeneity in both groups (I (2) 16.1; 19.2). Conclusions Symptomatic cervical pseudarthrosis can be effectively managed with either an anterior or a posterior approach. The posterior approach demonstrates a significantly greater fusion rate compared with the anterior approach, though the clinical outcome does not differ between the two groups.

Revision surgery for failed cervical spine reconstruction: review article

BACKGROUND

As the number of cervical spine procedures performed continues to increase, the need for revision surgery is also likely to increase. Surgeons need to understand the etiology of post-surgical changes, as well as have a treatment algorithm when evaluating these complex patients.

QUESTIONS/PURPOSES

This study aims to review the rates and etiology of revision cervical spine surgery as well as describe our treatment algorithm.

METHODS

We used a narrative and literature review. We performed a MEDLINE (PubMed) search for "cervical" and "spine" and "revision" which returned 353 articles from 1993 through January 22, 2014. Abstracts were analyzed for relevance and 32 articles were reviewed.

RESULTS

The rates of revision surgery on the cervical spine vary by the type and extent of procedure performed. Patient evaluation should include a detailed history and review of the indication for the index procedure, as well as lab work to rule out infection. Imaging studies including flexion/extension radiographs and computed tomography are obtained to evaluate potential pseudarthrosis. Magnetic resonance imaging is helpful to evaluate the disc, neural elements, soft tissue, and to differentiate scar from infection. Sagittal alignment should be corrected if necessary.

CONCLUSIONS

Recurrent or new symptoms after cervical spine reconstruction can be effectively treated with revision surgery after identifying the etiology, and completing the appropriate workup.

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

STUDY DESIGN

Human cadaveric biomechanical analysis.

OBJECTIVE

To investigate the effect on cervical spine segmental stability that results from a posterior foraminotomy after cervical disc arthroplasty (CDA).

SUMMARY OF BACKGROUND DATA

Posterior foraminotomy offers the ability to decompress cervical nerves roots while avoiding the need to extend a previous fusion or revise an arthroplasty to a fusion. However, the safety of a foraminotomy in the setting of CDA is unknown.

METHODS

Segmental nondestructive range of motion (ROM) was analyzed in 9 human cadaveric cervical spine specimens. After intact testing, each specimen was sequentially tested according to the following 4 experimental groups: group 1=C5-C6 CDA, group 2=C5-C6 CDA with unilateral C5-C6 foraminotomy, group 3=C5-C6 CDA with bilateral C5-C6 foraminotomy, and group 4=C5-C6 CDA with C5-C6 and C4-C5 bilateral foraminotomy.

RESULTS

No differences in ROM were found between the intact, CDA, and foraminotomy specimens at C4-C5 or C6-C7. There was a step-wise increase in C5-C6 axial rotation from the intact state (8°) to group 4 (12°), although the difference did not reach statistical significance. At C5-C6, the degree of lateral bending remained relatively constant. Flexion and extension at C5-C6 was significantly higher in the foraminotomy specimens, groups 2 (18.1°), 3 (18.6°), and 4 (18.2°), compared with the intact state, 11.2°. However, no ROM difference was found within foraminotomy groups (2-4) or between the foraminotomy groups and the CDA group (group 1), 15.3°.

CONCLUSION

Our results indicate that cervical stability is not significantly decreased by the presence, number, or level of posterior foraminotomies in the setting of CDA. The addition of foraminotomies to specimens with a pre-existing CDA resulted in small and insignificant increases in segmental ROM. Therefore, biomechanically, posterior foraminotomy/foraminotomies may be considered a safe and viable option in the setting of recurrent or adjacent level radiculopathy after cervical disc replacement.

LEVEL OF EVIDENCE

N/A.

Does smoking have an impact on fusion rate in single-level anterior cervical discectomy and fusion with allograft and rigid plate fixation?

Object

Although smoking has been shown to negatively affect fusion rates in patients undergoing multilevel fusions of the cervical and lumbar spine, the effect of smoking on fusion rates in patients undergoing single-level anterior cervical discectomy and fusion (ACDF) with allograft and plate fixation has yet to be thoroughly investigated. The objective of the present study was to address the effect of smoking on fusion rates in patients undergoing a 1-level ACDF with allograft and a locked anterior cervical plate.

Methods

This study is composed of patients from the control groups of 5 separate studies evaluating the use of an anterior cervical disc replacement to treat cervical radiculopathy. For each of the 5 studies the control group consisted of patients who underwent a 1-level ACDF with allograft and a locked cervical plate. The authors of the present study reviewed data obtained in a total of 573 patients; 156 patients were smokers and 417 were nonsmokers. A minimum follow-up period of 24 months was required for inclusion in this study. Fusion status was assessed by independent observers using lateral, neutral, and flexion/extension radiographs.

Results

An overall fusion rate of 91.4% was achieved in all 573 patients. A solid fusion was shown in 382 patients (91.6%) who were nonsmokers. Among patients who were smokers, 142 (91.0%) had radiographic evidence of a solid fusion. A 2-tailed Fisher exact test revealed a p value of 0.867, indicating no difference in the union rates between smokers and nonsmokers.

Conclusions

The authors found no statistically significant difference in fusion status between smokers and nonsmokers who underwent a single-level ACDF with allograft and a locked anterior cervical plate. Although the authors do not promote tobacco use, it appears that the use of allograft with a locked cervical plate in single-level ACDF among smokers produces similar fusion rates as it does in their nonsmoking counterparts.

Prospective randomized study of cervical arthroplasty and anterior cervical discectomy and fusion with long-term follow-up: results in 74 patients from a single site

Object

The purpose of this study was to evaluate the long-term results of cervical total disc replacement (TDR) and anterior cervical discectomy and fusion (ACDF) in the treatment of single-level cervical radiculopathy.

Methods

The results of 2 separate prospective, randomized, US FDA Investigational Device Exemption pivotal trials (Bryan Disc and Kineflex|C) from a single investigational site were combined to evaluate outcomes at long-term follow-up. The primary clinical outcome measures included the Neck Disability Index (NDI), visual analog scale (VAS), and neurological examination. Patients were randomized to receive cervical TDR in 2 separate prospective, randomized studies using the Bryan Disc or Kineflex|C cervical artificial disc compared with ACDF using structural allograft and an anterior plate. Patients were evaluated preoperatively; at 6 weeks; at 3, 6, and 12 months; and then yearly for a minimum of 48 months. Plain radiographs were obtained at each study visit.

Results

A total of 74 patients were enrolled and randomly assigned to either the cervical TDR (n = 41) or ACDF (n = 33) group. A total of 63 patients (86%) completed a minimum of 4 years follow-up. Average follow-up was 6 years (72 months) with a range from 48 to 108 months. In both the cervical TDR and ACDF groups, mean NDI scores improved significantly by 6 weeks after surgery and remained significantly improved throughout the minimum 48-month follow-up (p < 0.001). Similarly, the median VAS pain scores improved significantly by 6 weeks and remained significantly improved throughout the minimum 48-month follow-up (p < 0.001). There were no significant differences between groups in mean NDI or median VAS scores. The range of motion (ROM) in the cervical TDR group remained significantly greater than the preoperative mean, whereas the ROM in the ACDF group was significantly reduced from the preoperative mean. There was significantly greater ROM in the cervical TDR group compared with the ACDF group. There were 3 reoperations (7.3%) at index or adjacent levels in the cervical TDR group; all were cervical laminoforaminotomies. There were 2 adjacent-level reoperations in the cervical TDR group (4.9%). There was 1 reoperation (3.0%) in the ACDF group at an index or adjacent level (a second ACDF at the adjacent level). There was no statistically significant difference in overall reoperation rate or adjacent-level reoperation rate between groups.

Conclusions

Both cervical TDR and ACDF groups showed excellent clinical outcomes that were maintained over long-term follow-up. Both groups showed low index-level and adjacent-level reoperation rates. Both cervical TDR and ACDF appear to be viable options for the treatment of single-level cervical radiculopathy.

Comparative study of clinical outcomes of anterior cervical discectomy and fusion using autobone graft or cage with bone substitute

Study Design

A retrospective study.

Purpose

To compare the clinical and radiological outcomes of autogenous bone graft and cage with bone substitute for anterior cervical discectomy and fusion.

Overview of Literature

The clinical outcomes of cage with bone substitute for anterior cervical discectomy and fusion is satisfactory.

Methods

Eighty four patients who underwent cervical spine surgery between February 2004 and April 2009 were included. Fifty-nine patients were approached anteriorly and underwent anterior cervical discectomy and fusion by the Smith-Robinson method (Group A), and 25 patients underwent fusion by decompression of the cervical spine and cage with bone substitute (Group B). We measured and evaluated the postoperative period until patients were able to ambulate, for pre- and postoperative symptomatic improvement, postoperative complications, pre- and postoperative change of lordosis, degree of endplate collapse or subsidence, and fusion rate and period of union.

Results

By Robinson's criteria, respectively 45, 10 and 4 patients in Group A experienced excellent, good and fair symptomatic improvement, and respectively 19, 5 and 1 patients in Group B experienced excellent, good and fair symptomatic improvement. The postoperative period in which patients became ambulant and the period of hospital stay was significantly shorter in Group B. Increase of lordosis at final follow up after surgery was significantly larger in Group A, as was the fusion period. Significantly more endplate collapse occurred in Group B.

Conclusions

Of patients who had anterior cervical discectomy and fusion, results of both groups were both satisfactory.

Multidirectional flexibility of the spine following posterior decompressive surgery after single-level cervical disc arthroplasty: an in vitro biomechanical investigation

STUDY DESIGN

In vitro human cadaveric biomechanical study.

OBJECTIVE

This study quantifies the multidirectional flexibility of the spine following laminoplasty and laminectomy after cervical disc arthroplasty.

SUMMARY OF BACKGROUND DATA

Posterior decompressive surgery may be used to treat recurrence of myeloradiculopathy following disc arthroplasty. This is the first study investigating the biomechanical effects of posterior decompressive surgery combined with cervical disc arthroplasty.

METHODS

Seven human cervical spines were biomechanically evaluated under the following conditions: (1) intact; (2) discectomy (C5-C6); (3) disc arthroplasty (C5-C6); (4) arthroplasty + 3-level laminoplasty (C3-C5); (5) arthroplasty + 4-level laminoplasty (C3-C6); (6) arthroplasty + 5-level laminoplasty (C3-C7); (7) arthroplasty + 5-level laminoplasty (C3-C7) without hydroxyapatite spacers; and (8) arthroplasty + laminectomy (C3-C7). Multidirectional flexibility testing used unconstrained pure moments of ±2 Nm for flexion-extension, axial rotation, and lateral bending. Quantification of C5-C6 and C3-C7 range of motion (ROM) and neutral zone (NZ) were normalized to the intact spine (100%).

RESULTS

Flexion-extension loading of the discectomy condition demonstrated ROM of 22.05° ± 4.17° at the operative level (P < 0.05). Implantation of the porous coated motion device restored segmental motion near the intact condition (ROM, 9.97° ± 6.44°; NZ, 5.82° ± 6.18°). There were no statistical differences between 3-level (13.79° ± 6.49°), 4-level (14.51° ± 5.76°), and 5-level (15.67° ± 5.71°) laminoplasty; however, additional levels demonstrated a trend toward increased motion at the arthroplasty level. Laminoplasty without spacers (17.45°) and laminectomy (18.27°) indicated even greater segmental motion (P > 0.05). Axial rotation and lateral bending indicated trends similar to those for flexion-extension.

CONCLUSION

Posterior decompressive surgery increased ROM and NZ in all loading modes compared to arthroplasty alone, and laminectomy markedly increased motion compared with laminoplasty. Use of hydroxyapatite spacers and minimization of the extent of laminoplasty appear to be biomechanically favorable in this in vitro model.

Management of anterior cervical pseudarthrosis

Object

The objective of this systematic review was to use evidence-based medicine to identify the best methodology for diagnosis and treatment of anterior pseudarthrosis.

Methods

The National Library of Medicine and Cochrane Database were queried using MeSH headings and key words relevant to pseudarthrosis and cervical spine surgery. Abstracts were reviewed, after which studies meeting inclusion criteria were selected. The guidelines group assembled an evidentiary table summarizing the quality of evidence (Classes I–III). Disagreements regarding the level of evidence were resolved through an expert consensus conference. The group formulated recommendations that contained the degree of strength based on the Scottish Intercollegiate Guidelines network. Validation was done through peer review by the Joint Guidelines Committee of the American Association of Neurological Surgeons/Congress of Neurological Surgeons.

Results

Evaluation for pseudarthrosis is warranted, as there may be an association between clinical outcome and pseudarthrosis. The strength of this association cannot be accurately determined because of the variable incidence of symptomatic and asymptomatic pseudarthroses (Class III). Revision of a symptomatic pseudarthrosis may be considered because arthrodesis is associated with improved clinical outcome (Class III). Both posterior and anterior approaches have proven successful for surgical correction of an anterior pseudarthrosis. Posterior approaches may be associated with higher fusion rates following repair of an anterior pseudarthrosis (Class III).

Conclusions

If suspected, pseudarthrosis should be investigated because there may be an association between arthrodesis and outcome. However, the strength of this association cannot be accurately determined. Anterior and posterior approaches have been successful.

Pseudarthrosis of the spine

Pseudarthrosis is the result of failed attempted spinal fusion. This condition typically manifests with axial or radicular pain months to years after the index operation. Diagnosis is based on clinical presentation and imaging studies, after other causes of persistent pain are ruled out. The degree of motion seen on flexion-extension radiographs that is indicative of solid or failed fusion remains a point of controversy. Thin-cut CT scans may be more reliable than radiographs in demonstrating fusion. Metabolic factors, patient factors, use and choice of instrumentation, fusion material, and surgical technique have all been shown to influence the rate of successful fusion. Treatment of the patient with symptomatic pseudarthrosis involves a second attempt at fusion and may require an approach different from that of the index surgery as well as the use of additional instrumentation, bone graft, and osteobiologic agents.

Radiographic assessment of cervical subaxial fusion

Object

The objective of this systematic review was to use evidence-based medicine to identify the best methodology for radiographic assessment of cervical subaxial fusion.

Methods

The National Library of Medicine and Cochrane Database were queried using MeSH headings and keywords relevant to cervical fusion. Abstracts were reviewed and studies meeting inclusion criteria were selected. The guidelines group assembled an evidentiary table summarizing the quality of evidence (Classes I–III). Disagreements regarding the level of evidence were resolved through an expert consensus conference. The group formulated recommendations that contained the degree of strength based on the Scottish Intercollegiate Guidelines network. Validation was done through peer review by the Joint Guidelines Committee of the American Association of Neurological Surgeons/Congress of Neurological Surgeons.

Results

Pseudarthrosis is best assessed through the absence of motion detected between the spinous processes on dynamic radiographs (Class II). The measurement of interspinous distance on dynamic radiographs of ≥ 2 mm is a more reliable indicator for pseudarthrosis than angular motion of 2° based on Cobb angle measurements (Class II). Similarly, it is also understood that the pseudarthrosis rate will increase as the threshold for allowable motion on dynamic radiographs decreases. The combination of interspinous distance measurements and identification of bone trabeculation is unreliable when performed by the treating surgeon (Class II). Identification of bone trabeculation on static radiographs should be considered a less reliable indicator of cervical arthrodesis than dynamic films (Class III).

Conclusions

Consideration should be given to dynamic radiographs and interspinous distance when assessing for pseudarthrosis.

A retrospective study of multiple interbody grafting and long segment strut grafting following multilevel anterior cervical decompression

A retrospective study of 201 patients who underwent multilevel anterior cervical decompression and fusion by multiple interbody grafting and long segment strut grafting without plate fixation was conducted from January 1991 to December 2001. Previous studies have reported lower fusion rates for anterior cervical decompressions reconstructed with multiple interbody grafts as opposed to a single long strut graft. Our aim was a retrospective study of two fusion techniques with reference to radiological and clinical outcomes in patients operated by the senior author. Of 132 patients who underwent strut grafting, 124 achieved solid fusion (93.9%), whereas 48 of 69 patients who underwent multiple interbody grafting (69.6%) achieved solid fusion. There were five cases of graft displacement or extrusion among strut-grafted patients and one among patients with interbody grafts. More 'good' and 'excellent' clinical outcomes were found among patients who underwent strut grafting (87.1 v. 81.1%). Patients with pseudoarthrosis had significantly poorer clinical outcomes. Therefore, corpectomy or vertebrectomy and strut grafting should be considered after multilevel anterior cervical decompression to increase the likelihood of successful fusion and to improve clinical outcome.

Long-term follow-up results in patients with cervical disk disease treated by cervical anterior fusion using titanium cage implants

This study is a retrospective analysis of 146 patients, 85 males and 61 females aged 21-80 years (mean 52 years), with cervical disk disease who underwent anterior fusion and titanium cage implantation with follow-up periods of no less than 72 months after surgery. All patients underwent the conventional anterior cervical approach. After removing the protruded disk and osteophyte, cylindrical titanium cages were placed. Single, two, and three level fusion was performed in 76 (52%), 64 (44%), and 6 (4%) patients, respectively. Functional assessment used the Neurosurgical Cervical Spine Scale (NCSS). The curvature index and range of motion were evaluated pre- and postoperatively. The clinical outcomes were satisfactory and there were no significant complications. The mean NCSS was 9.7 before and 12.7 at 1 year after the operation, and 12.1 at final examination. No postoperative cage extrusion or pseudoarthrosis occurred, but the cages descended in 10 patients (7%) although alignment was satisfactory. At 5 years after the operation, 140 of the 146 patients (96%) had solid fusion. The long-term results of anterior fusion with titanium cage implantation in patients with cervical disk disease were satisfactory. Titanium cage placement is a highly useful alternative to the conventional treatment method in these patients.

Preoperative functional assessment of the recurrent laryngeal nerve in patients with cervical vertebra fracture: case report

OBJECTIVE

Injury to the recurrent laryngeal nerve may occur during surgical intervention to the anterior part of the neck. However, some disorders can lead to damage to the recurrent laryngeal nerve before surgery. We report 2 cases of lower cervical vertebra fracture, leading to 1-sided injury of the recurrent laryngeal nerve.

CLINICAL PRESENTATION

One man and 1 woman with neck injuries were admitted to our hospital. The man had a C7-T1 dislocation fracture, and the woman had a C6-C7 dislocation fracture. Both patients had similar fractures and similar clinical presentations. The distinctive feature of these cases is that both patients had dysphonia after the initial injuries but before surgery.

INTERVENTION

Both patients were treated surgically, and anterior and posterior cervical stabilization was performed. During surgical intervention to the anterior part of the neck for cervical fixation, the injured side (where the vocal cords did not move during an indirect laryngoscopy) was preferred.

CONCLUSION

Patients with a cervical vertebra fracture with dysphonia and hoarseness should be examined for vocal cord dysfunction. Surgical intervention should be performed on the side of the injured recurrent laryngeal nerve.

Minimally invasive cervical microendoscopic laminoforaminotomy

Spine surgery has seen parallel interest and development in the areas of motion preservation and minimally invasive surgery. Posterior microendoscopic laminoforaminotomy (MELF) allows for neural decompression while maintaining motion via a minimally invasive approach. This technique shares the advantage of maintenance of motion with arthroplasty, but without the need for instrumentation. Therefore, the procedure is motion preserving, minimally invasive and cost-effective. The ideal indications for posterior MELF include unilateral radiculopathy secondary to "hard disc" or spondylosis, as well as soft disc herniations. The authors present a modified surgical technique for posterior MELF as well as a case study illustrating its synergy with anterior arthroplasty.

Diagnosing cervical fusion: a comprehensive literature review

Study Design

Comprehensive literature review.

Purpose

To document the criteria for fusion utilized in these studies to determine if a consensus on the definition of a solid fusion exists.

Overview of Literature

Numerous studies have reported on fusion rates following anterior cervical arthrodesis. There is a wide discrepancy in the fusion rates in these studies. While factors such as graft type, Instrumentation, and technique play a factor in fusion rate, another reason for the difference may be a result of differences in the definition of fusion following anterior cervical spine surgery.

Methods

A comprehensive English Medline literature review from 1966 to 2004 using the key words "anterior," "cervical," and "fusion" was performed. We divided these into two groups: newer studies done between 2000 and 2004, and earlier studies done between 1966 and 2000. These articles were then analyzed for the number of patients, follow-up period, graft type, and levels fused. Moreover, all of the articles were examined for their definition of fusion along with their fusion rate.

Results

In the earlier studies from 1966 to 2000, there was no consensus for what constituted a solid fusion. Only fifteen percent of these studies employed the most stringent definition of a solid fusion which was the presence of bridging bone and the absence of motion on flexion and extension radiographs. On the other hand, the later studies (2000 to 2004) used such a definition a majority (63%) of the time, suggesting that a consensus opinion for the definition of fusion is beginning to form.

Conclusions

Our study suggests that over the past several years, a consensus definition of fusion is beginning to form. However, a large percentage of studies are still being published without using stringent fusion criteria. To that end, we recommend that all studies reporting on fusion rates use the most stringent criteria for solid fusion following anterior cervical spine surgery: the absence of motion on flexion/extension views and presence of bridging trabeculae on lateral x-rays. We believe that a universal adoption of such uniform criteria will help to standardize such studies and make it more possible to compare one study with another.

Three-level anterior cervical discectomy and fusion in elderly patients with wedge shaped tricortical autologous graft: A consecutive prospective series

BACKGROUND

Treatment of multilevel cervical spondylotic myelopathy/radiculopathy is a matter of debate, more so in elderly patients due to compromised physiology. We evaluated the clinical and radiological results of cervical fusion, using wedge-shaped tricortical autologous iliac graft and Orion plate for three-level anterior cervical discectomy in elderly patients.

MATERIALS AND METHODS

Twelve elderly patients with mean age of 69.7 years (65-76 years) were treated between April 2000 and March 2005, for three-level anterior cervical discectomy and fusion, using wedge-shaped tricortical autologous iliac graft and Orion plate. Outcome was recorded clinically according to Odom's criteria and radiologically in terms of correction of lordosis angle and intervertebral disc height span at the time of bony union. The mean follow-up was 29.8 months (12-58 months).

RESULTS

All the patients had a complete recovery of clinical symptoms after surgery. Postoperative score according to Odom's criteria was excellent in six patients and good in remaining six. Bony union was achieved in all the patients with average union time of 12 weeks (8-20 weeks). The mean of sum of three segment graft height collapse was 2.50 mm (SD = 2.47). The average angle of lordosis was corrected from 18.2 degrees (SD = 2.59 degrees ) preoperatively to 24.9 degrees (SD = 4.54 degrees ) at the final follow-up. This improvement in the radiological findings is statistically significant (P < 0.05).

CONCLUSION

Cervical fusion with wedge-shaped tricortical autologous iliac graft and Orion plate for three-level anterior cervical discectomy is an acceptable technique in elderly patients. It gives satisfactory results in terms of clinical outcome, predictable early solid bony union, and maintenance of disc space height along with restoration of cervical lordosis.

The safety of instrumented outpatient anterior cervical discectomy and fusion

BACKGROUND CONTEXT

Reported hospitalization times after an anterior cervical discectomy and fusion (ACDF) procedure range between 20 hours to 4 days. Reasons for this wide variation are manifold, but the safety of an instrumented ACDF in the setting of a hostile medical-legal climate is most likely the primary concern influencing such a discrepancy.

PURPOSE

The purpose of this study was to evaluate the safety and feasibility of performing single, two- and three-level ACDF with instrumentation on an outpatient or 23-hour observation period basis in order to potentially diminish the additional cost of hardware without compromising the purported benefits of surgery.

STUDY DESIGN/SETTING

A retrospective chart review of patients undergoing instrumented ACDF on an outpatient basis was performed.

PATIENT SAMPLE

A total of 103 patients with neck pain and/or radiculopathy undergoing ACDF were enrolled into this study.

OUTCOME MEASURES

Included the evaluation of intraoperative and perioperative complications, which were reported for a total of 6 months after surgery. Clinical examination and radiographical assessment, including plain radiographs and computed tomography and magnetic resonance imaging (when required), were performed to assess complications.

METHODS

Complications were divided into two groups: major and minor. Major complications included vertebral fracture and dehydration resulting in readmission. Minor complications included allergic reactions to medications that did not require hospitalization, and transient (< or = 3 months) neurologic deficit. A comprehensive literature search and meta-analysis was performed to generate a large comparison group in order to compare the complication rates in our outpatient series to those reported in the literature.

RESULTS

A total of 99 patients (96.1%) undergoing single and two-level ACDF were discharged less than 15 hours after their surgeries (median time: 8 hours; range: 2-15 hours), and 4 patients (3.9%) were discharged after a 23-hour observation period following three-level ACDF. The overall complication rate in our outpatient series was 3.8% (n=4), including 1.9% (n=2) major and 1.9% (n=2) minor complications. The overall complication rate in the 633 patient meta-analysis derived comparison group was 0.95% (n=6). The difference between overall complication rates was not found to be significantly different (p = .12). The hardware-related complication rate in the meta-analysis comparison group was 0.5% (n=3), and was not found to be significantly different from our rate of 0% (p < or = 1).

CONCLUSION

Performing ACDF with instrumentation on an outpatient basis is feasible, and it is not associated with higher overall or hardware-related complication rates as compared with complication rates reported in the literature, suggesting that this procedure is safe to perform on an outpatient basis.

Immediate Pain Improvement Is a Useful Predictor of Long-Term Favorable Outcome after Percutaneous Laser Disc Decompression for Cervical Disc Herniation

OBJECTIVE

The purpose of this study was to evaluate the long-term clinical outcome of percutaneous laser disc decompression (PLDD) for cervical disc herniation and to identify factors affecting long-term favorable outcome.

BACKGROUND DATA

PLDD using the Ho:YAG laser has been regarded as an effective alternative for soft disc herniation. However, little is known about long-term favorable outcome parameters.

METHODS

We retrospectively reviewed the clinical and radiological data of 60 patients who underwent PLDD with laser-assisted spinal endoscopy (LASE) for contained cervical soft disc herniation from January 1998 to January 2000. The clinical outcome was measured using the Macnab criteria. Statistical analysis was performed using Fisher's exact test. Sex, age, operated level and location of disc herniation, amount of laser energy, and time for symptom improvement were selected as parameters.

RESULTS

The mean follow-up period was 71.0 months (range, 59-83 months). The mean age was 45.7 years (range, 26-68 years), and the mean symptom duration was 13.0 months (range, 2-60 months). The Visual Analogue Scale (VAS) score was significantly improved from 7.9 preoperatively to 2.6 at the final follow-up (p < 0.001). At the final follow-up, 51 (85.0%) patients achieved a favorable outcome. Immediate (within 24 h) pain relief was achieved in 19 patients, and it was strongly related to long-term success (p = 0.006).

CONCLUSION

The long-term clinical outcome of PLDD with LASE was fairly good, with a success rate of 85%. Immediate pain relief is a useful prognostic factor predicting favorable outcome following the procedure.

Open-door laminoplasty for cervical myelopathy resulting from adjacent-segment disease in patients with previous anterior cervical decompression and fusion

STUDY DESIGN

This is a retrospective study of patients with cervical myelopathy resulting from adjacent-segment disease who were treated by open-door expansive laminoplasty.

OBJECTIVES

The purpose of this study was to evaluate the effectiveness of laminoplasty for cervical myelopathy resulting from adjacent-segment disease.

SUMMARY OF BACKGROUND DATA

Adjacent-segment disease is one of the problems associated with anterior cervical decompression and fusion. However, the optimal surgical management strategy is still controversial.

METHODS

Thirty-one patients who underwent open-door expansive laminoplasty for cervical myelopathy resulting from adjacent-segment disease and age- and sex-matched 31 patients with myelopathy who underwent laminoplasty as the initial surgery were enrolled in the study. The pre- and postoperative Japanese Orthopedic Association scores (JOA scores) and the recovery rate were compared between the two groups.

RESULTS

The average JOA scores in the patients with adjacent-segment disease and the controls were 9.2 +/- 2.6 and 9.4 +/- 2.3 before the expansive laminoplasty and 11.9 +/- 2.8 and 13.3 +/- 1.7 at the follow-up examination, respectively; the average recovery rates in the two groups were 37.1 +/- 22.4% and 50.0 +/- 21.3%, respectively (P = 0.04). The mean number of segments covered by the high-intensity lesions on the T2-weighted magnetic resonance images was 1.87 and 0.9, respectively (P = 0.001).

CONCLUSIONS

Moderate neurologic recovery was obtained after open-door laminoplasty in patients with cervical myelopathy resulting from adjacent-segment disc disease, although the results were not as satisfactory as those in the control group. This may be attributed to the irreversible damage of the spinal cord caused by persistent compression at the adjacent segments.

Treatment of anterior cervical pseudoarthrosis: posterior fusion versus anterior revision

BACKGROUND CONTEXT

Posterior fusion has been advocated as the most effective treatment of anterior cervical pseudoarthrosis. Authors cite the benefits of increased stability and avoiding the risk of dissection through anterior scar tissue. Despite these advantages, posterior fusion is a more extensive procedure from the standpoint of perioperative and postoperative recovery.

PURPOSE

The objective of this study is to compare the results of posterior fusions to revision anterior fusions for repair of anterior cervical pseudoarthrosis.

STUDY DESIGN/SETTING

This is a retrospective case series from a single institution.

PATIENT SAMPLE

120 patients with nonunion documented on flexion-extension radiographs, computed tomography (CT) scan or tomograms after an anterior cervical discectomy and fusion with at least 2-year follow-up.

OUTCOME MEASURES

Surgical data, status of fusion, complications, and any revision surgeries.

METHODS

Hospital and office records were reviewed to determine demographic data, surgical data, status of fusion, and any revision surgeries. Nonunion was confirmed during surgery.

RESULTS

Of the 120 patients included in the study, 27 had repeat anterior procedures and 93 had posterior procedures. The proportion of smokers, the number of surgical levels, and the average time to revision in each group were similar. The average operative time for the anterior revision surgery was 134.9 minutes (range 49 to 232 minutes) with an estimated blood loss of 102.7 cc. In the posterior revision surgery the average operative time was 138.9 minutes (range 35 to 356 minutes) and an average estimated blood loss of 282.1 cc. The patients in the anterior revision group had an average hospital stay of 2.3 days (1 to 5 days), whereas those in the posterior revision group had an average hospital stay of 4.4 days (3 to 8 days). There was a 4% complication rate in the anterior revision group and an 8% complication rate in the posterior revision group. Twelve of 27 patients (44%) in the anterior revision group, and 2 of 93 patients in the posterior revision group required a second revision surgery for persistent nonunion.

CONCLUSIONS

Based on these results, posterior fusion is more effective in treating anterior cervical pseudoarthrosis than revision anterior fusion. The higher fusion rate and lower incidence of repeat revision surgery offset the increased blood loss and longer recovery time associated with posterior cervical fusions.

Spinous process plate fixation as a salvage operation for failed anterior cervical fusion

✓The purpose of this retrospective review was to demonstrate the effectiveness of simple spinous process plate fixation as a salvage operation for failed anterior cervical fusion (ACF). In this technique, the spinous processes are securely sandwiched between a pair of plates with thorns, which are squeezed together by tightening screws that extend through the plates. The authors salvaged six failed ACFs (nonunion of bone graft, plate migration, or bone graft dislodgment) by conducting this fixation without bone grafting, or with an anterior or posterior local bone graft only. Anterior bone union was attained within 6 months in all cases. This technique is easy to perform and probably provides more mechanical strength than does conventional spinous process wiring, resulting in prompt fusion without the need for a new massive bone graft. This technique is a practical option in salvage operations for failed ACF.

Fusion rate of anterior cervical plating after corpectomy

PURPOSE

To evaluate the neurological recovery and fusion rate of patients with myelopathy who were treated with anterior corpectomy and anterior cervical plating.

METHODS

The results of 17 cervical myelopathy patients who underwent decompression and anterior cervical plating were retrospectively reviewed at a mean follow-up of 2 years.

RESULTS

By Kurokawa score, 82.4% of patients showed excellent-to-good results. The fusion rates of 2-level and 3-level anterior cervical corpectomy, and of anterior plate fixation were 100%. There were no implant- or graft-related complications. Transient dysphagia in 9 (52.9%) patients resolved after a mean of 3 months (range, 1-9 months).

CONCLUSION

The use of anterior cervical plating after anterior corpectomy and fusion with autologous bone graft greatly enhances arthrodesis. The improved fusion rate and low complication rate associated with anterior cervical plating may justify its use in the treatment of cervical spondylotic myelopathy.

An outcomes analysis of the treatment of cervical pseudarthrosis with posterior fusion

STUDY DESIGN

A retrospective review of 33 consecutive patients treated with posterior fusion and selective nerve root decompression for the treatment of pseudarthrosis following anterior cervical discectomy and fusion.

OBJECTIVES

Use standardized outcome measures to evaluate the results of posterior fusion with selective nerve root decompression as a treatment option for symptomatic pseudarthrosis of the cervical spine.

SUMMARY OF BACKGROUND DATA

Pseudarthrosis after anterior cervical discectomy and fusion has been recognized as a cause of continued cervical pain and unsatisfactory outcomes. Debate continues as to whether a revision anterior approach or a posterior fusion procedure is the best treatment for symptomatic cervical pseudarthrosis. To our knowledge, standardized outcome measures have not been used to evaluate the results of either surgical treatment option; therefore, it is difficult to evaluate outcomes in these patients, let alone compare surgical treatment options. Data on fusion rates in these two surgical treatment groups suggest a trend of a higher fusion rate with utilization of a posterior revision procedure, but the largest study to date includes the study of only 19 patients treated with a posterior fusion.

METHODS

Thirty-three consecutive patients with symptomatic pseudarthrosis following anterior cervical discectomy and fusion were treated with selective nerve root decompression and posterior fusion using iliac crest or local bone graft as well as posterior wiring and/or lateral mass plating. The average follow-up period was 46 months (range, 20-86 months). Patients were assessed using physical examination, flexion-extension lateral radiographs, and standardized outcome measures including the SF-36, Arthritis Impact Measurement Scales 2, and Cervical Spine Outcomes Questionnaire.

RESULTS

All 33 patients (100%) demonstrated a solid fusion at their most recent follow-up, and all 33 patients noted significant improvement in their preoperative symptoms. No difference in fusion status was noted between those treated with iliac crest versus patients treated with local bone graft--all had a solid fusion; 72% of the patients were satisfied with the result of their surgery. Cervical Spine Outcomes Questionnaire pain scales demonstrated 52% of patients reported mild or nopain at follow-up, whereas 20% described their pain as "discomforting" and 28% of the patients continued to report moderate to severe pain.

CONCLUSIONS

This is the first study to our knowledge to use standardized outcome measures to assess clinical outcome in patients treated with posterior fusion for pseudarthrosis after anterior cervical discectomy and fusion. Patients and surgeons need to understand the potential for success with this revision procedure but also be aware of the relatively high rate of continued moderate to severe pain observed in this patient population even after a solid fusion is achieved. All of the patients in this study fused with a single posterior fusion procedure, further supporting the relatively higher fusion rates observed in the literature using posterior fusion as a treatment for cervical pseudarthrosis. Our results also support the ability of surgeons to use local bone graft without iliac crest in a posterior fusion for cervical pseudarthrosis and therefore avoid the morbidity associated with iliac crest bone graft harvest.

Cost-effectiveness of single-level anterior cervical discectomy and fusion for cervical spondylosis

STUDY DESIGN

Cost-effectiveness analysis with retrospective cost analysis and literature review.

OBJECTIVE

To determine the relative cost-effectiveness of anterior cervical discectomy and fusion (ACDF) with autograft, allograft, and allograft with plating for single-level anterior cervical spondylosis.

SUMMARY OF BACKGROUND DATA

There are several accepted methods of surgically treating single-level cervical spondylosis anteriorly. No study has clearly demonstrated the superiority of one method over the alternatives. The techniques may differ in their operative risks and resource use, perioperative complications, short-term outcome, and long-term outcome and complications. Formal cost-effectiveness analysis (CEA) provides a structure for analyzing many variables and comparing different treatment outcomes. Sensitivity analysis is used to test the robustness of the model and to determine variables that have significant effects on the results. Future areas of research and refinements of the CEA model can be developed from these findings.

METHODS

A retrospective review of hospital charges was performed for 78 patients who underwent single-level ACDF with allograft alone or ACDF with allograft and plating (ACDFP). The charges were converted to estimated costs for fiscal year 2000 using the ratio of costs to charges method. A CEA model was developed consisting of a decision-analysis model for the first year postsurgery and a Markov model for the next 4 years after surgery. Probabilities and outcome utilities were estimated from the literature. Outcome was measured in quality-adjusted life years (QALYs), and incremental CEA was performed. Several variables were tested in one-way sensitivity analysis.

RESULTS

Compared with ACDF with autograft, ACDF with allograft offered an improvement in quality of life at a cost of 496 dollars per QALY. ACDFP provided additional gains in quality of life compared with ACDF with allograft at a cost of 32,560 dollars per QALY in the base case analysis. In sensitivity analysis, these estimates varied between 417 dollars and 741 dollars per QALY and between 19,090 dollars per QALY and domination of ACDFP by ACDF with allograft, respectively. The results were most sensitive to assumptions regarding differences in the length of the postoperative recovery period.

CONCLUSIONS

ACDF with allograft offers a benefit relative to ACDF with autograft at a cost of 496 dollars per QALY. ACDFP has a benefit relative to ACDF with allograft at an approximate cost of 32,560 dollars per QALY. CEA provides a method for comparing the benefits and risks of these three procedures. Further research needs to be performed regarding these procedures, particularly examining the postoperative recovery period.

Anterior corpectomy and fusion with fibular strut grafts for multilevel cervical myelopathy

OBJECT

The authors conducted a study to investigate the long-term results and postoperative complications of a new surgical technique, fibular strut graft-assisted anterior corpectomy and fusion for multilevel (> four) cervical myelopathy. Multilevel anterior corpectomy and subsequent strut graft placement is considered a challenging procedure because of complications relating to graft dislodgment, pseudarthrosis, greater operative duration, and increased blood loss.

METHODS

The study comprised 100 patients with cervical myelopathy who underwent anterior corpectomy and fusion and fibular strut graft placement at more than four disc space levels between 1989 and 1998. Single-screw fixation was used in conjunction with the autologous strut graft. Preoperative and postoperative plain radiographs, computerized tomography myelograms, and magnetic resonance images were obtained for assessment of fusion status. All complications and outcomes were analyzed based on clinical records to evaluate the results of the technique. There were no cases of graft dislodgment. The graft union rate was 85%. Analysis of clinical data showed that pseudarthrosis had no adverse effect on the clinical results. Adjacent-level disc degeneration occurred in 12% of patients, but in all cases the patients were asymptomatic. In 9% of cases C-5 palsy was observed but it recovered spontaneously. There were no infections and no case of neurological deterioration.

CONCLUSIONS

With this new graft technique, graft dislodgment, the major complication associated with strut graft surgery, was resolved completely. This simple technique involving single-screw fixation provided good results when used in conjunction with anterior decompression and strut graft fixation with a very low incidence of complications.

Cage containing a biphasic calcium phosphate ceramic (Triosite) for the treatment of cervical spondylosis

BACKGROUND

We evaluated the fusion efficacy and clinical outcomes of a cage containing a biphasic calcium phosphate ceramic (Triosite) in treating cervical spondylosis.

METHODS

We randomly divided 100 patients with cervical spondylosis undergoing anterior discectomy with interbody polyetheretherketone (PEEK) fusion into 2 groups in the past 2 years: group A (n = 50), PEEK cage containing a biphasic calcium phosphate ceramic (Triosite), and group B (n = 50), PEEK cage containing an autogenous iliac bone graft. We compared the fusion rate, fusion time, spinal curvature, and neuroforamen size between the 2 groups. We also compared excess operation time, excess blood loss, hospital stay, complications, and neurological recovery status between the groups.

RESULTS

The fusion rates were 57%, 67%, 77%, 82%, 92%, and 100% in group A and 81%, 86%, 95%, 95% 100%, and 100% in group B in the first 6 postoperative months. The fusion rate in group A was significantly lower than that in group B in the first 5 months after the procedure (P < .05 and P < .01, respectively), but the fusion rate reached 100% in both groups by the sixth month. Within the first 6 months, as the fusion level increased, the fusion rates reduced and time to fusion was delayed in both groups. There were no donor site complications in group A. However, 3 patients (6%) from group B experienced complications (1, wound infection; 1, numbness of thigh; and 1, subcutaneous hematoma) (P < .001). The hospital stay was shorter in group A (4.43 +/- 2.36 days) than in group B (7.00 +/- 3.77 days) (P = .001). The mean excessive blood loss and excessive operative time for an iliac bone graft in group B were 15 +/- 5 mL and 10 +/- 6 minutes. There was no statistical significance in spinal curve correction, neuroforamen enlargement, and neurological recovery.

CONCLUSIONS

A cage containing a biphasic calcium phosphate ceramic resulted in complete fusion by the sixth postoperative month, although the fusion rate was lower than that in a cage containing an autograft during the first 5 months after the operation and the time to fusion was delayed. Using a cage containing a biphasic calcium phosphate ceramic leads to a shorter hospital stay, less blood loss, shorter operative time, and no donor site complications. It seemed to be a good substitute for cervical spondylotic fusion.