Image-guided pedicle screws using intraoperative cone-beam CT and navigation. A cost-effectiveness study.

Image-guided surgery using intraoperative cone-beam CT and navigation improves screw placement accuracy rates. However, this technology is associated with high acquisition costs. The aim of this study is to evaluate the costs of revision surgery from symptomatic pedicle screw malposition to justify whether the costs of acquiring intraoperative navigation justify the expected benefits. This is a retrospective cost-effectiveness analysis of consecutive patients who had pedicle screw instrumentation using intraoperative cone-beam CT and navigation compared with patients who underwent freehand pedicle screw instrumentation at our institution over 4 years. The costs associated with revision surgery for symptomatic pedicle screw malposition (excess length of stay, intensive care, theatre time, implants and additional outpatient appointments) were calculated. A total of 19 patients had symptomatic screw malpositioning requiring revision surgery. None of these patients had screws inserted under navigation. Revision surgery accounted for an extra 304 bed days and an additional 97 h theatre time. The total extra spent over 4 years was £464,038. When compared to the costs of revision surgery for screw malpositioning, it was cost neutral to acquire and maintain this technology. Intraoperative image-guided surgery reduces reoperation rates for symptomatic screw malposition and is cost-effective in high volume centers with improved patients outcomes. High acquisition and maintenance cost of such technologies is economically justifiable.

The incidence of new onset sacroiliac joint pain following lumbar fusion.

BACKGROUND: The sacroiliac joint (SIJ) can be a new source of pain following lumbar fusion. The aim of this study was to identify the incidence of and predisposing factors for new onset SIJ pain following successful lumbar fusion. METHODS: We review our series of 317 patients who underwent spinal fusion in the past 5 years to identify patients who developed new onset SIJ pain. All patients had a minimum 12 months follow up. Diagnostic criteria for SIJ pain were: New onset pain localised to lower lumbar region and buttocks, ≥2 positive provocative tests of SIJ and pain relief of >70% achieved from SIJ block. RESULTS: There were 38 patients who developed new SIJ pain following fusion with an overall incidence of 12.0%. The average time to new onset symptoms was 22 months. Of the 38 patients, 57.9% had fusion to sacrum. The incidence of SIJ pain in patients who had fusion extending into sacrum was 12.6% vs. 11.2% in those who had not. The incidence of SIJ pain was 11.1% with 1-level fusion, 12.0% with 2-level fusion, 12.9% with 3-level fusion and 14.0% with equal or more than 4-level fusion. CONCLUSIONS: New onset SIJ pain can arise following spinal fusion. We have not found a higher frequency of SIJ pain in patients with fusion extending to sacrum or longer spinal construct.

Minimally invasive stabilization for thoracolumbar and lumbar fractures: a comparative study with short segment open Schanz screw constructs.

BACKGROUND: Analysis was performed of two patient cohorts who underwent fixation without fusion for unstable thoracolumbar and lumbar fractures: (I) minimally invasive surgery (MIS) group using combined monoaxial-polyaxial pedicle screws inserted percutaneously; (II) open surgery (OS) group using Schanz screw constructs. Our aim was to compare radiographic and clinical indices of the 'gold standard' of open Schanz screw to MIS monoaxial-polyaxial screw constructs. METHODS: There were 13 patients in the MIS group and 19 in the OS group. Primary outcomes were the correction of fracture angulation and percentage loss of reduction until fracture union. Patient demographics, fracture classification, perioperative data and complications were also collected. RESULTS: There was no significant difference in cohorts when comparing demographics and fracture classification. Operative time was 50 minutes less and haemoglobin drop was 9 g/L less in the MIS group. Radiation exposure was significantly higher in the MIS group. Pre-operatively, the mean kyphotic angle was 22° in the MIS and 16° in the OS group. Both groups achieved similar on-table correction. On immediate postoperative erect radiographs, the MIS group lost 15% of correction vs. 55% in the OS group. At final follow-up, both groups had a further loss of position, but significantly higher in the OS group (28% vs. 96%). CONCLUSIONS: Combined polyaxial-monoaxial screw MIS constructs demonstrate favorable radiological and clinical outcomes for treatment of unstable thoracolumbar and lumbar fractures. Our study also demonstrates higher rates of radiological collapse in the OS cohort.

Minimal invasive surgical algorithm for revision lumbar spinal surgery.

BACKGROUND: Revision spinal surgery following primary spinal fusion procedure occurs in 8-45% of cases. Reasons for revision include recurrence of stenosis, non-union, implant failure, infection, adjacent segment degeneration and flat back fusion. With the rise in elective lumbar fusion rates, it is expected that the rate for revision spinal surgery will also increase with time. The use of minimal invasive surgical techniques for revision spinal surgery is controversial. Careful patient and technique selection is important in achieving satisfactory outcome in revision spinal surgery. METHODS: This article outlines our algorithm for selecting the appropriate minimally invasive surgery (MIS) techniques for revision lumbar spinal surgery. Surgical options range from decompression employing MIS techniques to open osteotomies, but the optimal approach comes down to two deciding factors: (I) nature of previous surgery and (II) spinopelvic parameters. RESULTS: Representative revision cases managed using MIS techniques based on proposed revision algorithm are presented. CONCLUSIONS: Our proposed algorithm provides surgeons with a systematic approach in selecting the appropriate combination of MIS techniques for revision lumbar spinal surgery based on pathology and sagittal alignment.

Minimally invasive stabilization of the fractured ankylosed spine: a comparative case series study.

BACKGROUND: To compare the outcome of minimally invasive fracture stabilization to traditional open methods in the thoracolumbar region in patients with an ankylosing disorder of the spine. METHODS: A prospective, ethics-approved database (Spine Tango) at a tertiary referral center was retrospectively reviewed for results of surgery on fractures of the ankylosed thoracolumbar spine. These were then split by surgical technique into two cohorts: minimally invasive surgical fixation (MIS group) or standard open surgery (open group). RESULTS: We identified 17 patients who presented with fractures in an ankylosed spine from 2010 to 2017. MIS fixation was performed on 10 and open surgery and fixation on 7. Average age in the MIS group was older than the traditional cohort. There was no difference in the average number of levels stabilized (open =6.9, MIS =7). There was a shorter duration in the operative time and a significant difference in blood loss in favor of the MIS group (P=0.00079). Radiation exposure time and dose were significantly higher in the MIS group (P=0.006). There were no cases of non-union, implant malposition or failure in either group. Two significant complications occurred with the death of one patient in the MIS group, and one death in the open group. CONCLUSIONS: The MIS technique for fractures of the ankylosed spine has shown an acceptable complication rate and good results comparable to open surgery for a high-risk patient population.

Traumatic subaxial cervical facet subluxation and dislocation: epidemiology, radiographic analyses, and risk factors for spinal cord injury.

BACKGROUND CONTEXT: Distractive flexion injuries (DFIs) of the subaxial cervical spine are major contributors to spinal cord injury (SCI). Prompt assessment and early intervention of DFIs associated with SCI are crucial to optimize patient outcome; however, neurologic examination of patients with subaxial cervical injury is often difficult, as patients commonly present with reduced levels of consciousness. Therefore, it is important to establish potential associations between injury epidemiology and radiographic features, and neurologic involvement. PURPOSE: The aims of this study were to describe the epidemiology and radiographic features of DFIs presenting to a major Australian tertiary hospital and to identify those factors predictive of SCI. The agreement and repeatability of radiographic measures of DFI severity were also investigated. STUDY DESIGN/SETTING: This is a combined retrospective case-control and reliability-agreement study. PATIENT SAMPLE: Two hundred twenty-six patients (median age 40 years [interquartile range = 34]; 72.1% male) who presented with a DFI of the subaxial cervical spine between 2003 and 2013 were reviewed. OUTCOME MEASURES: The epidemiology and radiographic features of DFI, and risk factors for SCI were identified. Inter- and intraobserver agreement of radiographic measurements was evaluated. METHODS: Medical records, radiographs, and computed tomography and magnetic resonance imaging scans were examined, and the presence of SCI was evaluated. Radiographic images were analyzed by two consultant spinal surgeons, and the degree of vertebral translation, facet apposition, spinal canal occlusion, and spinal cord compression were documented. Multivariable logistic regression models identified epidemiology and radiographic features predictive of SCI. Intraclass correlation coefficients (ICCs) examined inter- and intraobserver agreement of radiographic measurements. RESULTS: The majority of patients (56.2%) sustained a unilateral (51.2%) or a bilateral facet (48.8%) dislocation. The C6-C7 vertebral level was most commonly involved (38.5%). Younger adults were over-represented among motor-vehicle accidents, whereas falls contributed to a majority of DFIs sustained by older adults. Greater vertebral translation, together with lower facet apposition, distinguished facet dislocation from subluxation. Dislocation, bilateral facet injury, reduced Glasgow Coma Scale, spinal canal occlusion, and spinal cord compression were predictive of neurologic deficit. Radiographic measurements demonstrated at least a "moderate" agreement (ICC>0.4), with most demonstrating an "almost perfect" reproducibility. CONCLUSIONS: This large-scale cohort investigation of DFIs in the cervical spine describes radiographic features that distinguish facet dislocation from subluxation, and associates highly reproducible anatomical and clinical indices to the occurrence of concomitant SCI.

Most Cited Publications in Cervical Spine Surgery.

PURPOSE: The purpose of this study is to perform a citation analysis on the most frequently cited articles in the topic of cervical spine surgery and report on the top 100 most cited publication in this topic. METHODS: We used the Thomson Reuters Web of Science to search citations of all articles from 1945 to 2015 relevant to cervical spine surgery and ranked them according to the number of citations. The 100 most cited articles that matched the search criteria were further analyzed by number of citations, first author, journal, year of publication, country and institution of origin. RESULTS: The top 100 cited articles in the topic of cervical spine surgery were published from 1952-2011. The number of citations ranged from 106 times for the 100th paper to 1206 times for the top paper. The decade of 1990-1999 saw the most publications. The Journal of Spine published the most articles, followed by Journal of Bone and Joint Surgery America. Investigators from America authored the most papers and The University of California contributed the most publications. Cervical spine fusion was the most common topic published with 36 papers, followed by surgical technique and trauma. CONCLUSION: This article identifies the 100 most cited articles in cervical spine surgery. It has provided insight to the history and development in cervical spine surgery and many of which have shaped the way we practice today.

Operative Management of Lumbar Degenerative Disc Disease.

Lumbar degenerative disc disease is extremely common. Current evidence supports surgery in carefully selected patients who have failed non-operative treatment and do not exhibit any substantial psychosocial overlay. Fusion surgery employing the correct grafting and stabilization techniques has long-term results demonstrating successful clinical outcomes. However, the best approach for fusion remains debatable. There is some evidence supporting the more complex, technically demanding and higher risk interbody fusion techniques for the younger, active patients or patients with a higher risk of non-union. Lumbar disc arthroplasty and hybrid techniques are still relatively novel procedures despite promising short-term and mid-term outcomes. Long-term studies demonstrating superiority over fusion are required before these techniques may be recommended to replace fusion as the gold standard. Novel stem cell approaches combined with tissue engineering therapies continue to be developed in expectation of improving clinical outcomes. Results with appropriate follow-up are not yet available to indicate if such techniques are safe, cost-effective and reliable in the long-term.

Reconstruction of Chronic Foveal TFCC Tears with an Autologous Tendon Graft.

Background A triangular fibrocartilage complex (TFCC) injury can produce distal radioulnar joint (DRUJ) instability. If the foveal attachment is avulsed, it translates distally. The footprint is separated from its origin and will become covered in synovitis, preventing healing. The authors describe a surgical technique for the treatment of instability of the DRUJ due to chronic foveal detachment of the TFCC. Technique The procedure utilizes a loop of autologous palmaris longus tendon graft passed through the ulnar aspect of the TFCC and through an osseous tunnel in the distal ulna to reconstruct the fovel attachment. Patients and Methods We report on nine patients with a mean age of 42. Median follow-up was 13 months. Results The median pain scores measured were reduced from 8 to 3 postoperatively, and all had a stable DRUJ. Conclusions This technique provides stability of the distal ulna to the radius and carpus, with potential for biologic healing through osseous integration. It is a robust, anatomically based reconstruction of the TFCC to the fovea that stabilizes the DRUJ and the ulnar-carpal sag.

Anatomic foveal reconstruction of the triangular fibrocartilage complex with a tendon graft.

An acute injury to the triangular fibrocartilage complex (TFCC) with avulsion of the foveal attachment can produce distal radioulnar joint (DRUJ) instability. The avulsed TFCC is translated distally so the footprint will be bathed in synovial fluid from the DRUJ and will become covered in synovitis. If the TFCC fails to heal to the footprint, then persistent instability can occur. The authors describe a surgical technique indicated for the treatment of persistent instability of the DRUJ due to foveal detachment of the TFCC. The procedure utilizes a loop of palmaris longus tendon graft passed through the ulnar aspect of the TFCC and into an osseous tunnel in the distal ulna to reconstruct the foveal attachment. This technique provides stability of the distal ulna to the radius and carpus. We recommend this procedure for chronic instability of the DRUJ due to TFCC avulsion, but recommend that suture repair remain the treatment of choice for acute instability. An arthroscopic assessment includes the trampoline test, hook test, and reverse hook test. DRUJ ballottement under arthroscopic vision details the direction of instability, the functional tear pattern, and unmasks concealed tears. If the reverse hook test demonstrates a functional instability between the TFCC and the radius, then a foveal reconstruction is contraindicated, and a reconstruction that stabilizes the radial and ulnar aspects of the TFCC is required. The foveal reconstruction technique has the advantage of providing a robust anatomically based reconstruction of the TFCC to the fovea, which stabilizes the DRUJ and the ulnocarpal sag.

Confirmation of microevolutionary increase in spina bifida occulta among Swiss birth cohorts.

Previous studies on the prevalence of spina bifida occulta have indicated a microevolutionary increase in its frequency and possible population differences in the prevalence of the condition. We studied the frequencies of closed and open sacral canals at each sacral level among two birth cohorts in Switzerland. Transverse CT scans and multiplanar reconstruction images of sacra of 95 males and 96 females born in 1940-1950 and 99 males and 94 females born in 1970-1980 in Switzerland were reviewed. We found that individuals born later have significantly more open sacral arches at all sacral levels compared to those born 30-40 years earlier. When results were related to previously published data on Australian cohorts, the trend was the same, but Swiss in both cohorts were less likely to have an open section than Australians at all locations apart from S2. This study confirmed a microevolutionary trend in the opening of sacral canal among two different generations in Switzerland and demonstrated a population difference in the prevalence of spina bifida occulta.

Secular trend in the opening of the sacral canal: an Australian study.

STUDY DESIGN: Computer tomography scans were used to asses the opening of the sacral canal. OBJECTIVE: We investigated the prevalence of sacral spina bifida occulta in 2 population groups: born 1940 to 1950 and 1980 to 1990. SUMMARY OF BACKGROUND DATA: Comparison of the prevalence of spina bifida occulta in the first-century Pompeii with that in 20th century European and Mediterranean populations indicates that the degree of the closure of vertebral arches in the sacrum has undergone changes and the prevalence of spina bifida occulta is increasing. METHODS: Transverse computer tomograph scans and multiplanar reconstruction images of sacra of 100 males and 100 females born 1940 to 1950 and 100 males and 100 females born 1980 to 1990 were used after ethics committee approval. RESULTS: The individuals born later have significantly more open sacral arches when compared with those born 40 years earlier, especially in the midsacral region. Also, males have open sacral arches in the rostral segments of the sacrum more than females. CONCLUSION: This study demonstrates a secular trend in the opening of the sacral canal in both sexes that occurred within 2 generations. Also, the increased prevalence of open sacral canal in males suggests a different response between sexes to the forces of evolution.