Anterior Vertebral Fusion Research Articles

Use of a nano-hydroxyapatite/polyamide composite in anterior cervical subtotal corpectomy and fusion

This study aimed to explore the safety and efficacy of using nano-hydroxyapatite/polyamide (N-HA/PA) composite in anterior cervical vertebral body subtotal corpectomy and interbody fusion. Total 50 patients with cervical spondylotic myelopathy were enrolled to undergo anterior cervical spondylectomy. Bone graft pedicles were compounded with N-HA/PA and intervertebral body fusion was performed. Study outcomes included surgical efficacy and the degree of fusion. Patients in whom vertebral body fusion was performed with N-HA/PA composite pedicles had significantly improved symptoms. The postoperative Japanese Orthopaedic Association scores increased to 18.56±4.37 from 11.37±3.52, reflecting an improvement rate of 87.3%. The composite pedicle fusion rate was 96.4%. Therefore, N-HA/PA composite pedicle as a bone graft material in fusion surgery provides significant therapeutic efficacy. Moreover, the composite pedicle fusion rate is high, making it ideal for anterior cervical vertebral body subtotal corpectomy and fusion.

Cost-Utility Analysis of Anterior Vertebral Body Tethering versus Spinal Fusion in Idiopathic Scoliosis from a US Integrated Healthcare Delivery System Perspective

PurposeAnterior vertebral body tethering (VBT) is a non-fusion, minimally invasive, growth-modulating procedure with some early positive clinical outcomes reported in pediatric patients with idiopathic scoliosis (IS). VBT offers potential health-related quality of life (HRQoL) benefits over spinal fusion in allowing patients to retain a greater range of motion after surgery. We conducted an early cost-utility analysis (CUA) to compare VBT with fusion as a first-choice surgical treatment for skeletally immature patients (age >10 years) with moderate to severe IS, who have failed nonoperative management, from a US integrated healthcare delivery system perspective.Patients and MethodsThe CUA uses a Markov state transition model, capturing a 15-year period following index surgery. Transition probabilities, including revision risk and subsequent fusion, were based on published surgical outcomes and an ongoing VBT observational study (NCT02897453). Patients were assigned utilities derived from published patient-reported outcomes (PROs; SRS-22r mapped to EQ-5D) following fusion and the above VBT study. Index and revision procedure costs were included. Probabilistic (PSA) and deterministic sensitivity analyses (DSA) were performed.ResultsVBT was associated with higher costs but also higher quality-adjusted life years (QALYs) than fusion (incremental costs: $45,546; QALYs gained: 0.54). The subsequent incremental cost-effectiveness ratio for VBT vs fusion was $84,391/QALY gained. Mean PSA results were similar to the base case, indicating that results were generally robust to uncertainty. The DSA indicated that results were most sensitive to variations in utility values.ConclusionThis is the first CUA comparing VBT with fusion in pediatric patients with IS and suggests that VBT may be a cost-effective alternative to fusion in the US, given recommended willingness-to-pay thresholds ($100,000–$150,000). The results rely on HRQoL benefits for VBT compared with fusion. For improved model accuracy, further analyses with longer-term PROs for VBT, and comparative effectiveness studies, would be needed.

Progressive Non-infectious Anterior Vertebral Fusion (Copenhagen Syndrome); A Case Report and Literature Review

Progressive anterior vertebral fusion (PAVF or Copenhagen syndrome) is a very rare cause of pathologic kyphosis that gradually and progressively leads to anterior vertebral fusion. In this report, we described a 13-year-old girl with PAVF presented to the orthopedic clinic of Imam Reza Hospital with rigid thoracic kyphosis (900) in 2019. She underwent two stages anterior and posterior spinal surgery and was finally discharged with a normally aligned spine and good general condition. In pediatric patients presented with thoracic or thoracolumbar kyphosis, in addition to the common diseases that cause kyphosis, PAVF should also be considered.

Damage to the human lumbar cartilage endplate and its clinical implications.

The cartilaginous endplate (CEP) is a thin layer of hyaline cartilage, and plays an important role in the diffusion of nutrients into the intervertebral discs. Its damage may seriously affect the disc degeneration, and result in low back pain (LBP). However, the structural features of damaged CEPs have not been well characterized, and this hinders our understanding of the etiology of disc degeneration and pain. To present the structural features of micro-damaged CEPs in patients with disc degeneration and LBP that might even be regarded as an initial factor for disc degeneration, we performed a histological study of micro-damaged CEPs harvested from human lumbar intervertebral discs and analyzed its clinical implications. Human lumbar CEPs were excised from 35 patients (mean age 60.91years) who had disc degeneration and LBP. Control tissue was obtained from 15 patients (mean age 54.67years) with lumbar vertebral burst fractures. LBP and disability were assessed clinically, and all patients underwent anterior vertebral body fusion surgery. CEPs together with some adjacent nucleus pulposus (NP) were sectioned at 4µm, and stained using H&E, Safranin O/Fast Green, and Alcian Blue. Immunostaining and PCR were used to identify various markers of degeneration, innervation, and inflammation. Histology demonstrated physical micro-damage in 14/35 CEPs from the disc degeneration group. Six major types of damage could be distinguished: fissure, traumatic nodes, vascular mimicry, incorporation of NP tissue within the CEP, incorporation of bone within the CEP, and incorporation of NP and bone within the CEP. Pain and disability scores (ODI: p=0.0190; JOA: p=0.0205; JOABPEQ: p=0.0034) were significantly higher in those with micro-damaged CEPs (N=14) than in those with non-damaged CEPs (N=21). CEP damage was significantly associated with elevated MMP3 (p=0.043), MMP13 (p=0.0191), ADAMTS5 (p=0.0253), TNF-α (p=0.0011), and Substance P (p=0.0028), and with reduced Sox9 (p=0.0212), aggrecan (p=0.0127), and type II collagen (p=0.0139). In conclusion, we presented a new classification of human lumbar micro-damaged CEPs. Furthermore, we verify disc degeneration, innervation, and discogenic pain in micro-damaged CEPs.

Evaluation of Anterior Vertebral Interbody Fusion Using Osteogenic Mesenchymal Stem Cells Transplanted in Collagen Sponge

The study used a rabbit model to achieve anterior vertebral interbody fusion using osteogenic mesenchymal stem cells (OMSCs) transplanted in collagen sponge. We investigated the effectiveness of graft material for anterior vertebral interbody fusion using a rabbit model by examining the OMSCs transplanted in collagen sponge. Anterior vertebral interbody fusion is commonly performed. Although autogenous bone graft remains the gold-standard fusion material, it requires a separate surgical procedure and is associated with significant short-term and long-term morbidity. Recently, mesenchymal stem cells from bone marrow have been studied in various fields, including posterolateral spinal fusion. Thus, we hypothesized that cultured OMSCs transplanted in porous collagen sponge could be used successfully even in anterior vertebral interbody fusion. Forty mature male White Zealand rabbits (weight, 3.5-4.5 kg) were randomly allocated to receive one of the following graft materials: porous collagen sponge plus cultured OMSCs (group I); porous collagen sponge alone (group II); autogenous bone graft (group III); and nothing (group IV). All animals underwent anterior vertebral interbody fusion at the L4/L5 level. The lumbar spine was harvested en bloc, and the new bone formation and spinal fusion was evaluated using radiographic analysis, microcomputed tomography, manual palpation test, and histologic examination at 8 and 12 weeks after surgery. New bone formation and bony fusion was evident as early as 8 weeks in groups I and III. And there was no statistically significant difference between 8 and 12 weeks. At both time points, by microcomputed tomography and histologic analysis, new bone formation was observed in both groups I and III, fibrous tissue was observed and there was no new bone in both groups II and IV; by manual palpation test, bony fusion was observed in 40% (4/10) of rabbits in group I, 70% (7/10) of rabbits in group III, and 0% (0/10) of rabbits in both groups II and IV. These findings suggest that mesenchymal stem cells that have been cultured with osteogenic differentiation medium and loaded with collagen sponge could induce bone formation and anterior vertebral interbody fusion. And the rabbit model we developed will be useful in evaluating the effects of graft materials for anterior vertebral interbody fusion. Further study is needed to determine the most appropriate carrier for OMSCs and the feasibility in the clinical setting.

Progressive non-infectious anterior vertebral fusion in a baby with Saethre-Chotzen-acrocephalosyndactyly type III syndrome

We report on a 3-months old baby of Austrian origin and product of non-consanguineous parents. Abnormal craniofacial contour was the main deformity. The overall clinico-radiographic features were consistent with Saether-Chotzen-acrocephalosyndactyly type III syndrome. Bi-directional sequencing of the exon 8 and of the FGFR3-genes, exons 7 of FGFR3 (Fibroblast growth factor receptor3) genes, the exon 5 of the FGFR1 gene, revealed no mutations. Sagittal MRI imaging of the spine showed anterior vertebral fusion along the thoraco-lumbar vertebrae compatible with the non-infectious type.

50 Years Ago in CORR: Anterior Excision and Vertebral Body Fusion for Intervertebral Disk Syndromes of the Lower Lumbar Spine: Three- to Five-Year Results in 224 Cases Paul H. Harmon, MD, FACS CORR 1963;26:107-127

Most contemporary reports of the results of surgical procedures routinely describe complications. (A symposium in this issue—Volume 470 Issue No. 6 of CORR—is devoted to complications of spinal surgery.) Harmon, in 1960 [1] and 1963 [2], described in detail an anterior surgical approach for treating disc protrusion and degenerated discs, “utilizing a surgical approach that is free of the hazard of blood loss and where vision of the pathology is optimal” [1]. Complications were not always emphasized in reports from the literature of that time. In these two articles, Harmon mentions medical complications only several times, despite reporting large numbers of cases (250 in the 1960 article and 650 in the 1963 article): “…there has been only a single case (from a total of 550 cases) with neurologic complications…” and “The mortality has been nil, neurologic complications negligible, and the morbidity from all causes has been less than 1 per cent” [2]. He considered pseudarthrosis a “severe complication.” Harmon emphasized surgical techniques in both articles (the earlier article [1] contains two-parts, with the second devoted to technique). Figures 10 and ​and1111 from his 1963 article illustrate the types of grafts he considered essential to achieve fusion. “Definite trabecular osseous union has been observed in 95 per cent with autogenous grafts. A rate of union 10 per cent lower has been observed with frozen homogenous grafts.” He favored autogenous “sandwich grafts” consisting of alternate layers of tibial cortical and cancellous bone. Fig. 10 Halftone drawings, demonstrating a transvertebral grafting procedure on the anterior aspect of the lumbosacral joint. The lower right-hand figure shows insertion of full -thickness iliac graft, “coin” type. Two such grafts per level are ... Fig. 11 An alternative technique of preparation of graft bed and insertion of 2 rectangular grafts illustrated for the L-4 level: (A) incision in the anterior ligament; (B) preparation of graft bed; (C) completed grafting procedure. (Reprinted with permission ... Harmon used a characteristic categorical rating of the times: “Good and excellent results are both highly acceptable; in the former arc persons exhibiting only occasional and fleeting nonincapacitating reminders of their former disorder, while in the latter, the patients are entirely without symptoms. Fair results describe patients who are occasionally disabled with recurrent low back pains and/or radicular pain, but are improved as compared with their preoperative state. Unimproved (or poor) is self-explanatory.” In various subcategories, he reported 80% to 96% good or excellent results. “Considering all diagnostic subdivisions and all age groups, good and excellent results have been obtained in slightly more than 90 per cent of the cases.” Such categories are rarely used in contemporary reporting because they are subjective, various surgeons would rate patients differently, and because we emphasize validated patient-generated evaluations. Today, most reports give complications more attention, perhaps owing to the emphasis on patient safety. Harmon’s reports were characteristic for the time, but we wonder how rigorously complications, including the less severe complications, were recorded: certainly they were not always reported. Nonetheless, he seemed to improve most of his patients using meticulous techniques.

Progressive anterior vertebral fusion: A report of three cases

We report a series of three cases of progressive anterior vertebral fusion diagnosed and monitored in our establishment. This very rare condition was discovered in young children while exploring a spinal deformity. With X-rays of the thoracolumbar spine it was possible to make a positive diagnosis and ensure follow-up. The radiographic semeiotics are characteristic and combine anterior pinching of the disc, well-delimited erosion of the anterior vertebral corners and anterior then posterior intervertebral ankylosis. MRI is very useful for assessing the extent of the intervertebral ankylosis and the condition of the residual discs, without irradiation. The condition develops over several months or years. Conservative treatment is usually sufficient.

Progressive noninfectious anterior vertebral fusion

A 9-year-old girl with back pain showed progressive spinal mobility restriction since age one, without a history of spondylodiscitis or neurological deficits. Laboratory tests were normal. Radiographs revealed lumbar lordosis rectification, anterior fusion between end plates from L2–L3 to L4–L5 levels, with prominent bone bridge in the latter, and anterior intervertebral narrowing at T11–T12 and L1–L2 (Fig. 1). MRI showed slight hypersignal on T1and T2-W images in the anterior portion of the multiple end plates (Fig. 1). There were no other spinal or clinical abnormalities. The clinicoradiological diagnosis was progressive, noninfectious anterior vertebral fusion, a rare disorder of early childhood with unknown etiology. It can be asymptomatic or associated with moderate pain, rigidity, thoracolumbar kyphosis and, rarely, neurological impairment [1]. Radiologically, it may start with anterior defects in the end plates, associated with local intervertebral narrowing accompanied by erosion and irregularity of the corresponding end plates and then fusion, which typically spares the posterior disc space, except in the late stages [1, 2]. Treatment generally consists of spinal bracing [2].

Neck Injury-Wrestling

Table of Contents Neck Injury - Wrestling HISTORY: 15-year-old wrestler was thrown down on the mat, landing on his head with his neck in hyperflexion. No LOC. He had severe posterior neck pain, could not move his extremities and had no sensation below his nipple line. Imaging studies revealed fracture/dislocation of C5/C6 with spinal cord compression. He was started on the spinal cord injury steroid protocol and underwent surgical C5-C6 reduction with anterior and posterior vertebral fusion. Postoperatively, he regained lower extremity movement and continued to have neurological recovery throughout his acute care course. He was transferred to a rehabilitation hospital one week after the injury. PHYSICAL EXAMINATION: Mental status intact. Aspen cervical collar in place. Motor exam: B/L Elbow flexors 5/5; Wrist extensors L 5/5, R 4/5; B/L Elbow extensors 5/5; Finger flexors L 2/5, R 0/5; Finger abductors L 1/5, R 0/5; Hip flexors L 5/5, R 4/5; B/L Knee extensors 5/5; B/L Ankle dorsiflexors 4/5; Ankle plantarflexors L 5/5, R 4/5. Voluntary anal contraction intact. Sensation: light touch impaired L3-S2 B/L. Pinpoint intact on R, impaired T4-S2 on L. Anal sensation intact. Reflexes absent in UEs and LEs. Bulbocavernosus reflex present. DIFFERENTIAL DIAGNOSIS: Incomplete spinal cord injury syndrome Complete spinal cord injury TESTS AND RESULTS: Postoperative cervical spine anterior-posterior and lateral radiographs: - Anterior and posterior spinal fusion of C5/C6, no malalignment Cervical spine CT: - Linear lucencies superior and inferior to the C5-C6 interbody fusion graft. FINAL/WORKING DIAGNOSIS: Central Cord Syndrome, C6 American Spinal Injury Association (ASIA) D Tetraplegia TREATMENT AND OUTCOMES: Medical management: DVT prophylaxis, skin protection, pain control, treatment of neurogenic bowel and bladder. Daily physical therapy. Independence with ambulation greater than 1,000 feet; able to negotiate stairs; independent transfers. Daily occupational therapy. Independence with activities of daily living. Discharged home after one-month rehabilitation course. Neck brace discontinued. Outpatient PT/OT. Advanced to ASIA Impairment Scale Level E. Returned to school the following academic year. Wishes to return to wrestling against medical advice.

Progressive noninfectious anterior vertebral fusion in a girl with axial mesodermal dysplasia spectrum

We report a 7-year-old-girl who presented with the clinical criteria of the axial mesodermal dysplasia spectrum. Her parents were first cousins. Her facial dysmorphism was compatible with Goldenhar syndrome and in addition, she had anterior noninfectious vertebral fusions of the cervical and the thoracolumbar vertebrae, a congenital dermal sinus and a hypoplastic sacrum. The urogenital and the anal-recto regions were normal. To the best of our knowledge, this is the first clinical report of a child with axial mesodermal dysplasia in association with progressive noninfectious anterior vertebral fusion.

Progressive vertebral fusion in a girl with spinal enchondromatosis

We report on a 9-year-old girl who presented with progressive restriction of spine mobility. Standard spinal radiographs revealed enchondromatous lesions spread out along the anterior end plates of the lumbar vertebrae and MR imaging showed progressive anterior vertebral fusion. The long bones, short tubular bones and flat bones were free of enchondromata, but arcs of chondroid calcifications were observed in the proximal femoral metaphyses. The clinical and the radiographic features encountered in our patient did not fit into any previously reported children with enchondromatosis.

Difficult Endotracheal Intubation Due to Membranous Tracheal Protrusion Induced by Osteophytes Growing after Anterior Vertebral Spinal Fusion Surgery

頸椎前方固定術後18年経過した50歳代後半の女性で骨棘形成による気管膜様部突出が原因と思われる挿管困難症例を経験した. 急速導入後, 気管挿管を試みたが, 喉頭展開は容易で声門は直視できるものの, 気管チューブが声門下を通過せず, 手術延期となった. 後日, 前回よりも細い気管チューブを使用し挿管を試みたが, 前回と同様に抵抗を感じた. 気管チューブを180°回転させたところ, 抵抗が消失し気管挿管できた. 後日, 頸椎X線側面像において頸椎の変形と気管膜様部突出が認められ, 従来の気管チューブでは挿管困難が予想される所見を得た. 頸椎前方固定術後の晩期合併症として, 頸椎変形による喉頭・気管の変形に注意する必要があると考えられた.

Progressive non-infectious anterior vertebral fusion, split cord malformation and situs inversus visceralis

BackgroundProgressive non-infectious anterior vertebral fusion is a unique spinal disorder with distinctive radiological features. Early radiographic findings consist of narrowing of the anterior aspect of the intervertebral disk with adjacent end plate erosions. There is a specific pattern of progression. The management needs a multi-disciplinary approach with major input from the orthopaedic surgeon.Case reportWe report a 12-year-old-female with progressive anterior vertebral fusion. This occurred at three vertebral levels. In the cervical spine there was progressive fusion of the lateral masses of the Axis with C3. Secondly, at the cervico-thoracic level, a severe, progressive, anterior thoracic vertebral fusion (C7-T5) and (T6-T7) resulted in the development of a thick anterior bony ridge and massive sclerosis and thirdly; progressive anterior fusion at L5-S1. Whereas at the level of the upper lumbar spines (L1) a split cord malformation was encountered. Situs inversus visceralis was an additional malformation. The role of the CT scan in detecting the details of the vertebral malformations was important. To our knowledge, neither this malformation complex and nor the role of the CT scan in evaluating these patients, have previously been described.ConclusionThe constellations of the skeletal abnormalities in our patient do not resemble any previously reported conditions with progressive anterior vertebral fusion. We also emphasise the important role of computerized tomography in the investigation of these patients in order to improve our understanding of the underlying pathology, and to comprehend the various stages of the progressive fusion process. 3D-CT scan was performed to improve assessment of the spinal changes and to further evaluate the catastrophic complications if fracture of the ankylosed vertebrae does occur. We believe that prompt management cannot be accomplished, unless the nature of these bony malformations is clarified.

Progressive non-infectious anterior vertebral fusion (Copenhagen Syndrome) in three children: features on radiographs and MR imaging

Progressive non-infectious anterior vertebral fusion is a rare childhood disease of unknown aetiology. It commonly presents with kyphosis associated with progressive fusion in the thoracolumbar spine. MR imaging features have not previously been described to our knowledge. Three cases presenting to our institution are described. All three children had other congenital or developmental problems. Plain radiographs showed typical features with narrowing and irregularity of the anterior endplates and developing anterior vertebral fusion. MR imaging was available in all (in one case sequentially at ages 1 and 12 years), and features demonstrated were anterior disc narrowing and anterior endplate irregularity progressing to fusion. Associated bone oedema or fatty replacement was seen in the endplates, and was most marked at the anterior corners.

Intraoperative Monitoring of Spinal Cord Function Using Motor Evoked Potentials via Transcutaneous Epidural Electrode During Anterior Cervical Spinal Surgery

Because false-positive results are not infrequent when monitoring somatosensory evoked potentials during surgery, monitoring of motor evoked potentials (MEPs) has been proposed and successfully used during the removal of spinal cord tumors. However, this often requires direct visual placement of an epidural electrode after a laminectomy. We evaluated the use of MEPs, recorded via a transcutaneously placed epidural electrode, to monitor motor pathway functional integrity during surgery on the anterior cervical spine. Sixteen patients underwent anterior cervical vertebral decompression and fusion for cervical myelopathy and/or radiculopathy. Before surgery, an epidural monitoring electrode was placed transcutaneously at the midthoracic level and was used to record MEPs after transcranial cortical electrical stimulation. Electrode placement was successful in all patients but one, and satisfactory baseline spinal MEPs were obtained except for one patient who had cerebral palsy with significant motor dysfunction. Patients showed no significant changes in spinal MEPs during surgery, and all had baseline or better motor function postoperatively. None had complications from epidural electrode placement or electrical stimulation. We conclude that motor pathways can be monitored safely during anterior cervical spinal surgery using spinal MEPs recorded via a transcutaneously placed epidural electrode, that MEP preservation during surgery correlates with good postoperative motor function, and that cerebral palsy patients may possess too few functional motor fibers to allow MEP recording.

Bovine dowels for anterior cervical fusion: experience in 66 patients with a note on postoperative CT and MRI appearance.

Anterior cervical discectomy and vertebral interbody fusion is a widely used technique in the treatment of radicular or cord compression. Instead of using autologous bone removed from the iliac crest, a heterologous bovine dowel was used for fusion. Sixty-six patients presenting with radicular pain or myelopathy were entered into the study retrospectively. Medial herniated, soft or calcified disc, osteophytes with and without herniated disc material, and bony stenosis at one or two levels were shown by CT or MRI studies. Postoperatively, 88% of the patients noted relief of pain and motor improvement. Most of the patients' sensory deficits and myelopathy improved within 6-12 months. No complications occurred and only one re-operation had to be performed at the same level. In the follow-up period between 1-4 years, no cases of instability after surgery were reported. Operating time and postoperative pain were reduced because bone harvest from the iliac crest was not necessary. In postoperatively performed CT and MRI, the bovine dowel was surrounded by a "halo"-like structure and the specific structure of the bovine implant was still present. No real bony fusion occurred, but clinical stability was equivalent to autologous bone fusion reported in the literature. However, there was no MRI evidence of "living bone tissue" within the bovine dowel. This finding is in contrast to the current belief that the bovine implant is replaced or infiltrated by bony growth.

Complications after transpedicular stabilization of the spine. A survivorship analysis of 163 cases.

The authors studied complications of transpedicular stabilization methods. One hundred and sixty-three consecutive transpedicular stabilization procedures were performed between January 1987 and December 1991. The indications for stabilization were trauma (33 cases), metastatic spinal disorder (30 cases), spinal stenosis (33 cases), spondylolisthesis (27 cases), ankylosing spondylitis (6 cases), low back pain (22 cases), and miscellaneous (12 cases). Patients records and the entire series of radiographs for each case were scrutinized by independent observers. All per- and postoperative complications, including implant loosening and fatigue, were recorded. Clinical and radiographic survivorship analyses of the implants were performed. Early complications were unusual and none were associated with permanent morbidity. The probability of not having the implant removed in the first postoperative year was 85%. There was a 40% risk of radiographic failure, defined as loosening or implant fatigue, at 6 months. The outcome was more favorable in cases in which anterior vertebral interbody fusion was also performed. Transpedicular fixation is a safe procedure with a low incidence of serious per- and early postoperative complications. The mechanical durability of transpedicular fixators used alone is a cause for concern.

The Fate of Anterior Vertebral Bone Grafts in Patients Irradiated for Neoplasm

Perioperative irradiation is often used with anterior decompression and vertebral interbody fusion for the treatment of spinal neoplasms, yet little is known regarding the healing potential of these grafts. This review of 25 patients with neoplasm who had anterior vertebrectomy, bone strut insertion, and perioperative irradiation was performed to look specifically for evidence of radiographic fusion as determined by plain radiographs, tomograms, or computed tomography reconstruction. Four of 25 patients (16%) were judged to have a pseudarthrosis. All four pseudarthrosis patients but only four of 21 fusion patients had 4000 cg or more of irradiation, a statistically significant difference. There was a trend for lumbar lesions to have a higher risk for nonunion. Concomitant posterior stabilization did not necessarily prevent pseudarthrosis. Two iliac strut grafts with a pseudoarthrosis developed late fracture and one went on to collapse into kyphosis. The pseudarthrosis rate of anterior vertebral strut grafts in the face of irradiation for tumor is relatively high, and late graft fracture can occur if pseudarthrosis develops. Probable risk factors include irradiation greater than 4000 cg and lumbar lesions. Posterior stabilization to protect the graft may be warranted in the highest-risk patients.

Klippel-Feil syndrome: patterns of bony fusion and wasp-waist sign

Cervical spine radiographs of 33 patients with Klippel-Feil syndrome were studied for patterns of bony fusion and presence of wasp-waist sign. Five patients were found to have the classic features of massive cervical fusion. Two patients with two adjacent levels of bony fusion showed a wasp-waist sign. Fusion at one level of the cervical spine accounted for 26 remaining cases. The wasp-waist sign was observed in 14 of the cases in which there was complete vertebral interbody fusion, making this finding a valuable radiologic sign. Partial anterior or posterior vertebral interbody fusion, or isolated fusion of the neural arch, however, may or may not be associated with the wasp-waist sign. Klippel-Feil syndrome, easy to recognize when presenting with classic features or when associated with the wasp-waist sign, may be confused with a variety of other entities.