Anterior Corpectomy Research Articles

Unstable burst fractures of the thoraco-lumbar junction: treatment by posterior bisegmental correction/fixation and staged anterior corpectomy and titanium cage implantation

Controversy exists about the best treatment of unstable thoraco-lumbar (TL) burst fractures. Kyphosis correction and canal decompression in case of a neurological deficit are recognized treatment objectives, and various conservative and surgical strategies have been proposed. This prospective observational study evaluates the benefits and risks of a posterior bisegmental transpedicular correction/fixation and staged anterior corpectomy and titanium cage implantation in unstable TL junction burst fractures. 20 consecutive patients with a single-level traumatic unstable burst fracture at the TL junction were operated on by a bisegmental posterior correction/fixation, followed by anterior corpectomy and titanium cage implantation 7-10 days later. The radiological and clinical course is documented over a period of 24 months. The mean posttraumatic loss of anterior vertebral body height was 58% (45-70%). The posttraumatic mean regional kyphosis was 16 degrees and could be corrected by the posterior approach to a mean lordosis of 2 degrees. Mean secondary loss of the kyphosis correction was 3 degrees over 24 months. No hardware failure occurred, and construct stability was observed in all 20 patients. One surgical complication occurred during the posterior approach, and three transient surgical complications by the anterior approach. 12 of the 14 patients with an initial neurological deficit recovered an average of 1.5 grades on the ASIA scale. At 24 months postoperatively, the mean regional TL back pain on a VAS (0-10) was 1.6, and the mean pain at the anterior approach site was 1.2. Posterior bisegmental transpedicular correction/fixation and staged anterior corpectomy and titanium cage implantation is a safe and reliable surgical treatment option in unstable TL junction burst fractures. The advantages of this technique are a complete kyphosis correction, immediate stability, maintenance of kyphosis correction, and complete spinal canal decompression in case of a neurological deficit. However, these advantages have to be carefully weighed against the double approach morbidity.

Radiculopathy of C-5 after anterior decompression for cervical myelopathy

The authors conducted a study to examine the incidence and causes of postoperative C-5 radiculopathy, and they suggest preventive methods for C-5 palsy after anterior corpectomy and fusion. The authors included in the study 18 patients with postoperative C-5 radiculopathy from 563 patients who underwent anterior decompression and fusion for cervical myelopathy. There were 10 cases of ossification of the posterior longitudinal ligament (OPLL) and eight cases of cervical spondylotic myelopathy (CSM). All patients received conservative treatment. Posttreatment full recovery was present in eight patients, and Grade 3/5 strength was documented in six in whom some weakness remained. Radiographic evaluation revealed that the C3-4 and C4-5 cord compression was significantly more severe in patients with paralysis than in those without paralysis. The incidence of paralysis was higher in patients with OPLL than in those with CSM (chi-square test, p = 0.03). The incidence of paralysis increased in parallel with the number of fusion levels (correlation coefficient r = 0.94). Multivariate analysis revealed that the final manual muscle testing (MMT) value was closely related to the preoperative MMT value (computed t value 4.17; p < 0.01) and preoperative Japanese Orthopaedic Association (JOA) score for cervical myelopathty (computed t value, 2.75; p < 0.05). Preexisting severe stenosis at C3-4 or C4-5 in patients with OPLL is a risk factor for paralysis. Preoperative muscle weakness and a low JOA score are factors predictive of poor recovery.

Anterior corpectomy and fusion with fibular strut grafts for multilevel cervical myelopathy

The authors conducted a study to investigate the long-term results and postoperative complications of a new surgical technique, fibular strut graft-assisted anterior corpectomy and fusion for multilevel (> four) cervical myelopathy. Multilevel anterior corpectomy and subsequent strut graft placement is considered a challenging procedure because of complications relating to graft dislodgment, pseudarthrosis, greater operative duration, and increased blood loss. The study comprised 100 patients with cervical myelopathy who underwent anterior corpectomy and fusion and fibular strut graft placement at more than four disc space levels between 1989 and 1998. Single-screw fixation was used in conjunction with the autologous strut graft. Preoperative and postoperative plain radiographs, computerized tomography myelograms, and magnetic resonance images were obtained for assessment of fusion status. All complications and outcomes were analyzed based on clinical records to evaluate the results of the technique. There were no cases of graft dislodgment. The graft union rate was 85%. Analysis of clinical data showed that pseudarthrosis had no adverse effect on the clinical results. Adjacent-level disc degeneration occurred in 12% of patients, but in all cases the patients were asymptomatic. In 9% of cases C-5 palsy was observed but it recovered spontaneously. There were no infections and no case of neurological deterioration. With this new graft technique, graft dislodgment, the major complication associated with strut graft surgery, was resolved completely. This simple technique involving single-screw fixation provided good results when used in conjunction with anterior decompression and strut graft fixation with a very low incidence of complications.

Experimental study of the participation of the vertebral endplate in the integration of bone grafts

The surgical technique of anterior vertebral arthrodesis has been modified by the introduction of cages in spinal surgery. The classical technique recommends removal of the vertebral endplate and exposure of bleeding cancellous bone. However, after the observation of cage subsidence during postoperative follow-up, the vertebral endplate is no longer removed, due to its greater mechanical resistance which can prevent cage subsidence. The mechanical characteristics of the vertebral endplate are well known, in contrast to its osteogenic potential, which was investigated in the present experimental study. The study was conducted on mongrel dogs of both sexes, which were submitted to anterior corpectomy at the cervical spine level. A cortico-cancellous bone graft removed from the tibia was used for the reconstruction of the vertebral segment, which was used with osteosynthesis plates. At the site of contact between the surface of the vertebral body and the bone graft, the vertebral endplate was completely removed and cancellous bone was exposed in the inferior vertebra, whereas in the superior vertebra of the arthrodesed vertebral segment only curettage was performed, and the vertebral endplate was preserved, as recommended for cage implantation. Twenty adult dogs of both sexes were divided into four experimental groups according to time of sacrifice (15, 30, 90, and 180 days). The consolidation of the bone graft with the vertebral body was evaluated by histology using hematoxilin-eosin and Gomori trichrome staining. In the interface between the bone graft and the vertebral body surface in which the vertebral endplate was not removed, graft consolidation was not observed in any of the group I animals (sacrificed after 15 days), and was observed in 1/5 animals of group II (30 days), in 2/5 animals of group III (90 days), and in 4/5 animals of group IV (180 days). In the interface between the graft and the vertebral body in which the vertebral endplate was removed, bone-graft consolidation was observed in all animals of all experimental groups (15, 30, 90, and 180 days). Bone-graft consolidation with the surface of the vertebral body was influenced by the removal or maintenance of the vertebral endplate. Due to the importance of this structure in current surgical procedures, this phenomenon deserves to be studied in more detail in order to understand the basic events involved in this process.

Anterior Cervical Spinal Cord Tethering after Anterior Spinal Surgery: Case Report

This is the first reported case of anterior cervical spinal cord tethering after anterior spinal surgery. A mechanistic hypothesis is presented to explain the observed phenomenon. A patient developed cervical myelopathy 2 years after multiple anterior cervical discectomies complicated by cerebrospinal fluid leakage. She demonstrated reflex and motor changes as well as neuropathic pain. An anterior corpectomy was performed, with opening of the dura and detethering of an arachnoid band and then fusion and plating. Reflex and motor changes improved, but pain did not. We hypothesize that mechanical deformation and scar formation after cerebrospinal fluid leakage may have led to tethering of the spinal cord.

Results of Surgical Treatment for Degenerative Cervical Myelopathy

This retrospective study involves 26 patients with degenerative cervical myelopathy who were surgically treated by anterior corpectomy, titanium mesh cage (TMC) filled with autogenous bone, and anterior plate +/- posterolateral plate and fusion. This study was conducted to determine the indications, efficacy, and complication rate associated with performing corpectomy to achieve anterior decompression of neural elements or for removing anterior lesions. This retrospective study involves patients with degenerative cervical myelopathy who were surgically treated by > or =2-level anterior corpectomy, TMC filled with autogenous bone, and anterior plate +/- posterolateral plate and fusion. The purpose was to evaluate and compare the results in terms of neurologic recovery and function and effectivity of TMC as a structural support. Twenty-six patients with degenerative cervical myelopathy who had surgical treatment and average 30 months (range, 24-52 months) follow up were included. The mean age was 64.9 years (range, 55-74 years) and average period between myelopathic symptoms and surgery was 2.8 years (range, 6 months-5 years). Preoperative evaluation of every patient consisted of anterior-posterior, lateral, bilateral oblique, flexion, and extension radiographs, computed tomography reconstructions and magnetic resonance imaging of the cervical spine, Doppler ultrasound of the carotid arteries, vertebral artery magnetic resonance angiography, neurologic examination, and electromyography. Degree of pre- and postoperative myelopathy was determined according to the scoring systems developed by Nurick and Japanese Orthopedic Association (JOA). Twelve patients had a mild balance problem and difficulty while walking but were able to perform their daily activities. Fourteen patients had spastic quadriparesis ambulating on either crutches or with wheelchairs. Of these, 11 experienced bladder disturbance as well. Surgical treatment in 18 patients consisted of anterior decompressive corpectomy, structural TMC, and anterior plate stabilization in 14 patients who had 2-level corpectomy. Posterior plate stabilization without laminectomy was added to this procedure in another 4 patients who had 3- or more level corpectomy. The remaining 8 patients had first laminectomy and posterolateral plate, then anterior corpectomy, TMC, and anterior plate on the same stage. Corpectomy levels were between C3 and T1, and anterior corpectomy, structural TMC, and anterior plating was the procedure that all patients had in common. Mean sagittal Cobb angle (C2-C7) was 9 degrees (range, 0-23 degrees) before surgery, 17.1 degrees (range, 11-22 degrees) on the third postoperative month, and 16.9 degrees (range, 10-22 degrees) at last follow-up. The difference in sagittal alignment on the third month and last follow up was not statistically significant (P > 0.05). Average preoperative Nurick score was 3.5 (range, 2-5) and JOA score was 7 (range, 1-14). Major and statistically significant neurologic recovery was within the first 3 months, and average Nurick and JOA scores at 3 months were 2 (range, 0-3) and 11 (range, 8-17) (P < 0.001), respectively. All patients had improved neurologic status at final follow up. As confirmed by plain radiographs and computed tomography reconstructions, solid fusion was achieved across the TMC with no settling or migration, and we had no implant-related complication or failure. As major complications, 1 (3.8%) early deep posterior infection developed but responded to early debridement and antibiotics. Also, 3 patients (11.5%) had transient C5 nerve root injury. At final follow up, all patients were able to ambulate without support and maintain their daily activities. Anterior decompression provides good neurologic recovery in patients with degenerative cervical myelopathy. TMC provides good structural support, and solid fusion can be achieved with TMC and anterior plate (for < or =2-level corpectomy) and/or posterior plate (> or =3-level corpectomy). There is increased risk of C5 nerve root injury when first laminectomy and posterolateral plate stabilization are performed.

The Management of Acute Thoracolumbar Burst Fractures with Anterior Corpectomy and Z-Plate Fixation

A retrospective review of a consecutive series of patients with acute thoracolumbar burst fractures who were surgically treated with an anterior corpectomy and fusion with anterolateral Z-plate fixation. To evaluate the clinical and radiographic success of the management of acute thoracolumbar burst fractures by corpectomy, structural grafting, and anterolateral internal fixation. Burst fractures are frequently associated with instability or neurologic deficit. Modern surgical procedures for these fractures have been performed via both anterior and posterior approaches. Anterior surgical treatment allows direct decompression of the neural elements and correction of deformity. Newer anterior instrumentation devices, combined with a structural graft, allow a stable construct that may obviate a posterior procedure. An anterior procedure generally requires fusion of only two levels compared to posterior fusion, which generally requires more. A retrospective review of a consecutive series of patients with thoracolumbar burst fractures treated with anterior surgery, strut graft, and fixation with a Z-plate was carried out. Fractures were considered acute if surgically treated within 30 days. Clinical and radiographic evaluation was performed on all 35 patients with acute thoracolumbar burst fractures. Surgical indications were incomplete neurologic deficit, segmental kyphotic deformity, or significant comminution. All patients with acute thoracolumbar burst fractures with spinal cord injury were treated with an intravenous steroid protocol and were operated on within 24 hours of admission unless medically precluded. Forty-six percent (16 of 35) of patients with acute thoracolumbar burst fractures presented with a neurologic deficit. All 16 patients with neurologic deficit demonstrated at least one Frankel grade improvement on final observation, with 11 (69%) patients demonstrating complete neurologic recovery. Thirty-three patients were treated with anterolateral instrumentation only. Twenty-nine of thirty patients demonstrated radiographic healing. Five were lost to follow-up observation. One patient required subsequent posterior fusion for increasing kyphotic deformity. There were no instances of hardware failure. Sagittal alignment was improved from a mean preoperative kyphosis of 18 degrees to 6 degrees at final follow-up observation. Anterior corpectomy, strut graft, and Z-plate fixation is an effective treatment for thoracolumbar burst fractures. It allows direct decompression of the spinal cord in the acute setting and was associated with a high rate of neurologic improvement, no instances of neurologic worsening in any case, and a low complication rate.

Treatment of thoracolumbar burst fractures with variable screw placement or Isola instrumentation and arthrodesis: case series and literature review.

The controversy of burst fracture surgical management is addressed in this retrospective case study and literature review. The series consisted of 40 consecutive patients, index included, with 41 fractures treated with stiff, limited segment transpedicular bone-anchored instrumentation and arthrodesis from 1987 through 1994. No major acute complications such as death, paralysis, or infection occurred. For the 30 fractures with pre- and postoperative computed tomography studies, spinal canal compromise was 61% and 32%, respectively. Neurologic function improved in 7 of 14 patients (50%) and did not worsen in any. The principal problem encountered was screw breakage, which occurred in 16 of the 41 (39%) instrumented fractures. As we have previously reported, transpedicular anterior bone graft augmentation significantly decreased variable screw placement (VSP) implant breakage. However, it did not prevent Isola implant breakage in two-motion segment constructs. Compared with VSP, Isola provided better sagittal plane realignment and constructs that have been found to be significantly stiffer. Unplanned reoperation was necessary in 9 of the 40 patients (23%). At 1- and 2-year follow-up, 95% and 79% of patients were available for study, and a satisfactory outcome was achieved in 84% and 79%, respectively. These satisfaction and reoperation rates are consistent with the literature of the time. Based on these observations and the loads to which implant constructs are exposed following posterior realignment and stabilization of burst fractures, we recommend that three- or four-motion segment constructs, rather than two motion, be used. To save valuable motion segments, planned construct shortening can be used. An alternative is sequential or staged anterior corpectomy and structural grafting.

Fibrous dysplasia of the cervical spine presenting as a pathological fracture

Fibrous dysplasia (FD) is an uncommon benign fibro-osseous abnormality of bone, of unknown aetiology and equal sex incidence, which is most commonly restricted to one bone (monostotic FD: MFD, 70%). Less commonly multiple bones are affected (polyostotic FD: PFD, 27%). Vertebral involvement is uncommon (4%), but more common with PFD (7 - 24%) than MFD (1%). Of 20 cases of FD involving the cervical spine, only three have represented MFD. Unlike cases associated with PFD, all cases presented with acute neck pain without significant neurological impairment after minor trauma. We present the case of a 35-year-old male with MFD who developed a pathological fracture of C3 following minor trauma. Radiographs showed collapse and typical 'ground glass' lucency of C3. CT revealed replacement of C3 cancellous bone by hypodense tissue extending into the right lateral mass. The cortex was thinned and fractured, and encroached upon the right foramen transversarium and spinal canal. Magnetic resonance imaging demonstrated hypo-intensity on both T1 and T2, with uniform contrast enhancement. Subtotal excision was achieved via an anterior C3 corpectomy, with residual FD left within the right lateral mass. Stability was achieved utilizing an iliac crest strut autograft, C2 - 4 plate-and-screws, and mobilization in a halo frame for 3 months. At 18 months, he remained asymptomatic and without deficit. Radiography, CT and MRI confirmed graft fusion without FD invasion, but with residual right lateral mass FD unchanged in size.

Posterior cervical fusion failure in three morbidly obese patients following circumferential surgery

Background The stability of multilevel anterior corpectomy with fusion (ACF) is often enhanced by simultaneous posterior fusion (PF) which provides a “posterior tension band.” Three morbidly obese patients undergoing circumferential surgery had posterior fusions performed without autogenous iliac crest graft to avoid donor site morbidity. Methods Three morbidly obese patients (300–350 lbs.), averaging 48 years of age, presented with rapidly progressive moderate/severe myelopathies. Magnetic resonance imaging (MRI) and computed tomography (CT) studies demonstrated severe ventral ossification of the posterior longitudinal ligament. Two to four level plated ACFs were performed utilizing fibula strut allograft and plates. Posterior spinous process wiring/fusion from C2-T1 were completed with braided titanium cables, fibula strut allografts, Inductive Conductive Matrix (a form of demineralized bone matrix), and allograft bone to avoid iliac crest donor site morbidity in such morbidly obese patients. Halo devices were utilized until fusion was documented on postoperative X-ray and 2D-CT studies subsequently obtained 3, 6, and up to 12 months postoperatively. Patients were followed an average of 3 years. Results Postoperatively, all 3 patients demonstrated mild residual myelopathy (Nurick Grade 0-I). Nevertheless, all 3 exhibited posterior pseudarthroses accompanied by anterior strut/plate extrusion (1 patient), partial anterior graft pseudarthrosis (1 patient), and a delayed strut fracture (1 patient). The first 2 patients required secondary posterior fusions performed with autogenous iliac crest graft, while the third fused with 6 months of additional bracing. Conclusions Following circumferential cervical procedures, posterior fusions failed in 3 morbidly obese patients where iliac crest autograft was omitted in an attempt to avoid donor site morbidity.

Anterior cervical dynamic ABC plating with single level corpectomy and fusion in forty-two patients.

Forty-two consecutive patients undergoing dynamic ABC plated one-level ACF utilizing iliac crest autograft (38 patients) and fibula allografts (four patients) were evaluated. The unique ABC slotted plate design allows for up to 10 mm of cephalad and 10 mm of caudad plate migration. To evaluate the incidence and etiology of complications in forty-two patients undergoing anterior cervical dynamic ABC plating (Aesculap, Tuttlingen, Germany), during one level anterior corpectomy with fusion (ACF). New York, USA. Serial dynamic X-ray and 2 Dimensional CAT Scan (2D-CT) studies, obtained 3, 6, and up to 12 months postoperatively, in 42 patients documented the presence of fusion or complications including plate or graft extrusion or pseudarthrosis. Four (9.5%) of 42 patients developed postoperative plate or graft-related complications during the average follow up interval of 34 months. One patient, with a plate/graft extrusion, required a second two level ACF with posterior wiring and fusion (PWF). Two patients with pseudarthroses and one patient with a delayed iliac crest strut fracture required secondary PWF. Effective arthrodesis and a low incidence of complications following one level ACF performed utilizing dynamic ABC plates were attributed to reduced stress shielding and greater graft compression afforded by the unique plate design. Applying dynamic ABC plates for one level ACF was biomechanically advantageous with low morbidity.

Anterior corpectomy and fusion for cervical myelopathy with fibular strut autograft

Anterior corpectomy and fusion for cervical myelopathy with fibular strut autograft

Delayed iliac crest autograft fractures following plated single-level anterior cervical corpectomy with fusion.

Recurrent cervical pain following single-level plated anterior corpectomy with fusion signaled delayed mid-iliac crest autograft fractures in four of 56 patients. Single-level anterior corpectomy with fusion used 15 fixed plates (Sofamor Danek) and 41 dynamic ABC plates (Aesculap). Patients in the fixed-plate and dynamic-plate groups averaged 46 and 48 years of age, respectively. Fusion was confirmed on both dynamic radiograph and two-dimensional CT studies an average of 4.5 months postoperatively. Two (13%) fixed-plated patients developed mid-iliac crest strut fractures 1 and 2 years postoperatively, whereas two (5%) dynamic-plated patients showed similar fractures 6 and 9 months following surgery. Immobilization in CTO orthoses resulted in fusion in one case, whereas three patients required secondary posterior wiring/fusion. Recurrent pain signaled delayed autograft strut fractures in four of 56 patients undergoing plated single-level anterior corpectomy with fusion.

Ossification of the cervical posterior longitudinal ligament: a review

Ossification of the cervical posterior longitudinal ligament (OPLL) represents a continuum beginning with hypertrophy of the posterior longitudinal ligament (PLL) followed by progressive coalescence of centers of chondrification and ossification. Early OPLL mimicking disc disease appears opposite multiple disc spaces associated with significant retrovertebral extension, helping to differentiate it from spondylosis. On computerized tomography examinations, the single- and double-layer signs indicate possible dural penetration with the increased potential for an intraoperative cerebrospinal fluid fistula during dissection. Direct ventral resection of OPLL in patients younger than 65 years of age is optimal and includes single- or multilevel anterior corpectomy with fusion, the latter accompanied by posterior fusion. For patients older than the age of 65 years, with a well-preserved cervical lordosis, laminectomy with or without fusion and/or laminoplasty may suffice in providing indirect dorsal decompression. Patients undergoing circumferential procedures with halo devices are managed with a specific anesthetic protocol, including awake intubation and positioning with intraoperative monitoring of somatosensory evoked potentials, electromyography, and the option of undergoing motor evoked potential monitoring. Intubation is maintained during the 1st postoperative night. When circumferential procedures are performed intubation is always maintained during the 1st postoperative night, and fiberoptic postoperative extubation is electively performed by specifically trained anesthesiologists when deemed appropriate. Patients exhibiting three or more major risk factors are considered candidates for delayed extubation and rarely, tracheostomy. Repeated anterior surgery, operations lasting more than 10 hours, involving four or more levels (including C-2), obesity, asthma, and blood transfusions of more than 4 U (1000-1200 ml) are all considered major risk factors.

Three-stage surgery in the management of severe rigid angular kyphosis.

There are conflicting data regarding the management of rigid kyphosis. None of the currently known techniques can completely correct severe kyphosis without resulting in residual deformity. Seven patients with local kyphosis exceeding 60 degrees were operated on to achieve complete correction of the deformity. The surgery consisted of total spondylectomy of the deformed vertebra and simultaneous application of compression-distraction forces to this area. The operation included three stages: The initial stage includes resection of posterior spinal elements and temporary fixation. In the second stage, an anterior corpectomy is performed to conclude the resection, and simultaneous antero-posterior correction is obtained. The final stage includes another posterior procedure to achieve a precise correction and to correct any compensatory curves. All patients were operated on using this technique in a single session. The mean preoperative and postoperative kyphosis angles were 76.1 degrees (range, 65 degrees -92 degrees) and 6 degrees (range, 0 degrees -13 degrees), respectively. Complete bony fusion was achieved after a mean follow-up period of 38 months (range, 26-52 months) without any neurological sequelae or significant loss of correction.

MACS-TL polyaxial screw XL. A new concept for increasing stability of ventral spondylodesis in the presence of dorsal injuries

The influence of additional dorsal structure damage on anterior stabilization of thoracolumbar fracture is still unknown. Screw cement enhancement is a possibility to reinforce the stability of anterior instrumentation. A new anchorage system has been developed for fixation of anterior stabilization devices, adapted through geometric optimization and the possibility of optional additional cementation after screw insertion in cases of poor bone quality. Is this enhancement strong enough to support a single anterior procedure such as the thoracoscopic technique and still compensate for dorsal instability? A biomechanical in vitro study simulating an anterior corpectomy, strut grafting, and overbridging stabilization with a dorsal laminectomy as dorsal structure damage was performed, and the primary stability parameters were evaluated with and without screw cement enhancement. The additional cementation enhanced the primary stability of the anterior instrumentation and compensated for dorsal instability.

Bone graft force in anterior cervical fusions without anterior plating

Bone graft force in anterior cervical fusions without anterior plating

Computed tomography validating bony ingrowth into fibula strut allograft: a criterion for fusion

Background context: Static and dynamic X-ray studies routinely determine whether or not fusion of a fibula strut allograft has occurred after multilevel anterior corpectomy with fusion (ACF) combined with posterior wiring and fusion (PWF). Purpose: Two-dimensional (2D) computed tomography (CT) studies were assessed for documentation of bony ingrowth into fresh frozen fibula strut allograft to constitute an additional sign of fusion. Study design/setting: This was a prospective, nonrandomized study, which was conducted at a university medical center. Patient sample: Eighteen patients with moderate to severe myelopathy undergoing circumferential cervical surgery for ossification of the posterior longitudinal ligament and spondylostenosis were evaluated. Outcome measures: Static and dynamic X-rays and 2D CT examinations were performed in 18 patients 3 and 6 months after circumferential cervical procedures. Methods: Fusion was assessed on static and dynamic X-rays, and 2D CT studies performed in 18 patients following average 2.9 level anterior corpectomy with fusion (ACF) with posterior wiring and fusion (PWF) (C2–T1) with halo application. Routine fusion criteria on static radiographs included the documentation of bony trabeculation and absence of bony lucency at the graft/vertebral end plate interface. Routine dynamic X-ray criteria of fusion mandated that less than 3.5 mm of translation, less than 20 degrees of angulation, and less than 1 mm of motion be observed between adjacent spinous processes. Here, a potential additional 2D CT criterion for fusion, progressive bony ingrowth into the central shaft of a fibula strut allograft, was investigated on 3 and 6 month postoperative 2D CT examinations using direct measurement of Hounsfield units. Telescoping (mm) was also differentiated from ingrowth into the bony shaft based on a comparison of immediate, 3 and 6 month postoperative CT studies. Results: Immediate postoperative baseline 2D CT studies revealed no bone within the central canal but an average of less than 1 mm of cephalad and 2.3 mm of caudad graft telescoping. Within 6 postoperative months, 2D CT studies demonstrated an average of 3.5 mm of superior and 4.6 mm of inferior bony ingrowth (confirmed by measuring 500 to 900 Hounsfield units) into the central fibula canal of 17 of 18 patients (94%). Seventeen had routine/dynamic X-ray and CT studies confirming fusion. Conclusions: Two-dimensional CT evidence of bony ingrowth into the central canal of fibula strut allografts after multilevel ACF/PWF provided an additional means of quantifying the extent of fusion.

Reoperation rates for acute graft extrusion and pseudarthrosis after one-level anterior corpectomy and fusion with and without plate instrumentation: etiology and corrective management

BACKGROUND Reoperation rates after one-level anterior cervical corpectomy with fusion (ACF) performed without and with plates need further evaluation. METHODS Reoperation rates for graft extrusion and symptomatic pseudarthrosis were analyzed following 48 nonplated (1989–1996) and 35 plated (1997–2000) one-level ACF. Preoperatively, patients typically exhibited mild/moderate myelopathy attributed to spondylostenosis and ossification of the posterior longitudinal ligament (OPLL). Thirty-five ACF were performed with plates: 3 Orion, 12 Atlantis, and 20 ABC Aesculap plates. Fusion was documented on both dynamic X-rays and 2- or 3-dimensional CT studies 3 and 6 months postoperatively, or until fusion occurred. Follow-up averaged 82 months for the nonplated patients, and 21 months for the plated patients. RESULTS Out of 48 nonplated patients, 3 developed immediate graft extrusions within 24 hours of surgery requiring graft replacement. Another 2 exhibited symptomatic pseudarthrosis 6 months postoperatively, and required secondary posterior wiring with fusion (PWF). In comparison, 1 of the 35 patients with plated one-level ACF developed plate displacement 6 weeks postoperatively, while 3 exhibited symptomatic pseudarthrosis 6 months after surgery, and required secondary posterior wiring and fusion (PWF). CONCLUSIONS Comparison of one-level ACF performed with and without plates showed that plating did not appear to reduce pseudarthrosis or graft extrusion rates.

From Postsurgical Imaging…

Marked superior and inferior migration of a dynamic plate after multilevel anterior corpectomy and fusion with posterior wiring (Fig. 1a) (Fig. 1b) 1 Epstein N.E. Circumferential surgery for the management of ossification of the posterior longitudinal ligament. J Spinal Disord. 1998; 11: 200-207 Crossref PubMed Scopus (53) Google Scholar , 2 Epstein N.E. The value of anterior cervical plating in preventing vertebral fracture and graft extrusion following multilevel anterior cervical corpectomy with posterior wiring/fusion. J Spinal Disord. 2000; 13: 9-15 Crossref PubMed Scopus (62) Google Scholar , 3 Epstein N.E. The management of one level anterior cervical corpectomy with fusion employing Atlantis hybrid plates preliminary experience. J Spinal Disord. 2000; 13: 324-328 Crossref PubMed Scopus (24) Google Scholar Fig. 1A 59-year-old man with moderate to severe spastic cervical myeloradicular syndrome (Nurick grade IV), caused by continuous ossification of the posterior longitudinal ligament was treated with anterior corpectomy C3–7 and anterior and posterior fusion. Fixation posteriorly was by wiring and anteriorly by a “dynamic” ABC Aesculap 80-mm-long plate. Such plates are unique in that the screws themselves can migrate up to 10 mm within the slots of the plate and because the “variable” screws are capable of toggling up to 34 degrees. (a) Lateral and (b) anteroposterior radiographs, taken 6 weeks after surgery, show that the plate had migrated 6 cm cephalad and 4 mm caudad within the slots of the plate (curved arrows). The screw angles superiorly and inferiorly remained at approximately 17-degree angles (double arrows, left panel). Four months after surgery, the patient appeared to have fused by three-dimensional computed tomography and by flexion/extension lateral stress films. Neurologically, he improved three Nurick grades to minimal residual (Nurick I) View Large Image Figure Viewer