In a retrospective cohort study we compared the clinical outcome and complications, including dysphagia, following anterior cervical fusion for the treatment of cervical spondylosis using either a zero-profile (Zero-P; Synthes) implant or an anterior cervical plate and cage. A total of 83 patients underwent fusion using a Zero-P and 107 patients underwent fusion using a plate and cage. The mean follow-up was 18.6 months (. sd. 4.2) in the Zero-P group and 19.3 months (. sd. 4.1) in the plate and cage group. All patients in both groups had significant symptomatic and neurological improvement. There were no significant differences between the groups in the Neck Disability Index (NDI) and visual analogue scores at final follow-up. The cervical alignment improved in both groups. There was a higher incidence of dysphagia in the plate and cage group on the day after surgery and at two months post-operatively. All patients achieved fusion and no graft migration or nonunion was observed. When compared with the traditional anterior cervical plate and cage, the Zero-P implant is a safe and convenient procedure giving good results in patients with symptomatic cervical spondylosis with a reduced incidence of dysphagia post-operatively. Cite this article: Bone Joint J 2013;95-B:543–7

Aim: To determine the incidence of adjacent level osteophytes in patients who have had anterior cervical fusion using an anterior cervical plate as compared to those who are fused without an anterior cervical plate. Design: We retrospectively reviewed the lateral radiograms of sixty two patients who have had an anterior cervical fusion with a minimum follow up of twelve months. Materials and methods: We looked for the development of adjacent level osteophytes in these patients at their final follow up, which was generally at the time radiological fusion. There were 27 patients in the first group who had an anterior cervical plate used to fix the vertebrae in addition to the Cervios cage, while the 35 patients in the second group in whom only a Rabea cage was used for the fusion. The mean follow-up was 20.6 months (range 12–48). Results: 64.3% of the patients who had an anterior cervical plate developed adjacent level osteophytes while none of the patients who have had the fusion without the cage developed the osteophytes. Conclusion: We found the patients who had an anterior cervical interbody fusion using a plate had a significant risk of developing adjacent level osteophytes while this is not seen in patients who do not have the plate for the fixation

Introduction Anterior correction of cervical kyphotic deformity in traumatic and degenerative spine is a well established technique. The application of an anterior cervical plate is widely accepted, particularly in multilevel discectomies. However the placement of the cervical plate flush against the cortical margins of the spine remains challenging particularly when there is an underlying subluxation. Contouring the cervical plate with a plate bender is suggested. Others have described the use of an adjustable depth tap (. 1. ). We describe the technique of utilizing the Trimline™ Vertebral Body Distractor in correction of the sagittal plane deformity and maximizing the contact surface between plate and fusion construct. Methods The technique is described in a case each of cervical trauma and degenerative cervical spondylolisthesis. The Trimline™ distractor which utilizes cannulated legs, threaded pins and nuts is used as a direct reduction tool correcting the cervical lordosis, before discectomy. The distractor pins are placed bilaterally in the vertebral bodies at the level of the deformity, and at the level above and below. The distractors are applied bilaterally and reduction undertaken. The distraction device is locked in place whilst the discectomy is performed. Distraction device is removed once graft is in-situ and cervical plate is applied in routine manner. Results Bilateral application of pins and distraction device provides better reduction strength, and better distributes distraction forces minimizing further fracture. This optimizes correction of cervical kyphotic deformity and prevents obstruction of operative view for discectomy and fusion. Discussion Restoration of the normal cervical lordotic curve in traumatic and degenerative spinal disease remains challenging. Flush application of the anterior cervical plate to the anterior border of the spine and graft enhances spinal fusion, stability and alignment. The use of bilateral vertebral body distractor devices to reduce cervical subluxation and enhance implant-bone interface is a novel technique which is safe and not time consuming

Determine the detection rate of modern spinal implants using the current technology. There is a paucity of data regarding detection rates of modern spinal implants using modern walk-through pulsed archway metal detectors (AMDs). No published reports compare detection capability with hand-held metal detectors (HHMDs). ex-vivo & in-vivo comparison of detection rates using AMD & HHMD (set to maximum DoT sensitivities), in patients of varying Body Mass Index (BMI), implants, implant mass/density and alloys. 40 patients with: lumbar disc replacement (CoCr) (n=8), cervical disc replacement (CoCr) (1), posterior deformity instrumentation (17), anterior deformity instrumentation (2), anterior reconstruction (2), PLIF (6), interspinous distraction device (1), anterior cervical plate (2) ALIF (1), All implants were titanium unless indicated. Mean metal mass was 98g (range 6g-222g). The AMD did not detect any instrumentation individually or in combination up to a titanium mass totalling 215g. The HHMD detected all instrumentation at a distance of 5cm; with the minimum mass being 2g. No implants were detected in patients by the AMD. The HHMD did not detect any anterior lumbar or thoracic surgical implants. It detected anterior cervical implants. The HHMD detected all posterior surgical implants. There was no significant relationship between detection, BMI, total metal mass, and metal density/segment. AMD detectors do not detect modern spinal implants. HHMD detect all modern posterior spinal implants; this has implications for patient documentation

Introduction. Anterior reconstruction has the advantage of conferring immediate stability to the cervico-thoracic junction. Aims and objectives. Assess clinical and radiological outcome in cervico-thoracic kyphosis treated with anterior reconstruction. Material and methods. 62 cases were treated with anterior reconstruction from 1996-2007. Minimum follow-up was 2years (2-6). Indications included tuberculosis (45), dysplastic(10), neoplastic (3) and traumatic (4). Average age was 28.6 years (13-72 years). Average pre-operative kyphosis was 26.4 degrees (5-84). Patients were grouped as long-neck (35) and short-neck (27) according to classification proposed by Bapat and Laheri. The caudal normal vertebra (CNV) matched on plain radiology and MRI in 40 (64.51%). In 22 level of fixation was extended due to poor bone mass in the adjacent vertebral body (caudal 17, cranial 5). Pre-operative neurological deficit was seen in 57 (91.3%) and average Nurick's grade was 3.8 (0-5). Results. 32 long-neck patients required strap-muscle tenotomy to expose the CNV. In 3(9.3%) manubriotomy was required (large neck girth 1, thyroid goitre 2). 26 short-neck patients required manubriotomy for plate placement. In 42 (67.8%) patients a standard anterior cervical plate was used. In 22 locking plate was used. Commonest cranial and caudal vertebrae instrumented were C7 (32) and T2 (20) respectively. Post-operative kyphosis averaged 14.68 degrees (0-78) and correction averaged 11.72 degrees. Average post-operative Nurick's grade was 2.8. One patient with fracture dislocation of T1-T2 and traumatic oesophageal rupture died. In 1 the implant loosened and was revised with posterior construct. In 1, screw loosening was observed but implant position remained unaltered. 2 patients had recurrent laryngeal palsy. Iatrogenic pleural rent occurred in 2 patients. Transient dysphagia was noticed in 12. The scar hypertrophy was seen in 30(48.38%). The loss of correction averaged 2.3mm (0-4mm) at the final follow-up. Conclusion. Anterior reconstruction allows excellent reconstruction of cervico-thoracic junction obviating need for a posterior construct

Introduction Adjacent segment disease with radiculopathy and neurologic deficit adjacent to a non-mobile spinal segment is the ideal application for cervical arthroplasty. Not only are the stresses and loads increased but unfortunately the previously fused segment is further compromised by being fixed in a kyphotic position. Methods This is a prospective study of 40 PCM prostheses inserted in thirty patients with 50 adjacent segments previously fused or rendered immobile—ten cases were performed as bi-level implantations. The inclusion and exclusion criteria were otherwise identical to the normal FDA prospective IDE criteria with all patients presenting with radiculopathy and a corresponding neurologic deficit confirmed by an MRI compressive lesion. Results The mean preoperative cervical lordosis was 2.65 degrees (−32 to 25), mean postoperative lordosis 12.3 degrees (−17 to 30), and the mean improvement was 9.4 degrees of cervical lordosis (range (−15 to 23). EBL = 0 to 100 cc with no patients requiring blood transfusions, Length of surgery = mean 104 minutes (60 to 150) and the length of hospital stay = mean 1.17 days (0 to 3 days). The clinical follow-up was greater than 2 years. All patients were neurologically intact at follow up with a mean improvement of NDI = 50 % and mean improvement in VAS = 58.3 %.The range of flexion and extension motion at the level of the prosthesis was a mean of 8.9 degrees (range 4 to 20 degrees). Discussion Naturally, the adjacent segment application of a cervical disc replacement is a challenging clinical environment for cervical arthroplasty – by definition every case had prior surgery. Not only is the cervical spine position often compromised by being in excessive kyphosis, but seventeen of the 50 previously fused levels had prior cervical instrumentation. 5 patients had previous cervical cages, 2 had cage-plates, 5 patients had previous anterior cervical plates, one had a prior arthroplasty device with HO, and 4 patients had PMMA which required revision. Despite the complicated nature of the presenting pathology, the Porous Coated Motion Cervical prosthesis successfully restored some element of cervical lordosis, and restored stability to the cervical segments. An added potential bonus is the preserved 9.4 degrees of flexion – extension mobility. The PCM appeared to work well in these revision cases. This is the world’s largest study to date investigating prospectively the value of cervical arthroplasty in adjacent segment disease

Introduction Locking plates are the most used devices for achieving anterior cervical spinal fusion and offer considerable advantages such as faster and easier implantation and fewer implant-related failures than older plate systems. Recently polyaxial locking screws were introduced to make the implantation of these plates even easier by facilitating the implantation of the screw in all directions. However polyaxial screws may have the disadvantage of losing the angular stability with subsequent failure of the plate. The aim of this study was the radiological follow up of the patients with polyaxial screw and to compare them with the conventional looking plates. Methods Patients underwent anterior cervical discectomy and fusion in which either ventral cervical locking plates or a polyaxial locking screw were used for indications including cervical spondylotic radiculopathy, disc herniation, trauma, and myelopathy. Patients underwent anterior cervical discectomy and interbody fusion and / or corpectomy. Preoperative and postoperative radiographic data included sagittal angle, translation, and settling of the graft. Results One hundred and forty patients were investigated (mean age of 49 years) with an average follow up period of 21.5 months (range from 4 to 50 months). All underwent anterior cervical plate fusion as a component of the surgical treatment for symptomatic degenerative cervical spinal disease (55%) or for vertebral destruction caused by trauma (45%).100 (71%) of patients were treated with a conventional locking plate and 29 % with a plate with polyaxial screw fixation. Besides plate fixation, 4 of the 140 patients had a combined ventrodorsal fusion. In 46 cases (25%), one or more vertebral bodies were removed and replaced with either iliac bone graft (two levels, 21% of all cases) or fibula strutgraft (4%). In the group with conventional locking plates no patient had to be revised, 3 showed a subluxation (up to 1/3 of the vertebral body diameter) and 2 screw back out posteriorly without clinical relevance. In the group with the plate with polyaxial screw fixation two patient had to be revised (posterior stabilisation) because of subluxation due to loss of angular stability of the screws and one patient developed subluxation of 1/3 of the vertebral body also due to loss of angular stability. Discussion The complication rate and the revision rate for anterior cervical discectomy and fusion with plates with and without polyaxial screw fixation were similarly low. Polyaxial screw may have the theoretical disadvantage of loosening with loss of the angular stability and subsequent failure necessitating revision

Introduction: Anterior cervical discectomy and inter-body fusion (ACDF) is recognised as an effective surgical treatment for cervical degenerative disc disease. The goals of anterior discectomy, interbody graft placement, and subsequent fusion, are to improve and maintain intervertebral height, establish and maintain physiological cervical lordosis, and achieve arthrodesis so as to eliminate pathological motion. Establishing the most clinically effective and cost effective operative approach to achieve these goals while, at the same time, minimising post-operative complications, is currently an evolving process. One view is that the use of anterior cervical plates reduces graft-related complications, maintains the cervical alignment, and leads to a higher incidence of fusion. In addition, there is evidence to suggest that there is a direct cost benefit of earlier return to pre-operative function and employment. Bone graft: Iliac crest autograft would be regarded as the gold standard source of bone for ACDF. However, donor site complications (due to harvesting autograft) are not insignificant and range from 1% to a sizeable 29%. These complications include iliac crest fracture, infection, persisting pain, neural injury, bowel injury, etc. With the advent of bone banks, allograft has become available and eliminates the problem of graft-harvest related complications. There is a theoretical risk of disease transmission and a corresponding difficulty with patients accepting donated tissue. To date, no HIV cases transmission has occurred from ACDF allograft. There are several studies that demonstrate a significant difference in fusion rates when comparing allograft and autograft. The preponderance of data from the literature supports the conclusion that the use of allograft in ACDF can lead to a higher incidence of graft collapse, pseudarthrosis, and possible subsequent revision surgery. Bishop et al., (Spine 1991 16:726–9): have documented a higher increase in pseudarthrosis rate, graft collapse, and interspace angulation in the allograft group compared to the autograft group. Therefore, the dilemma of allograft being preferred as a basis of eliminating graft harvesting complications, while at the same time being associated with a higher incidence of fusion failure and deformity, have led some surgeons to trial the combination of allograft with anterior plate fixation. Shapiro (J Neurosurg 1966 84:161–5) has reported no incidences of fusion failure, graft collapse, progressive kyphosis, or plate-related complications in 82 consecutive single and multiple level ACDF’s using allograft and anterior plating. Treatment failure: The incidence of the following complications have been reported in the literature. (Graham JJ. Spine 1989 14:1046–50). Pseudarthrosis – 3%–36%. Graft collapse – 3%–14%. Graft extrusion – 0.5%–4%. These figures are regardless of the graft source and are significant. Recent studies show that the combination of graft and anterior plate fixation virtually eliminates the complication of graft extrusion, and also decreases the risk of graft collapse and development of pseudarthrosis. There are also studies that contend that plate fixation can maintain proper lordotic alignment of the spine more effectively than can ACDF without plating. I contend that the use of contemporary cervical plates significantly decreases the rate of fusion failure and graft-related complications without imparting significant implant-related complications. As a result, there is decreased overall risk to the patient. The current type of plates which are available are unicortical with locking systems that substantially decrease the risk of screw loosening or hardware migration

RhBMP2 was used in thirty-six consecutive patients requiring interbody fusion with fifty-five levels (thirteen patients twenty levels ALIF, twelve patients seventeen levels TLIF, eleven patients eighteen levels ACDF) using anterior cervical locking plates and lumbar posterior pedicle screw constructs. All patients showed radiographic fusion at six months. Early lucency, subsidence, and increased pain occurred between six weeks and three months in 70% of ALIFS, 53% of TLIFS and 33% of ACDF’s. The average subsidence was 27% in ALIFS, 24% in TLIFS, and 53% in ACDF. Pain improved by the sixth month. We recommend alternative structural support when using RhBMP2. To determine effectiveness of RhBMP2 in interbody fusion with machined allograft spacers (MTF Synthes Spine USA femoral ring, TLIF and fibular ring cervical spacers). A prospective study of thirty-six consecutive patients requiring interbody fusion with fifty-five levels (thirteen patients twenty levels ALIF, twelve patients seventeen levels TLIF, eleven patients eighteen levels ACDF). Machined allograft spacers and RhBmp2 were supplemented with anterior locking plates in the cervical spine while the lumbar segments were supplemented posterior pedicle screws constructs. Patients were followed at two weeks, six weeks, three months, six months, one year. Patients were examined, had xrays, completed Oswestry scores, pain diagrams, and VAS for pain preoperatively and at every follow up appointment. All the patients showed radiographic evidence of fusion at six months after surgery. Early lucency and subsidence of allografts was observed in 70% of ALIFS, 53% of TLIFS and 33% of ACDF’s. The average subsidence was 27% (range13–42%) in ALIFS, 24% in TLIFS (range 13–40%), and 53% in ACDF. Subsidence and reporting of increased pain occurred between the six- week and three month follow up after which patients improved. Although high rates of early fusion can be accomplished with allograft spacers and rhBMP2 significant subsidence occurs in greater than 50% of lumbar cases and 30% of cervical cases due to early turnover and loss of structural support of the allograft. We recommend alternative structural support when using RhBMP2

We investigated the static and cyclical strength of parallel and angulated locking plate screws using rigid polyurethane foam (0.32 g/cm³) and bovine cancellous bone blocks. Custom-made stainless steel plates with two conically threaded screw holes with different angulations (parallel, 10° and 20° divergent) and 5 mm self-tapping locking screws underwent pull-out and cyclical pull and bending tests. The bovine cancellous blocks were only subjected to static pull-out testing. We also performed finite element analysis for the static pull-out test of the parallel and 20° configurations. In both the foam model and the bovine cancellous bone we found the significantly highest pull-out force for the parallel constructs. In the finite element analysis there was a 47% more damage in the 20° divergent constructs than in the parallel configuration. Under cyclical loading, the mean number of cycles to failure was significantly higher for the parallel group, followed by the 10° and 20° divergent configurations.

In our laboratory setting we clearly showed the biomechanical disadvantage of a diverging locking screw angle under static and cyclical loading.

We evaluated the efficacy of anterior fusion alone compared with combined anterior and posterior fusion for the treatment of degenerative cervical kyphosis. Anterior fusion alone was undertaken in 15 patients (group A) and combined anterior and posterior fusion was carried out in a further 15 (group B). The degree and maintenance of the angle of correction, the incidence of graft subsidence, degeneration at adjacent levels and the rate of fusion were assessed radiologically and clinically and the rate of complications recorded. The mean angle of correction in group B was significantly higher than in group A (p = 0.0009). The mean visual analogue scale and the neck disability index in group B was better than in group A (p = 0.043, 0.0006). The mean operation time and the blood loss in B were greater than in group A (p < 0.0001, 0.037). Pseudarthrosis, subsidence of the cage, and problems related to the hardware were more prevalent in group A than in group B (p = 0.034, 0.025, 0.013).

Although the combined procedure resulted in a longer operating time and greater blood loss than with anterior fusion alone, our results suggest that for the treatment of degenerative cervical kyphosis the combined approach leads to better maintenance of sagittal alignment, a higher rate of fusion, a lower incidence of complications and a better clinical outcome.