Evidence-based analysis of adjacent segment degeneration and disease after ACDF: a systematic review

Background context

Follow-up studies of patients undergoing anterior cervical discectomy and interbody fusion (ACDF) have demonstrated varying degrees of radiographic degeneration at adjacent levels, with most cases being asymptomatic (adjacent segment degeneration, ASDeg) and far fewer being symptomatic (adjacent segment disease, ASDz). Controversy remains as to whether these conditions are related to altered biomechanics or represent the natural history of cervical spondylosis at the adjacent segment.

Purpose

To provide an evidence-based analysis of the peer-reviewed literature on clinical studies of ASDeg and ASDz after ACDF.

Study design/setting

Systematic review of existing literature.

Methods

The MEDLINE database was queried for clinical studies reporting ASDeg and/or ASDz after ACDF. Articles written in the English language with a minimum follow-up of 2 years were independently reviewed and analyzed by two authors, and the level of evidence was assigned. Data were pooled to generate summary outcomes and organized by number of levels, technique, and graft/implants.

Results

Of the 238 articles returned from the MEDLINE database query, 14 met inclusion criteria. An average of 168 patients was enrolled per study with an average follow-up of 106.5 months. Graft materials, cage design, plate fixation system, and length of fusion varied widely. Additionally, no clear standard was seen for radiographic assessment modalities (eg, plain lateral radiograph, flexion-extension radiographs, computed tomography, or magnetic resonance imaging). Validated clinical outcome measures were used in 43% (6/14) of the studies. The average incidence of ASDeg was 47.33% (459.14/970) with a range from 16% to 96%. The frequency-weighted average for ASDz was 11.99% (263.70/2,199) with a range from 1.80% to 36.00%. Follow-up ranged from 24 to 296 months with no reliable commonalities, which prohibited a meta-analysis.

Conclusions

This review highlights the heterogeneous methodology of the peer-reviewed literature on ASDeg and ASDz after ACDF and the paucity of high-level clinical data published on these conditions. Despite the low level of evidence to define the incidence of ASDeg and ASDz, it is clear that radiographic ASDeg is more common than symptomatic ASDz, indicating that adjacent segment pathology remains subclinical in a large subset of patients. This analysis underscores the need for standardized radiographic measures in the assessment of ASDeg and validated clinical outcome measures for ASDz after ACDF. Consistent methodology and multi-surgeon collaboration may improve the quality of clinical data on ASDeg and ASDz and elucidate the true etiology and incidence of these conditions.     

Anterior cervical discectomy and fusion versus anterior cervical corpectomy and fusion for multilevel cervical spondylosis: a systematic review

Introduction  

There is considerable controversy as to which technique is best option for reconstruction after multilevel anterior decompression for cervical spondylosis. The aim of this study was to compare the clinical and radiographic results and complications of anterior cervical discectomy fusion (ACDF) and anterior cervical corpectomy fusion (ACCF) in the treatment of multi-level cervical spondylosis.     

Three- and four-level anterior cervical discectomy and fusion with a PEEK cage and plate construct

Introduction

Three- or four-level anterior cervical discectomy and fusion with autograft and plate fixation have demonstrated relatively good fusion rates and outcomes, but donor site morbidity and the limitations of autograft harvest remain problematic. The purpose of this study is to assess the radiographic and clinical outcomes of three- or four-level anterior cervical discectomy and fusion with a PEEK cage and plate construct.

Methods

This retrospective review included 43 consecutive patients who underwent three- or four-level anterior cervical discectomy and fusion with a PEEK cage and plate construct (three level: 39 cases, four level: 4 cases). The fusion rate, time to fusion, Cobb angle and disc height were assessed radiographically. Clinical outcomes were evaluated with the VAS, NDI, and SF36 scores. Complications were also recorded.

Results

Solid fusion was achieved in all the patients, and mean time to fusion was 13.7 ± 5.1 weeks. The postoperative Cobb angle, lordotic angle, and disc height (5.6°, 10.5° and 3.15 mm, respectively) increased significantly compared to preoperative values (p = 0.038, p = 0.032, and p = 0.0004, respectively), and these improvements were maintained through final follow-up. The postoperative NDI (17.2), VAS (2.8), and SF36 (13.1) scores increased significantly compared to the preoperative scores (p = 0.026, p = 0.0007 and p = 0.041, respectively). Complications included three cases of respiratory difficulty, four cases of dysphagia and one case of hoarseness. There were no cases of donor site morbidity.

Conclusions

Three- or four-level anterior cervical discectomy and fusion with a PEEK cage, and plate construct provide good clinical and radiographic outcomes including high fusion rates, low complication rates, low donor site morbidity, and good maintenance of the lordotic angle and disc height in the treatment of multilevel cervical spondylosis.     

Complications,outcomes, and need for fusion after minimally invasive posterior cervical foraminotomy and microdiscectomy

Background context

Posterior cervical foraminotomy (PCF) with or without microdiscectomy (posterior cervical discectomy [PCD]) is a frequently used surgical technique for cervical radiculopathy secondary to foraminal stenosis or a laterally located herniated disc. Currently, these procedures are being performed with increasing frequency using advanced minimally invasive techniques. Although the safety and efficacy of minimally invasive PCF/PCD (MI-PCF/PCD) have been established, reports on long-term outcome and need for secondary surgical intervention at the index or adjacent level are lacking.

Purpose

To determine the rates of complications, long-term outcomes, and need for secondary surgical intervention at the index or adjacent level after MI-PCF and microdiscectomy.

Study design

Retrospective analysis of a prospective cohort.

Patient sample

Seventy patients treated with MI-PCF and/or MI-PCD for cervical radiculopathy.

Outcome measures

Visual Analog Scale for neck/arm (VAS_N/A) pain and Neck Disability Index (NDI).

Methods

Ninety-seven patients underwent MI-PCF with or without MI-PCD between 2002 and 2011. Adequate prospective follow-up was available for 70 patients (95 cervical levels). The primary outcome assessed was need for secondary surgical intervention at the index or adjacent level. The secondary outcomes assessed included complications and improvements in NDI and VAS_N/A scores. All complications were reviewed. Mixed-model analyses of variance with random subject effects and autoregressive first-order correlation structures were used to test for differences among NDI, VAS_A, and VAS_N measurements made over time while accounting for the correlation among repeated observations within a patient. All statistical hypothesis tests were conducted at the 5% level of significance.

Results

Patients were followed for a mean of 32.1 months. Of 70 patients operated, there were 3 (4.3%) complications (1 cerebrospinal fluid leak, 1 postoperative wound hematoma, and 1 radiculitis), none of which required a secondary operative intervention. Five patients required an anterior cervical discectomy and fusion (eight total levels fused) on average 44.4 months after the index surgery. Of those, five (5.3%) were at the index level and three (2.1%) were at adjacent levels. Neck Disability Index scores improved significantly (p<.0001) immediately postoperatively and continued to decrease gradually with time. Visual Analog Scale for neck/arm scores improved significantly (p<.0001) from baseline immediately postoperatively but tended to plateau with time.

Conclusions

Minimally invasive PCF with or without MI-PCD is an excellent alternative for cervical radiculopathy secondary to foraminal stenosis or a laterally located herniated disc. There is a low rate (1.1% per index level per year) of future index site fusion and a very low rate (0.9% per adjacent level per year) of adjacent-level disease requiring surgery.     

Efficacy of Postoperative Radiograph for Evaluating the Prevertebral Soft Tissue Swelling after Anterior Cervical Discectomy and Fusion

Background

After surgery for degenerative spinal disease by the anterior approach, the degree of soft tissue swelling can be assessed simply using plain radiographs. However, there are little studies according to the surgical methods or extent of surgery, and no study had addressed the clinical meaning of swelling determined by plain radiography. The purpose of this study was to evaluate the clinical significance of prevertebral soft tissue swelling (PSTS) after anterior cervical fusion with plate fixation for the treatment of degenerative cervical spinal disorders.

Methods

One hundred and thirty-five patients that underwent anterior cervical fusion with plate augmentation for degenerative cervical spondylosis were included in this study. PSTS differences were analyzed with respect to numbers of fusion segments and location of fusion. Cases were divided into two groups based on the amount of PSTS, and incidences of dyspnea, dysphagia, dysphonia were evaluated.

Results

PSTS increments were significantly greater in patients that had undergone multi-level or high-level fusion. Complications of dyspnea, dysphagia and dysphonia were found more frequently in patients with marked PSTS group.

Conclusions

Increments of PSTS after anterior cervical fusion for degenerative spinal disorders are greater and incidences of complications are higher in patients that undergo multi-level or high-level fusion. Thus, measurement of PSTS using consecutive cervical lateral radiographs after anterior cervical surgery is clinically meaningful procedure.     

Progressive severe kyphosis as a complication of multilevel cervical percutaneous facet neurotomy: a case report

Background context

Percutaneous facet neurotomy is a procedure commonly used for the treatment of pain thought to originate from zygoapophyseal joint dysfunction. Some practitioners have also used this technique to treat cervicogenic headache. Previously reported complications for this procedure have been minimal and have included dysthesias and local pain.

Study design

Case report.

Methods

Bilateral multilevel cervical percutaneous facet neurotomies were used to treat a patient suffering from a chronic headache and neck pain that had failed to respond to extensive medical management.

Results

Within days of completing the bilateral facet neurotomies, the patient developed head drop. Subsequent electromyography revealed denervation of the patient's paraspinous muscles. Initially the patient was managed conservatively in a cervical collar with the hope that he would recover some function. After few years, the patient developed fixed kyphotic deformity. Correction of the patient's deformity required multilevel anterior cervical discectomy and fusion followed by posterior instrumented fusion.

Conclusions

When performing multilevel percutaneous cervical facet neurotomies, there is a risk of paraspinous muscle denervation, and subsequent kyphotic deformity may occur. The likelihood of this rare and previously unreported complication can probably be reduced by proper needle positioning and by minimizing the number of levels at which the procedure is performed.     

There is no increased risk of adjacent segment disease at the cervicothoracic junction following an anterior cervical discectomy and fusion to C7

Background Context

Anterior cervical discectomy and fusion (ACDF) is a very common operative intervention for the treatment of cervical spine degenerative disease in those who have failed non-operative measures. However, studies examining long-term follow-up on patients who underwent ACDF reveal evidence of radiographic and clinical degenerative disc disease at the levels adjacent to the fusion construct. Consistent with other junctional regions of the spine, the cervicothoracic junction (CTJ) has significant morphologic variations. As a result, the CTJ undergoes significant static and dynamic stress. Given these findings, there has been some thought that ACDF down to C7 may experience additional risks for adjacent segment degeneration/disease (ASD) when compared with ASDFs that are cephalad to C7.

Anterior cervical plating enhances arthrodesis after discectomy and fusion with cortical allograft

OBJECTIVE: Anterior plate fixation has gained widespread acceptance for the treatment of cervical spondylosis, theoretically enhancing the rate of arthrodesis. There are few studies comparing fusion rates after anterior cervical discectomy and fusion (ACDF) with and without a plate. The purpose of this study was to evaluate the efficacy of anterior cervical plating for fusion enhancement after one- and two-level ACDF with cortical allograft. METHODS: A retrospective review was performed with 251 patients who underwent one- or two-level ACDF with cortical allograft and plate stabilization between 1993 and 1999. An independent surgeon reviewer determined fusion status and complications. A successful fusion was defined by the absence of lucency around the graft, evidence of bridging bone between the endplate and the graft, and the absence of movement on dynamic imaging scans. Follow-up data, ranging from 9 months to 3.6 years, were available for 233 patients. A control group of 289 patients who underwent ACDF without plating was described in a previously published report by the senior author (RWH). Therefore, a total of 540 patients were evaluated for determination of the efficacy of anterior cervical plating with cortical allograft bone. Statistical significance was determined by chi(2) test. RESULTS: The fusion rates for one- and two-level ACDF with anterior fixation were 96 and 91%, respectively, compared with 90 and 72% for one- and two-level ACDF without anterior fixation. The observed increases in fusion rates for both one- and two-level procedures proved to be statistically significant (P < 0.05). There were no recorded infectious, neurological, or graft-related complications among the cohort treated with anterior cervical plating. Compared with the results for the cohort treated without anterior cervical plates, there was a statistically significant decrease in the graft-related complication rate with the application of plates (P < 0.001). Two patients who received plates were noted to have adjacent-segment degenerative changes that required surgical intervention. No hardware fractures were noted; however, one patient was noted to have a single displaced screw, without clinical consequences. CONCLUSION: The use of anterior cervical plating after one- and two-level ACDF with allograft cortical bone significantly enhanced arthrodesis. The improved fusion rate and negligible complication rate associated with anterior cervical plating are compelling factors justifying its use in the treatment of cervical spondylosis.     

Thirty-day readmissions after elective spine surgery for degenerative conditions among US Medicare beneficiaries

Background context

Readmissions within 30 days of hospital discharge are undesirable and costly. Little is known about reasons for and predictors of readmissions after elective spine surgery to help plan preventative strategies.

Purpose

To examine readmissions within 30 days of hospital discharge, reasons for readmission, and predictors of readmission among patients undergoing elective cervical and lumbar spine surgery for degenerative conditions.

Study design

Retrospective cohort study.

Patient sample

Patient sample includes 343,068 Medicare beneficiaries who underwent cervical and lumbar spine surgery for degenerative conditions from 2003 to 2007.

Outcome measures

Readmissions within 30 days of discharge, excluding readmissions for rehabilitation.

Methods

Patients were identified in Medicare claims data using validated algorithms. Reasons for readmission were classified into clinically meaningful categories using a standardized coding system (Clinical Classification Software).

Results

Thirty-day readmissions were 7.9% after cervical surgery and 7.3% after lumbar surgery. There was no dominant reason for readmissions. The most common reasons for readmissions were complications of surgery (26%–33%) and musculoskeletal conditions in the same area of the operation (15%). Significant predictors of readmission for both operations included older age, greater comorbidity, dual eligibility for Medicare/Medicaid, and greater number of fused levels. For cervical spine readmissions, additional risk factors were male sex, a diagnosis of myelopathy, and a posterior or combined anterior/posterior surgical approach; for lumbar spine readmissions, additional risk factors were black race, Middle Atlantic geographic region, fusion surgery, and an anterior surgical approach. Our model explained more than 60% of the variability in readmissions.

Conclusions

Among Medicare beneficiaries, 30-day readmissions after elective spine surgery for degenerative conditions represent a target for improvement. Both patient factors and operative techniques are associated with readmissions. Interventions to minimize readmissions should be specific to surgical site and focus on high-risk subgroups where clinical trials of interventions may be of greatest benefit.     

Outcome of single level anterior cervical discectomy and fusion using nano-hydroxyapatite/polyamide-66 cage

Background:

Cages have been widely used for the anterior reconstruction and fusion of cervical spine. Nonmetal cages have become popular due to prominent stress shielding and high rate of subsidence of metallic cages. This study aims to assess fusion with n-HA/PA66 cage following one level anterior cervical discectomy.

Materials and Methods:

Forty seven consecutive patients with radiculopathy or myelopathy underwent single level ACDF using n-HA/PA66 cage. We measured the segmental lordosis and intervertebral disc height on preoperative radiographs and then calculated the loss of segmental lordosis correction and cage subsidence over followup. Fusion status was evaluated on CT scans. Odom criteria, Japanese Orthopedic Association (JOA) and Visual Analog Pain Scales (VAS) scores were used to assess the clinical results. Statistically quantitative data were analyzed while Categorical data by χ² test.

Results:

Mean correction of segmental lordosis from surgery was 6.9 ± 3.0° with a mean loss of correction of 1.7 ± 1.9°. Mean cage subsidence was 1.2 ± 0.6 mm and the rate of cage subsidence (>2 mm) was 2%. The rate of fusion success was 100%. No significant difference was found on clinical or radiographic outcomes between the patients (n=27) who were fused by n-HA/PA66 cage with pure local bone and the ones (n=20) with hybrid bone (local bone associating with bone from iliac crest).

Conclusions:

The n-HA/PA66 cage is a satisfactory reconstructing implant after anterior cervical discectomy, which can effectively promote bone graft fusion and prevent cage subsidence.     

Additional anterior plating enhances fusion in anteroposteriorly stabilized thoracolumbar fractures

Introduction

To prospectively evaluate the potential radiological and clinical effect of the additional application of an anterior plate in anteroposteriorly stabilized thoracolumbar fractures.

Patients and methods

75 consecutive patients with unstable thoracolumbar fractures underwent posterior (internal fixator) and anterior stabilization (corpectomy cage with local autologous bone grafting). 40 (53.3%) patients received an additional anterior plate (Group A), while 35 (46.6%) (Group B) did not. Plain X-rays and CT-scans were obtained pre- and postoperatively, after 12 months and at the last follow-up (mean 32 months, range 22–72). Loss of reduction, cage subsidence to adjacent vertebrae, fusion rates and clinical results were evaluated.

Results

66 (87%) patients (36 Group A; 30 Group B) were available for follow-up. Patients in both groups were comparable regarding age, gender, comorbidities, localization and classification of fracture. Average loss of reduction was 2.4° in Group A, and 3.1° in Group B (not significant). Cage subsidence did not differ significantly between both groups, too. However, after 12 months the rate of continuous osseous bridging between endplates was significantly higher in Group A (63% vs. 25%) (p < 0.05). After 32 months this difference was even higher (81% vs. 33%) (p < 0.001). The bony fusion mass was located beneath or around the anterior plate in 94% of patients. There was no significant difference in clinical outcome.

Conclusions

Additional anterior plating in anteroposteriorly stabilized thoracolumbar fractures leads to significant faster fusion but does neither influence reduction loss nor cage subsidence. The anterior plate serves as a pathway for bone growth and increases biomechanical stability, resulting in a higher fusion rate.     

Intramedullary arachnoid cyst in association with cervical spondylosis: case report

Background context

Intramedullary spinal arachnoid cysts are considered to be very rare, and only 11 cases have been reported previously. Development of such a cyst in association with marked cervical spondylosis has not been reported until recently.

Purpose

Brief review of reported cases and debate on likely treatment strategy when such a cyst is associated with symptomatic spondylosis.

Study design

To report the first example of a cervicothoracic intramedullary arachnoid cyst along with a symptomatic cervical spondylosis.

Methods

Evaluation of quadriparesis in a 58-year-old female resulted in detection of a cervical spondylotic stenosis that was accompanied with an intramedullary cystic lesion. Parallel management of both pathologies was through a wide laminectomy extending from the lower edge of C3 to T2 with subsequent fenestration and partial resection of the cyst wall via an appropriate dorsal entry root zone myelotomy. Cervicothoracic instrumentation from C3 down to T2 was done to prevent postlaminectomy deformity.

Result

Histopathological findings were consistent with the diagnosis of arachnoid cyst. Postoperatively, the patient exhibited marked improvement in neurologic status.

Conclusion

Through the review of the current case, first example from the literature, we concluded that surgery should target toward the proper management of both pathologies in a single-stage operation.     

Differences in the surgical treatment of recurrent lumbar disc herniation among spine surgeons in the United States

Background context

There are often multiple surgical treatment options for a spinal pathology. In addition, there is a lack of data that define differences in surgical treatment among surgeons in the United States.

Purpose

To assess the surgical treatment patterns among neurologic and orthopedic spine surgeons in the United States for the treatment of one- and two-time recurrent lumbar disc herniation.

Study design

Electronic survey.

Patient sample

An electronic survey was delivered to 2,560 orthopedic and neurologic surgeons in the United States.

Outcome measures

The response data were analyzed to assess the differences among respondents over various demographic variables. The probability of disagreement is reported for various surgeon subgroups.

Methods

A survey of clinical and radiographic case scenarios that included a one- and two-time lumbar disc herniation was electronically delivered to 2,560 orthopedic and neurologic surgeons in the United States. The surgical treatment options were revision microdiscectomy, revision microdiscectomy with in situ fusion, revision microdiscectomy with posterolateral fusion using pedicle screws, revision microdiscectomy with posterior lumbar interbody fusion/transforaminal lumbar interbody fusion (PLIF/TLIF), anterior lumbar interbody fusion (ALIF) with percutaneous screws, ALIF with open posterior instrumentation, or none of these. Significance of p=.01 was used to account for multiple comparisons.

Results

Four hundred forty-five surgeons (18%) completed the survey. Surgeons in practice for 15+ years were more likely to select revision microdiscectomy compared with surgeons with fewer years in practice who were more likely to select revision microdiscectomy with PLIF/TLIF (p<.001). Similarly, those surgeons performing 200+ surgeries per year were more likely to select revision microdiscectomy with PLIF/TLIF than those performing fewer surgeries (p=.003). No significant differences were identified for region, specialty, fellowship training, or practice type. Overall, there was a 69% and 22% probability that two randomly selected spine surgeons would disagree on the surgical treatment of two- and one-time recurrent disc herniations, respectively. This probability of disagreement was consistent over multiple variables including geographic, practice type, fellowship training, and annual case volume.

Conclusions

Significant differences exist among US spine surgeons in the surgical treatment of recurrent lumbar disc herniations. It will become increasingly important to understand the underlying reasons for these differences and to define the most cost-effective surgical strategies for these common lumbar pathologies as the United States moves closer to a value-based health-care system.     

Failure of resorbable plates and screws in an ovine model of anterior cervical discectomy and fusion

Background context

Containment plates are often placed anteriorly in anterior cervical discectomy and fusion (ACDF) to provide stability and prevent migration of the interbody device or autograft. The main advantage of a bioresorbable plate over the typical metallic plate is that it will resorb after fusion has occurred, thus mitigating any long-term instrumentation-related complications. Furthermore, the plates are radiolucent, allowing complete visualization of the fusion site and eliminating imaging artifact.

Purpose

To evaluate radiographic fusion, mechanical success rates, and histologic characteristics of a bioresorbable containment plate and screws in a 3-month ovine model of ACDF.

Study design

An in vivo prospective analysis of resorbable anterior cervical plates and screws for use in ACDF in an ovine model.

Methods

Six sheep underwent C2–C3 and C4–C5 discectomies. Fusions were performed using a polyetheretherketone cage filled with autograft bone. A polymeric plate (70/30 poly-dl-lactic acid), and four screws were placed over an intervertebral disc spacer at each of these two levels. After 3 months, the animals were euthanized and radiographically imaged. Radiographs were analyzed for fusion and instrumentation failures. Functional spinal units were harvested for histologic processing and evaluation.

Results

Radiographic fusion was noted in three of the 12 levels with no evidence of device failure at any of the levels. However, at necropsy, it was observed that six of the 12 specimens had either a broken screw or a cracked plate. These gross observations were confirmed within the histologic sections. Fusion was verified histologically at C2–C3 in three of the six sheep; none of the fusions were successful at C4–C5. Histologic analysis also found that the tissue surrounding the plate and disc spacer consisted of vascularized fibrous tissue with islands of active woven bone. Inflammatory cells were rarely observed.

Conclusions

Although the bioresorbable plates and screws did not elicit an iatrogenic tissue response, a high percentage of them failed mechanically. This phenomenon was difficult to observe radiographically, as the radiolucent markers were not able to convey these instrumentation failures. Additionally, there was only a 25% fusion rate. These findings suggest that resorbable implant materials with the current biomechanical and chemical properties are inadequate for cervical fusion. The results of this study strongly suggest that radiographic outcomes alone may not be adequate and that gross or histologic methods should accompany radiographs in studies of bioresorbable materials in animal models.     

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° (SD = 2.59°) preoperatively to 24.9° (SD = 4.54°) 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.     

Retrograde ejaculation after anterior lumbar interbody fusion with and without bone morphogenetic protein-2 augmentation: a 10-year cohort controlled study

Background context

Retrograde ejaculation (RE) is a complication of anterior lumbar interbody fusion (ALIF) techniques. Most commonly, this results from mechanical or inflammatory injury to the superior hypogastric plexus near the aortic bifurcation. Bone morphogenetic protein-2 (BMP-2) has been used in spinal fusions and has been associated with inflammatory and neuroinflammatory adverse reactions, which may contribute to RE development after anterior lumbar surgery.

Purpose

While controlling for anterior approach technique, we compared the incidence of RE with and without rhBMP-2 exposure, in large, matched cohorts of patients after ALIF.

Study design

Retrospective analysis of 10 years of prospectively gathered outcomes data on consecutive-patient cohorts having the same anterior exposure technique for ALIF with and without rhBMP-2 use.

Patient sample

All male patients without baseline sexual incapacity and having ALIF for lumbar spondylosis or spondylolisthesis of the lowest one or two lumbar levels with and without rhBMP-2, from 2002 through 2011.

Outcome measures

Diagnosis of RE as a new finding after ALIF compared against BMP-2 exposure, comorbid conditions, and other urological complications after ALIF surgery.

Methods

From the comprehensive surgical database at a high volume, university practice, male subjects having ALIF at one (L5/S1) or two levels (L4/5, L5/S1) from 2002 to 2011 were identified. Baseline comorbid factors, postoperative urinary catheter/retention events, and RE events were recorded and comparative incidence compared.

Results

There were four consecutive-patient cohorts identified: one before rhBMP-2 use was adopted (n=174), two cohorts in which BMP-2 use was routine (n=88 and n=151), and one final cohort after BMP-2 use was discontinued from routine use (n=59). The cohorts with and without BMP-2 exposure were closely comparable for age, approach, levels of surgery, comorbid factors affecting RE. Of 239 patients with ALIF and exposure to BMP-2, RE was diagnosed in 15 subjects (6.3%), compared with an RE diagnosis rate of two of 233 control patients without BMP-2 exposure (0.9%; p=.0012). Urinary retention after bladder catheter removal was also more frequently observed in patients exposed to BMP-2 (9.7%) compared with control patients (4.6%; p=.043). Of the baseline comorbid factors, medical or surgical treatment for prostatic hypertrophy disease was associated with an increased risk of RE in the BMP-2 patients (p=.034).

Conclusions

This study confirms previous reports of a higher rate of RE in ALIF procedures using rhBMP-2 and an open anterior approach to the spine. This effect may be associated with an increased risk of postoperative urinary retention after BMP-2 exposure. The magnitude of the RE effect may be increased with concomitant prostatic disease treatments.     

Subsidence and Nonunion after Anterior Cervical Interbody Fusion Using a Stand-Alone Polyetheretherketone (PEEK) Cage

Background

The purposes of the present study are to evaluate the subsidence and nonunion that occurred after anterior cervical discectomy and fusion using a stand-alone intervertebral cage and to analyze the risk factors for the complications.

Methods

Thirty-eight patients (47 segments) who underwent anterior cervical fusion using a stand-alone polyetheretherketone (PEEK) cage and an autologous cancellous iliac bone graft from June 2003 to August 2008 were enrolled in this study. The anterior and posterior segmental heights and the distance from the anterior edge of the upper vertebra to the anterior margin of the cage were measured on the plain radiographs. Subsidence was defined as ≥ a 2 mm (minor) or 3 mm (major) decrease of the segmental height at the final follow-up compared to that measured at the immediate postoperative period. Nonunion was evaluated according to the instability being ≥ 2 mm in the interspinous distance on the flexion-extension lateral radiographs.

Results

The anterior and posterior segmental heights decreased from the immediate postoperative period to the final follow-up at 1.33 ± 1.46 mm and 0.81 ± 1.27 mm, respectively. Subsidence ≥ 2 mm and 3 mm were observed in 12 segments (25.5%) and 7 segments (14.9%), respectively. Among the expected risk factors for subsidence, a smaller anteroposterior (AP) diameter (14 mm vs. 12 mm) of cages (p = 0.034; odds ratio [OR], 0.017) and larger intraoperative distraction (p = 0.041; OR, 3.988) had a significantly higher risk of subsidence. Intervertebral nonunion was observed in 7 segments (7/47, 14.9%). Compared with the union group, the nonunion group had a significantly higher ratio of two-level fusion to one-level fusions (p = 0.001).

Conclusions

Anterior cervical fusion using a stand-alone cage with a large AP diameter while preventing anterior intraoperative over-distraction will be helpful to prevent the subsidence of cages. Two-level cervical fusion might require more careful attention for avoiding nonunion.     

The use of freeze-dried fibular allograft in anterior cervical fusion.

Eighty-three segmental fusions were performed on 42 patients who underwent anterior cervical discectomy and fusion with freeze-dried fibular allograft for cervical spondylosis. Fusions were carried out over one to four levels. The mean follow-up period was 22.1 months (range, 9-47 months). The patients had both clinical and radiographic follow-up. Eighty-eight percent of the patients were found to have excellent or good clinical results. Radiographic follow-up revealed that 92% of the grafts obtained complete or partial union by 6 months after surgery. Forty patients were shown to be radiographically stable on lateral flexion and extension films by 8 weeks after surgery. The use of freeze-dried fibular allograft is a safe and efficacious procedure.     

前路选择性间隙减压融合术治疗老年多节段颈椎病

目的评价前路选择性间隙减压融合术治疗65岁以上老年多节段颈椎病的临床疗效。方法回顾性分析有完整随访资料的35例手术患者,根据症状、体征及影像学结果行选择性间隙减压植骨融合内固定术。采用日本骨科学会（Japanese Orthopaedic Association,JOA）评分和Odom标准进行临床疗效评定。结果手术时间为（86．5±27．1）min,术中出血量为（95．7±42．9）mL。术前JOA评分为（8．4±2．6）分,末次随访时为（13．1±1．7）分,改莳率平均为58．7％,Odom优良率为82．4％。末次随访时均获骨性融合,内固定位置良好。结论术前充分准备,准确评估．正确选择减压节段,前路选择性间隙减压融合术是治疗老年多节段颈椎病的一种安全有效的手术方式：     

Posterior lumbar interbody fusion for aged patients with degenerative spondylolisthesis: is intentional surgical reduction essential?

Background context

Surgical reduction and posterior lumbar interbody fusion (PLIF) is commonly used to recover segmental imbalance in degenerative spondylolisthesis. However, whether intentional reduction of the slipped vertebra during PLIF is essential in aged patients with degenerative spondylolisthesis remains controversial.

Purpose

We compared the outcomes of surgical reduction and fusion in situ among aged patients who underwent PLIF for degenerative spondylolisthesis.

Study design

A prospective randomized clinical trial on the surgical treatment of degenerative spondylolisthesis patients aged older than 70 years.

Patient sample

Between January 2006 and December 2009, 73 patients aged 70 years or older with single-level degenerative spondylolisthesis requiring surgical treatment were included in this study.

Outcome measures

Clinical outcomes were assessed using the visual analog scale, Oswestry Disability Index, and Japanese Orthopedic Association scores. Radiographic outcomes included percentage of vertebral slippage, focal lordosis, and disc height.

Methods

The 73 patients were randomly assigned to two groups treated using surgical reduction (Group A, n=36) and fusion in situ (Group B, n=37). Both groups were followed up for an average of 33.2 months (range, 24–54 months). The clinical and radiographic outcomes were compared between the two groups.

Results

Surgical complications were similar in the two groups. The average operative time and blood loss during surgery did not insignificantly differ (p>.05) between the two groups. Spondylolisthesis, disc height, and focal lordosis were significantly improved postoperatively in both groups. There was no obvious difference in clinical outcomes, as assessed using the visual analog scale, Oswestry Disability Index, and Japanese Orthopedic Association scores, although the radiographic outcomes were considerably better in Group A than in Group B.

Conclusions

Posterior lumbar interbody fusion with pedicle screws fixation, with or without intraoperative reduction, provides good outcomes in the surgical treatment of aged patients with degenerative spondylolisthesis. Better radiological outcomes by intentional reduction do not necessarily indicate better clinical outcomes.