Revision surgery in cervical spine

Evaluation of the efficacy of posterior hemivertebrectomy combined with two or more segments fusion

BACKGROUND

Although early hemivertebra (HV) resection and short fusion (within 4 segments) have been successful in treating congenital HV, there is limited research comparing the outcomes of the shortest-segment fusion (2 segments) versus 3 or 4 segments, particularly in young children. To evaluate the efficacy of posterior hemivertebrectomy combined with two or more segments fusion in children under the age of 10 years with a solitary simple lower thoracic or lumbar HV (T8-L5).

METHODS

This retrospective study included patients under the age of 10 with lower thoracic or lumbar solitary simple HV who underwent hemivertebra resection (HVR) and transpedicular short fusion and were divided into HV ± 1 group (2 segment fusion) and HV ± 2 group (3 or 4-segment fusion). The study recorded preoperative, postoperative (1 week), and the latest follow-up radiographic parameters and complications. The results of the coronal and sagittal planes were analyzed, and the main curve, segmental scoliosis curve, compensatory scoliosis curve, segmental kyphosis curve, and trunk shift were compared.

RESULTS

The study included 35 patients (15 in the HV ± 1 group and 20 in the HV ± 2 group) with a mean age of 5.26 ± 2.31 years and a mean follow-up of 22.54 months (12-68). The mean preoperative Cobb angle was 32.66° ± 7.339° (HV ± 1) and 29.31°±6.642° (HV ± 2). The final Cobb angle was 10.99°± 7.837° (HV ± 1) and 8.22° ± 4.295° (HV ± 2). The main curve corrected by 72% (HV ± 1), 75% (HV ± 2) postoperatively and 67% (HV ± 1), 72% (HV ± 2) at the final follow-up (P > 0.05). There were no significant differences in the correction of the segmental scoliosis curve, compensatory scoliosis curve, segmental kyphosis curve, and trunk shift between the HV ± 1 and HV ± 2 groups (P > 0.05). The unplanned reoperation rate for HV in the thoracolumbar region (T11-L2) is significantly higher (P = 0.038).

CONCLUSION

In the context of solitary simple lower thoracic or lumbar HV (T8-L5), HV ± 1 segment fusion suffices and yields comparable correction outcomes in the midterm period when compared to HV ± 2. The reoperation rate exhibited a statistically significant increase in the thoracolumbar region.

The Incidence, Changes and Treatments of Cervical Deformity After Infection and Inflammation

A healthy cervical spine with normal movement is the basis of many daily activities and is essential for maintaining a good quality of life. However, the alignment, fusion, and structure of the cervical spine can change for various reasons, leading to cervical deformity, mainly kyphosis. Approximately 5%‒20% of spinal infections in the cervical spine cause cervical deformity. The deformity can recover early; however, the disease's long-term existence or the continuous action of abnormal stress may lead to intervertebral fusion and abnormal osteophytes. Many gaps and controversies exist regarding infectious cervical deformities, including a lack of clear definitions and an acceptable classification system thereby requiring further research. Moreover, there is no consensus on the indications for postinfectious cervical deformity associated with <i>Mycobacterium tuberculosis</i>, <i>Staphylococcus aureus</i>, and Brucellosis. Therefore, we reviewed and discussed the incidence, clinical manifestations, changes, and treatment of infectious and inflammatory secondary cervical deformities from common to rare to provide a theoretical basis for clinical decision-making.

Incidence and local risk factors of infection after anterior sub-axial cervical spine surgery: retrospective database analysis of 4897 consecutive procedures

INTRODUCTION

The anterior cervical spine approach is safe and effective in many cervical spine pathologies. It is considered one of the most common approaches in spine surgery. Postoperative infections after anterior cervical surgery are rare but serious.

MATERIALS AND METHODS

This study is a retrospective database analysis. In this study, the incidence, and the local risk factors of postoperative infection after anterior-only sub-axial cervical spine surgery in a high-volume spine center were analyzed. The data of patients operated in a teaching hospital is electronically stored in a comprehensive medical database program. Postoperative infection after anterior cervical surgery from C2 to C7 was calculated and analyzed. In the study period, 4897 patients were operated. Twenty-four infections after a primary aseptic operation were detected. Independent local risk factors were estimated.

RESULTS

Postoperative infection occurred in 24/4897 patients (0.49%). The incidence of infection after cervical trauma was 3% (7/229), after spinal cord injury 4.3% (2/46), with myelopathy 1.98% (11/556), and after revision surgery 1.25% (7/560). The incidence showed a significant increase (p = 0.00, 0.01, 0.02). In 14 of the postoperatively infected patients (58.3%) an oesophageal injury was diagnosed. Odds ratios (OR) with a confidence interval (CI) of 95% was calculated. Independent risk factors for the postoperative infections were: Cervical trauma (OR 8.59, 95% CI 3.52-20.93), revision surgery (OR 3.22, 95% CI 1.33-7.82), The presence of cervical myelopathy (OR 6.71, 95% CI 2.99-15.06), and spinal cord injury (OR 9.33, 95% CI 2.13-40.83).

CONCLUSIONS

Postoperative infection after anterior cervical surgery is low (0.49%). In addition to the general risk factor for infection, the local risk factors are trauma, myelopathy, spinal cord injury, and revision surgeries. In the case of postoperative infection, an oesophageal injury should be excluded.

Reliability and Utility of Various Methods for Evaluation of Bone Union after Anterior Cervical Discectomy and Fusion

Most surgical procedures performed on account of degenerative disease of the cervical spine involve a discectomy and interbody fixation. Bone fusion at the implant placement site is evaluated post-operatively. It is agreed that computed tomography is the best modality for assessing bone union. We evaluated the results obtained with various methods based solely on conventional radiographs in the same group of patients and compared them with results obtained using a method that is a combination of CT and conventional radiography, which we considered the most precise and a reference method. We operated on a total of 170 disc spaces in a group of 104 patients. Fusion was evaluated at 12 months after surgery with five different and popular classifications based on conventional radiographs and then compared with the reference method. Statistical analyses of test accuracy produced the following classification of fusion assessment methods with regard to the degree of consistency with the reference method, in descending order: (1) bone bridging is visible on the anterior and/or posterior edge of the operated disc space on a lateral radiograph; (2) change in the value of Cobb's angle for a motion segment on flexion vs. extension radiographs (threshold for fusion vs. pseudoarthrosis is 2°); (3) change in the interspinous distance between process tips on flexion vs. extension radiographs (threshold of 2 mm); (4) change in the value of Cobb's angle of a motion segment (threshold of 4°); (5) change in the interspinous distance between process bases on flexion vs. extension radiographs (threshold of 2 mm). When bone union is evaluated on the basis on radiographs, without CT evidence, we suggest using the "bone bridging" criterion as the most reliable commonly used approach to assessing bone union.

Barbed Suture versus Interrupted Suture in Posterior Cervical Spine Surgery: Are They Equivalent?

Introduction

Posterior cervical spine approaches have been associated with increased rates of wound complications compared to anterior approaches. While barbed suture wound closure for lumbar spine surgery has been shown to be safe and efficacious, there is no literature regarding its use in posterior cervical spine surgery. In a cohort of patients undergoing elective posterior cervical spine surgery, we sought to compare postoperative complication rates between barbed and traditional interrupted suture closure.

Methods

A retrospective review of demographics, past medical history, and operative and postoperative variables collected from a prospective registry between July 1, 2016, and June 30, 2020 was undertaken. All patients 18 years old and above undergoing elective posterior cervical fusion were included. The primary outcome of interest was wound complications, including surgical site infection (SSI), dehiscence, or hematoma. In addition, numerical rating scale (NRS) neck pain (NP), NRS arm pain (AP), Neck Disability Index (NDI), and operative time were collected. A variety of statistical tests were used to compare the two suture groups.

Results

Of 117 patients undergoing posterior cervical fusion, 89 (76%) were closed with interrupted suture and 28 (24%) with barbed suture. The interrupted cohort were more likely to have >1 comorbidity (p<0.001), diabetes mellitus (p=0.013), and coronary artery disease (p=0.002). No difference in postoperative wound complications between interrupted/barbed sutures was observed after univariate (OR 1.07, 95% CI: 0.27-4.25, p=0.927) and multivariable logistic regression analysis (OR 0.77, 95% CI: 0.15-4.00, p=0.756). Univariate logistic regression revealed no differences in achieving minimal clinically important difference (MCID) NRS-NP (OR 0.73, 95% CI: 0.28-1.88, p=0.508) or NRS-AP (OR 0.68, 95% CI: 0.25-1.90, p=0.464) at 3 months between suture groups. The interrupted suture group was less likely to achieve MCID NDI at 3 months (OR 0.29, 95% CI: 0.11-0.80, p=0.016).

Conclusions

Barbed suture closure in posterior cervical spine surgery does not lead to higher rates of postoperative wound complications/SSI compared to traditional interrupted fascial closure.

Early Reoperation Rates and Its Risk Factors after Instrumented Spinal Fusion Surgery for Degenerative Spinal Disease: A Nationwide Cohort Study of 65,355 Patients

Reoperation is a major concern in spinal fusion surgery for degenerative spinal disease. Earlier reported reoperation rates were confined to a specific spinal region without comprehensive analysis, and their prediction models for reoperation were not statistically validated. Our study aimed to present reasonable base rates for reoperation according to all possible risk factors and build a validated prediction model for early reoperation. In our nationwide population-based cohort study, data between 2014 and 2016 were obtained from the Korean National Health Insurance claims database. Patients older than 19 years who underwent instrumented spinal fusion surgery for degenerative spinal diseases were included. The patients were divided into cases (patients who underwent reoperation) and controls (patients who did not undergo reoperation), and risk factors for reoperation were determined by multivariable analysis. The estimates of all statistical models were internally validated using bootstrap samples, and sensitivity analyses were additionally performed to validate the estimates by comparing the two prediction models (models for 1st-year and 3rd-year reoperation). The study included 65,355 patients: 2939 (4.5%) who underwent reoperation within 3 years after the index surgery and 62,146 controls. Reoperation rates were significantly different according to the type of surgical approach and the spinal region. The third-year reoperation rates were 5.3% in the combined lumbar approach, 5.2% in the posterior lumbar approach, 5.0% in the anterior lumbar approach, 3.0% in the posterior thoracic approach, 2.8% in the posterior cervical approach, 2.6% in the anterior cervical approach, and 1.6% in the combined cervical approach. Multivariable analysis identified older age, male sex, hospital type, comorbidities, allogeneic transfusion, longer use of steroids, cages, and types of surgical approaches as risk factors for reoperation. Clinicians can conduct comprehensive risk assessment of early reoperation in patients who will undergo instrumented spinal fusion surgery for degenerative spinal disease using this model.

PEEK versus titanium-coated PEEK cervical cages: fusion rate

BACKGROUND

Anterior cervical discectomy and fusion (ACDF) is one of the most commonly performed procedures for degenerative cervical disease. The evaluation of fusion status is still not fully standardized, and a variety of measurement methods are used. This study presents our own evaluation of fusion by comparing two types of implants.

METHODS

A total of 170 disc spaces were operated on in 104 patients using PEEK (polyetheretherketone) cages and titanium-coated (TC) PEEK cages. Patients were assigned to a specific implant using a randomisation table. Fusion status was evaluated based on functional radiographs and CT scans obtained at 12 months post-surgery. Multivariate mixed-effects logistic regression models were performed to assess the association of type of implant with different fusion rates.

RESULTS

At 12 months post-surgery, CT scans were performed in 86 patients (a total of 144 disc spaces) and conventional radiographs were obtained in 102 (a total of 166 disc spaces). Complete fusion was demonstrated in 101 cases (71.1%), partial fusion in 43 cases (29.9%). There were no cases of absence of fusion. A total of 85 PEEK cages (59%) and 59 TC-PEEK cages (41%) were implanted. For PEEK cages, complete fusion was seen in 75 (88.2%) disc spaces, compared to 26 (44.1%) achieved with TC-PEEK cages. A significantly higher proportion of complete fusions (B = 15.58; P < 0.0001) after 12 months was observed with PEEK implants compared to TC-PEEK implants.

CONCLUSION

Complete fusion was noted at 12 months post-surgery significantly more frequently with PEEK implants compared to TC-PEEK implants.

Complex Revision Surgery for Cervical Deformity or Implant Failure

Postoperative cervical deformity sometimes occurs in the short or long term after primary surgery for cervical disorders related to the degenerative aging spine, neoplastic etiologies, hemodialysis, infection, inflammation, trauma, etc. Cervical kyphosis after posterior decompression surgery, such as laminectomy or laminoplasty, is a common problem for spine surgeons. However, revision surgery for cervical deformity is definitely one of the most challenging areas for spine surgeons. There is no doubt that surgery for cervical deformity carries a high risk of surgery-related complications that might result in aggravation of health-related quality of life. Revision surgery is even more challenging. Hence, spine surgeons need to assess carefully the overall severity of the underlying condition before revision surgery, and try to refine the surgical strategy to secure safe surgery. Needless to say, spine surgeons are now facing great challenges in making spine surgery a much more reliable and convincing entity.

Anterior Reconstruction Techniques for Cervical Spine Deformity

Cervical spine deformity is an uncommon yet severely debilitating condition marked by its heterogeneity. Anterior reconstruction techniques represent a familiar approach with a range of invasiveness and correction potential-including global or focal realignment in the sagittal and coronal planes. Meticulous preoperative planning is required to improve or prevent neurologic deterioration and obtain satisfactory global spinal harmony. The ability to perform anterior only reconstruction requires mobility of the opposite column to achieve correction, unless a combined approach is planned. Anterior cervical discectomy and fusion has limited focal correction, but when applied over multiple levels there is a cumulative effect with a correction of approximately 6° per level. Partial or complete corpectomy has the ability to correct sagittal deformity as well as decompress the spinal canal when there is anterior compression behind the vertebral body. If pathoanatomy permits, a hybrid discectomy-corpectomy construct is favored over multilevel corpectomies. The anterior cervical osteotomy with bilateral complete uncinectomy may be necessary for angular correction of fixed cervical kyphosis, and is particularly useful in the midcervical spine. A detailed understanding of the patient's local anatomy, careful attention to positioning, and avoiding long periods of retraction time will help prevent complications and iatrogenic injury.