Percutaneous Juxtapedicular Cement Salvage of Failed Spinal Instrumentation? Institutional Experience and Cadaveric Biomechanical Study

BACKGROUND AND OBJECTIVES

Instrumented spinal fusion constructs sometimes fail because of fatigue loading, frequently necessitating open revision surgery. Favorable outcomes after percutaneous juxtapedicular cement salvage (perc-cement salvage) of failing instrumentation have been described; however, this approach is not widely known among spine surgeons , and its biomechanical properties have not been evaluated. We report our institutional experience with perc-cement salvage and investigate the relative biomechanical strength of this technique as compared with 3 other common open revision techniques.

METHODS

A retrospective chart review of patients who underwent perc-cement salvage was conducted. Biomechanical characterization of revision techniques was performed in a cadaveric model of critical pedicle screw failure. Three revision cohorts involved removal and replacement of hardware: (1) screw upsizing, (2) vertebroplasty, and (3) fenestrated screw with cement augmentation. These were compared with a cohort with perc-cement salvage performed using a juxtapedicular trajectory with the failed primary screw remaining engaged in the vertebral body.

RESULTS

Ten patients underwent perc-cement salvage from 2018 to 2022 to address screw haloing and/or endplate fracture threatening construct integrity. Pain palliation was reported by 8/10 patients. Open revision surgery was required in 4/10 patients, an average of 8.9 months after the salvage procedure (range 6.2-14.7 months). Only one revision was due to progressive hardware dislodgement. The remainder avoided open revision surgery through an average of 1.9 years of follow-up. In the cadaveric study, there were no significant differences in pedicle screw pullout strength among any of the revision cohorts.

CONCLUSION

Perc-cement salvage of failing instrumentation is reasonably efficacious. The technique is biomechanically noninferior to other revision strategies that require open surgery for removal and replacement of hardware. Open revision surgery may be avoided by perc-cement salvage in select cases.

Developing an Automated Registry (Autoregistry) of Spine Surgery Using Natural Language Processing and Health System Scale Databases

BACKGROUND AND OBJECTIVES

Clinical registries are critical for modern surgery and underpin outcomes research, device monitoring, and trial development. However, existing approaches to registry construction are labor-intensive, costly, and prone to manual error. Natural language processing techniques combined with electronic health record (EHR) data sets can theoretically automate the construction and maintenance of registries. Our aim was to automate the generation of a spine surgery registry at an academic medical center using regular expression (regex) classifiers developed by neurosurgeons to combine domain expertise with interpretable algorithms.

METHODS

We used a Hadoop data lake consisting of all the information generated by an academic medical center. Using this database and structured query language queries, we retrieved every operative note written in the department of neurosurgery since our transition to EHR. Notes were parsed using regex classifiers and compared with a random subset of 100 manually reviewed notes.

RESULTS

A total of 31 502 operative cases were downloaded and processed using regex classifiers. The codebase required 5 days of development, 3 weeks of validation, and less than 1 hour for the software to generate the autoregistry. Regex classifiers had an average accuracy of 98.86% at identifying both spinal procedures and the relevant vertebral levels, and it correctly identified the entire list of defined surgical procedures in 89% of patients. We were able to identify patients who required additional operations within 30 days to monitor outcomes and quality metrics.

CONCLUSION

This study demonstrates the feasibility of automatically generating a spine registry using the EHR and an interpretable, customizable natural language processing algorithm which may reduce pitfalls associated with manual registry development and facilitate rapid clinical research.

Carbon fiber-reinforced PEEK spinal implants for primary and metastatic spine tumors: a systematic review on implant complications and radiotherapy benefits

OBJECTIVE

By minimizing imaging artifact and particle scatter, carbon fiber-reinforced polyetheretherketone (CF-PEEK) spinal implants are hypothesized to enhance radiotherapy (RT) planning/dosing and improve oncological outcomes. However, robust clinical studies comparing tumor surgery outcomes between CF-PEEK and traditional metallic implants are lacking. In this paper, the authors performed a systematic review of the literature with the aim to describe clinical outcomes in patients with spine tumors who received CF-PEEK implants, focusing on implant-related complications and oncological outcomes.

METHODS

A systematic review of the literature published between database inception and May 2022 was performed in accordance with the 2020 Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. The PubMed database was queried using the terms "carbon fiber" and "spine" or "spinal." The inclusion criteria were articles that described patients with CF-PEEK pedicle screw fixation and had a minimum of 5 patients. Case reports and phantom studies were excluded.

RESULTS

This review included 11 articles with 326 patients (237 with CF-PEEK-based implants and 89 with titanium-based implants). The mean follow-up period was 13.5 months, and most tumors were metastatic (67.1%). The rates of implant-related complications in the CF-PEEK and titanium groups were 7.8% and 4.7%, respectively. The rate of pedicle screw fracture was 1.7% in the CF-PEEK group and 2.4% in the titanium group. The rates of reoperation were 5.7% (with 60.0% because of implant failure or junctional kyphosis) and 4.8% (all because of implant failure or junctional kyphosis) in the CF-PEEK and titanium groups, respectively. When reported, 72.5% of patients received postoperative RT (41.0% stereotactic body RT, 30.8% fractionated RT, 25.6% proton, 2.6% carbon ion). Four articles suggested that implant artifact was reduced in the CF-PEEK group. Local recurrence occurred in 14.4% of CF-PEEK and 10.7% of titanium-implanted patients.

CONCLUSIONS

While CF-PEEK harbors similar implant failure rates to traditional metallic implants with reduced imaging artifact, it remains unclear whether CF-PEEK implants improve oncological outcomes. This study highlights the need for prospective, direct comparative clinical studies.

Radiation Exposure in Posterior Lumbar Fusion: A Comparison of CT Image-Guided Navigation, Robotic Assistance, and Intraoperative Fluoroscopy

STUDY DESIGN

Retrospective clinical review.

OBJECTIVE

To assess the use of intraoperative computed tomography (CT) image-guided navigation (IGN) and robotic assistance in posterior lumbar surgery and their relationship with patient radiation exposure and perioperative outcomes.

METHODS

Patients ≥18 years old undergoing 1- to 2-level transforaminal lateral interbody fusion in 12-month period were included. Chart review was performed for pre- and intraoperative data on radiation dose and perioperative outcomes. All radiation doses are quantified in milliGrays (mGy). Univariate analysis and multivariate logistic regression analysis were utilized for categorical variables. One-way analysis of variance with post hoc Tukey test was used for continuous variables.

RESULTS

A total of 165 patients were assessed: 12 IGN, 62 robotic, 56 open, 35 fluoroscopically guided minimally invasive surgery (MIS). There was a lower proportion of women in open and MIS groups (P = .010). There were more younger patients in the MIS group (P < .001). MIS group had the lowest mean posterior levels fused (P = .015). Total-procedure radiation, total-procedure radiation/level fused, and intraoperative radiation was the lowest in the open group and highest in the MIS group compared with IGN and robotic groups (all P < .001). Higher proportion of robotic and lower proportion of MIS patients had preoperative CT (P < .001). Estimated blood loss (P = .002) and hospital length of stay (P = .039) were lowest in the MIS group. Highest operative time was observed for IGN patients (P < .001). No differences were observed in body mass index, Charlson Comorbidity Index, and postoperative complications (P = .313, .051, and .644, respectively).

CONCLUSION

IGN and robotic assistance in posterior lumbar fusion were associated with higher intraoperative and total-procedure radiation exposure than open cases without IGN/robotics, but significantly less than MIS without IGN/robotics, without differences in perioperative outcomes. Fluoro-MIS procedures reported highest radiation exposure to patient, and of equal concern is that the proportion of total radiation dose also applied to the surgeon and operating room staff in fluoro-MIS group is higher than in IGN/robotics and open groups.

Posterior Dynamic Stabilization of the Lumbar Spine Review of Biomechanical and Clinical Studies

Fusion and rigid instrumentation have been the mainstay for the surgical treatment of degenerative diseases of the spine for many years. Dynamic stabilization provides a theoretical advantage of decreased biomechanical stress on adjacent spinal segments and decreased fatigue failure of implants. Artificial discs provide an alternative treatment and have been well-studied in the literature. Another technology that is currently used in Europe but rarely in the USA is flexible rods attached to pedicle screws instead of rigid rods or bone fusion. We performed a literature review of the current systems of flexible rod stabilization, while also considering range of motion, loading characteristics, and infection rates.

Older Age and Leg Pain Are Good Predictors of Pain and Disability Outcomes in 2710 Patients Who Receive Lumbar Fusion

BACKGROUND

Identifying appropriate candidates for lumbar spine fusion is a challenging and controversial topic. The purpose of this study was to identify baseline characteristics related to poor/favorable outcomes at 1 year for a patient who received lumbar spine fusion.

QUESTIONS/PURPOSES

The aims of this study were to describe baseline characteristics of those who received lumbar surgery and to identify baseline characteristics from a spine repository that were related to poor and favorable pain and disability outcomes for patient who received lumbar fusion (with or without decompression), who were followed up for 1 full year and discriminate predictor variables that were either or in contrast to prognostic variables reported in the literature.

METHODS

This study analyzed data from 2710 patients who underwent lumbar spine fusion. All patient data was part of a multicenter, multi-national spine repository. Ten relatively commonly captured data variables were used as predictors for the study. Univariate/multivariate logistic regression analyses were run against outcome variables of pain/disability.

RESULTS

Multiple univariate findings were associated with pain/disability outcomes at 1 year including age, previous surgical history, baseline disability, baseline pain, baseline quality of life scores, and leg pain greater than back pain. Notably significant multivariate findings for both pain and disability include older age, previous surgical history, and baseline mental summary scores, disability, and pain.

CONCLUSION

Leg pain greater than back pain and older age may yield promising value when predicting positive outcomes. Other significant findings may yield less value since these findings are similar to those that are considered to be prognostic regardless of intervention type.

Lumbar laminectomy and fusion with routine local application of vancomycin powder: decreased infection rate in instrumented and non-instrumented cases

OBJECTIVE

Wound infections are one of the most common and potentially devastating complications of spinal surgery. Intra-wound application of vancomycin powder has been shown to lower the infection risk following posterior instrumented fusion, but little evidence supports use in other spinal operations. The goal of this study is to assess the efficacy of vancomycin powder for lumbar laminectomy and fusion, both instrumented and non-instrumented.

METHODS

All cases of lumbar laminectomy and posterior fusion (with or without pedicle screw fixation) by a single surgeon were reviewed from 2007 to 2011. Routine application of 1g vancomycin powder was started in August 2009. Baseline characteristics and operative data were compared between untreated patients and those who received vancomycin powder. Rates of wound infection were compared for all fusions, and then separately for instrumented and non-instrumented cases.

RESULTS

253 patients underwent lumbar laminectomy and fusion between 2007 and 2011. Baseline and operative variables were similar between untreated patients (n=97) and those who received vancomycin powder (n=156). Patients were followed for at least one year. The infection rate fell significantly following introduction of vancomycin powder (from 11% to 0%, p=0.000018). Subgroup analysis revealed significant infection reduction for both instrumented cases (from 12% to 0%, p=0.000806) and non-instrumented cases (from 10% to 0%, p=0.0496). No complications attributable to vancomycin powder were identified.

CONCLUSION

Local vancomycin powder appears to lower the risk of wound infection following lumbar laminectomy and fusion, both instrumented and non-instrumented. Further studies are needed to optimize dosing of vancomycin powder, assess long-term safety and efficacy, and evaluate use in other spinal operations.

Large cell neuroendocrine carcinoma of the lung metastatic to the cauda equina

BACKGROUND CONTEXT

Large cell neuroendocrine carcinoma of the lung is an aggressive tumor with unique histopathological features. It is not known to metastasize to the spine.

PURPOSE

To report a metastatic case of this rare tumor to the cauda equina.

STUDY DESIGN

Case report.

METHODS

Retrospective case review and review of the literature.

RESULTS

The authors report a rare case of a large cell neuroendocrine lung metastasis to the lumbar spine, causing right foot drop. Magnetic resonance imaging revealed a heterogeneously enhancing intradural extramedullary mass at L2/L3 level compressing the surrounding nerve roots. During surgery, the identified nerve roots were encased by the tumor, and the dissection was tedious. Postoperatively, the patient reported significantly improved back pain and he had severe foot weakness. The functional outcome was poor because the patient lost entirely his foot function; however, his back pain improved significantly after surgery.

CONCLUSIONS

This is the first published study in which the authors described a metastasis of a rather uncommon lung cancer to the cauda equina. When a lesion of the cauda equina presents with a rapid progressive neurological deficit, leptomeningeal metastasis should be in the differential diagnosis.

Metameric thoracic lesion: report of a rare case and a guide to management

Metameric lesions of the spine are rare. The authors present a case of patient with a complex metameric vascular lesion of the thoracic spine and describe a management strategy for this entity.

Minimally Invasive Atlantoaxial Fusion

BACKGROUND

C1–C2 fusion has significantly advanced from predominantly wiring/cable modalities to more biomechanically stable screw-rod techniques. Minimally invasive surgical techniques represents the most recent modification of atlantoaxial fixation. The indications, rationale, and surgical technique of this novel procedure are described.

METHODS

Six patients requiring C1–C2 fusion (5 type II odontoid fractures and 1 os odontoideum) underwent minimally invasive C1–C2 fusion over a 2-year period. The cohort consisted of 5 men and 1 woman with a mean age of 51 years (age range, 39–64 y). All 6 patients underwent bilateral segmental atlantoaxial fixation using an expandable tubular retractor.

RESULTS

The mean follow-up time was 32 months (age range, 24–46 mo) There were no intraoperative complications, and the mean estimated blood loss was 100 mL. Solid fusion was achieved in all 6 patients, without pathological motion on dynamic studies. Postoperative computed tomographic images showed no hardware malposition in the scanned patients (4 of the 6 patients).

CONCLUSIONS

Placement of C1 and C2 instrumentation using minimally invasive techniques is technically feasible. Because the instrumentation and the means of obtaining arthrodesis do not differ substantively from the standard approach, we would not anticipate long-term results to be different from those of an open procedure, apart from the approach-related morbidity.

Unique features of herniated discs at the cervicothoracic junction: clinical presentation, imaging, operative management, and outcome after anterior decompressive operation in 10 patients

OBJECTIVE

Disc herniations at the C7-T1 level are unusual (4% of all herniated cervical discs) and are often incorrectly diagnosed because of unusual neurological findings and suboptimal imaging studies. Furthermore, the anterior approach may be problematic because the manubrium and slope of the vertebral bodies away from the surgeon obscures the end plates. The recurrent laryngeal nerve and the thoracic duct may be injured by respective right- or left-sided approaches. A posterior approach to this level has, therefore, been advocated, but results of C7-T1 herniations treated anteriorly have not been specifically addressed in the literature. We, therefore, reviewed our experience in the operative management of patients undergoing single level anterior cervical discectomy and fusion at the C7-T1 interspace for the 10 years ending June 2004 with regard to clinical presentation, imaging, problems of operative exposure, and neurological outcome.

METHODS

Of 268 patients with single level anterior cervical discectomy and fusions (ACDFs), 10 (3.7%) had C7-T1 disc herniations. We retrospectively reviewed the medical records, operative reports, and imaging studies of these 10 patients.

RESULTS

All patients presented with C8 motor deficit without myelopathy. The operation was carried out through an anterior approach with a skin incision 3 cm above the clavicle. Visualization of the C7-T1 disc space was achieved in all without difficulty. Eight of 10 patients are neurologically intact.

CONCLUSION

The C7-T1 disc herniates laterally because of the absence of Luschka joints at this level. Central herniation with myelopathy is rare. An anterior approach was easily accomplished in all patients. Recovery of motor function was related to duration and severity of preoperative deficit.

Anesthesia for an adult with mucopolysaccharidosis I

We describe the anesthetic management difficulties of a man with mucopolysaccharidosis I. We also briefly review the anesthesia literature related to this disease.

Minimally Invasive Atlantoaxial Fixation with a Polyaxial Screw-rod Construct: Technical Case Report

Objective and Importance:

Posterior C1–C2 fusion with polyaxial screw and rod fixation has become an accepted means of atlanto-axial stabilization. We describe a novel technique for minimally invasive placement of C1 lateral mass screws and C2 pedicle screws for polyaxial screw-rod stabilization.

Clinical Presentation:

The patient presented with a history of chronic neck pain, as well as a 6-month history of weakness and paresthesias involving her left hand. An Os Odontoideum was present on computed tomographic imaging of the cervical spine. Significant instability was noted on flexion-extension imaging, and magnetic resonance imaging demonstrated mild T2 signal change within the spinal cord.

Technique:

Under fluoroscopic guidance, serial dilators were passed through a 2.5 cm paramedian skin incision to allow placement of an expandable tubular retractor. The exposure was centered on the C2 lateral mass. After expansion of the retractor and further subperiosteal dissection, the C1 and C2 lateral masses were visible permitting placement of a polyaxial screw rod construct. This procedure was carried out bilaterally.

Conclusion:

Placement of C1 lateral mass and C2 pedicle screws using minimally invasive techniques is technically feasible.

Bowel injury as a complication of microdiscectomy: case report and literature review

Intestinal injury is a rare complication of lumbar disc surgery, resulting from inadvertent penetration of the anterior annulus fibrosus and anterior longitudinal ligament. Patients typically complain of abdominal pain and distention developing over the course of several days. Imaging with plain upright chest radiographs or abdominal computed tomography may demonstrate free air in the abdominal cavity. We report a case of intestinal perforation after microscopic lumbar discectomy and present the diagnostic postoperative imaging. In addition, we review the relevant literature and discuss techniques that may be employed to avoid this complication.

Endoscopically assisted transoral-transpharyngeal approach to the craniovertebral junction

OBJECTIVE

We describe a series of seven consecutive patients treated with endoscopically assisted transoral surgery for decompression of high cervical and clival abnormalities.

METHODS

Seven endoscopically assisted transoral procedures were performed at the University of Florida from September 1999 to April 2000 for irreducible compression at the cervicomedullary junction. The abnormalities encountered were primary basilar invagination from congenital craniovertebral junction malformation (two cases), irreducible rheumatoid cranial settling (one case), secondary basilar invagination caused by migration of odontoid fracture fragments (one case), pseudogout granulation mass (one case), clivus chordoma (one case), and Chiari malformation with associated basilar invagination (one case).

RESULTS

Successful decompression was achieved in all seven patients. There were no adverse neurological sequelae. One patient died from a perioperative myocardial infarction. At a mean clinical follow-up of 6.16 months, neurological status was noted to be stable or improved in all remaining patients.

CONCLUSION

Endoscopically assisted transoral surgery represents an emerging alternative to standard microsurgical techniques for transoral approaches to the anterior cervicomedullary junction. Used in conjunction with intraoperative fluoroscopy, it provides a safe method for anterior decompression of the cervicomedullary junction without the need for extensive soft palate splitting, hard palate resection, or extended maxillotomy. Experience is required with greater numbers of patients and long-term follow-up to further validate this promising technique.