PEEK versus titanium cages in lateral lumbar interbody fusion: a comparative analysis of subsidence.

OBJECTIVE: The authors have provided a review of radiographic subsidence after lateral lumbar interbody fusion (LLIF) as a comparative analysis between titanium and polyetheretherketone (PEEK) cages. Many authors describe a reluctance to use titanium cages in spinal fusion secondary to subsidence concerns due to the increased modulus of elasticity of metal cages. The authors intend for this report to provide observational data regarding the juxtaposition of these two materials in the LLIF domain. METHODS: A retrospective review of a prospectively maintained database identified 113 consecutive patients undergoing lateral fusion for degenerative indications from January to December 2017. The surgeons performing the cage implantations were two orthopedic spine surgeons and two neurosurgeons. Plain standing radiographs were obtained at 1-2 weeks, 8-12 weeks, and 12 months postoperatively. Using a validated grading system, interbody subsidence into the endplates was graded at these time points on a scale of 0 to III. The primary outcome measure was subsidence between the two groups. Secondary outcomes were analyzed as well. RESULTS: Of the 113 patients in the sample, groups receiving PEEK and titanium implants were closely matched at 57 and 56 patients, respectively. Cumulatively, 156 cages were inserted and recombinant human bone morphogenetic protein-2 (rhBMP-2) was used in 38.1%. The average patient age was 60.4 years and average follow-up was 75.1 weeks. Subsidence in the titanium group in this study was less common than in the PEEK cage group. At early follow-up, groups had similar subsidence outcomes. Statistical significance was reached at the 8- to 12-week and 52-week follow-ups, demonstrating more subsidence in the PEEK cage group than the titanium cage group. rhBMP-2 usage was also highly correlated with higher subsidence rates at all 3 follow-up time points. Age was correlated with higher subsidence rates in univariate and multivariate analysis. CONCLUSIONS: Titanium cages were associated with lower subsidence rates than PEEK cages in this investigation. Usage of rhBMP-2 was also robustly associated with higher endplate subsidence. Each additional year of age correlated with an increased subsidence risk. Subsidence in LLIF is likely a response to a myriad of factors that include but are certainly not limited to cage material. Hence, the avoidance of titanium interbody implants secondary solely to concerns over a modulus of elasticity likely overlooks other variables of equal or greater importance.

Adjacent Segment Pathology After Treatment With Cervical Disc Arthroplasty or Anterior Cervical Discectomy and Fusion, Part 1: Radiographic Results at 7-Year Follow-Up.

BACKGROUND: Adjacent segment pathology (ASP) remains a concern following treatment with cervical disc arthroplasty (CDA) and anterior cervical discectomy and fusion (ACDF). Radiographic ASP (RASP) is ASP identified on imaging, which may or may not include clinical symptoms. The risk factors for development of RASP and its clinical effects remain controversial. In part 1 of a 2-part publication we evaluate the incidence and predictors of RASP as well as determine whether any association exists between RASP and patient-reported outcomes (PROs). METHODS: Data were prospectively collected during a US Food and Drug Administration randomized, multicenter, investigational device exemption trial comparing CDA (Mobi-C; Zimmer Biomet, Westminster, CO) with ACDF. Multiple post hoc analyses were conducted on RASP as it related to demographics and patient outcomes. Kaplan-Meier estimates of time to Kellgren-Lawrence (K-L) grade 3/4 were calculated separately for all groups. Multivariate Cox proportional hazard models were used analyze whether RASP was associated with patient preoperative demographic characteristics and preoperative and postoperative radiographic characteristics. The association of RASP with PROs was analyzed using generalized estimating equations and matched, retrospective cohort analysis. RESULTS: The incidence of grade 3/4 RASP was lower for patients treated with CDA when initial treatment was at 1 level (27% vs 47%, P < .0001) and at 2 levels (14% vs 49%, P < .0001). Kaplan-Meier estimates indicated significantly lower probability of grade 3/4 RASP over time for patients receiving CDA (P < .001). Treatment with ACDF, treatment of 1 level, higher age, body mass index, higher preoperative physical components score, and a lower Cobb angle were associated with elevated risk of grade 3/4 RASP. CDA was shown to be more effective than ACDF (64.4%; 95% CI = 50.9, 74.2; P < .0001) at preventing RASP. CONCLUSIONS: The incidence and risk of RASP is decreased when patients are treated with CDA compared with ACDF. Although the mechanism of CDA that generates this protective effect is not understood, PROs remain unaffected through 7 years despite changes in RASP.

Adjacent Segment Pathology After Treatment With Cervical Disc Arthroplasty or Anterior Cervical Discectomy and Fusion, Part 2: Clinical Results at 7-Year Follow-Up.

BACKGROUND: Adjacent segment pathology (ASP) following cervical disc arthroplasty (CDA) or anterior cervical discectomy and fusion (ACDF) is identified by imaging (RASP) or clinical symptoms (CASP). Clinical symptoms of CASP have been broadly defined, but subsequent adjacent-level surgeries are clear indicators of CASP. Current literature remains inconsistent in the incidence and potential predictors of CASP. Here, we will evaluate a robust data set for the incidence of CASP resulting in subsequent surgery, attempt to identify factors that might affect CASP, and analyze the association of CASP with patient-reported outcomes (PROS) and RASP. METHODS: Data were prospectively collected during a US Food and Drug Administration randomized, multicenter, investigational device exemption trial comparing CDA (Mobi-C, Zimmer Biomet, Westminster, CO) with ACDF. CASP was defined as any adjacent-level subsequent surgical intervention. Post hoc analyses were conducted on the incidence, time to CASP diagnosis, and relationship of CASP with patient demographics. Longitudinal retrospective case-control analysis was used to assess the correlation of CASP to PROs and radiographic adjacent segment pathology (RASP). RESULTS: Kaplan-Meier estimates indicated significantly lower probability of CASP over time for 1-level (P = .002) and 2-level (P = .008) CDA patients. Treatment with ACDF and younger age were associated with higher CASP risk. CDA was more effective than ACDF (70.5%; 95% CI = 45.1, 84.2; P < .0001) at preventing CASP. Case-control analysis indicated increased probability of CASP for patients with grade 3/4 RASP, but the difference was not statistically significant. When we pooled CASP patients, the median grade of RASP at the visit prior to surgery was 1, with only 6 patients presenting with grade 3/4 RASP. CONCLUSIONS: Patients treated with CDA have a lower incidence of CASP than do patients treated with ACDF, although the mechanism remains unclear. CASP and RASP remain uncorrelated in this large data set, but other predictive variables such as treatment, age, and number of levels should be further investigated.

Heterotopic Ossification After Cervical Total Disc Replacement at 7 Years-Prevalence, Progression, Clinical Implications, and Risk Factors.

BACKGROUND: Heterotopic ossification (HO) is a known risk following cervical total disc replacement (CTDR) surgery, but the cause and effect of HO are not well understood. Reported HO rates vary, and few studies are specifically designed to report HO. The effects on outcomes, and the risk factors for the development of HO have been hypothesized and reported in small-population, retrospective analyses, using univariate statistics. METHODS: Posthoc, multiple-phase analysis of radiographic, clinical, and demographic data for CTDR as it relates to HO was performed. HO was radiographically graded for 164 one-level and 225 two-level CTDR patients using the McAfee and Mehren system. Analysis was performed to correlate HO grades to clinical outcomes and to evaluate potential risk factors for the development of HO using demographics and baseline clinical measures. RESULTS: At 7 years, 1-level clinically relevant HO grades were 17.6% grade 3 and 11.1% grade 4. Two-level clinically relevant HO grades, evaluated using the highest patient grade, were 26.6% grade 3 and 10.8% grade 4. Interaction between HO and time revealed significance for neck disability index (NDI; P = .04) and Visual Analog Scale (VAS) neck pain (P = .02). When analyzed at each time point NDI was significant at 48-84 months and VAS neck at 60 months. For predictors 2 analyses were run; odds ratios indicated follow-up visit, male sex, and preoperative VAS neck pain are related to HO development, whereas hazard ratios indicated male sex, obesity, endplate coverage, levels treated, and preoperative VAS neck pain. CONCLUSIONS: This is the largest study to report HO rates, and related outcomes and risk factors. To develop an accurate predictive model, further large-scale analyses need to be performed. Based on the results reported here, clinically relevant HO should be more accurately described as motion-restricting HO until a definitive link to outcomes has been established.

Short-term outcomes of lateral lumbar interbody fusion without decompression for the treatment of symptomatic degenerative spondylolisthesis at L4-5.

OBJECTIVE Recently, authors have called into question the utility and complication index of the lateral lumbar interbody fusion procedure at the L4-5 level. Furthermore, the need for direct decompression has also been debated. Here, the authors report the clinical and radiographic outcomes of transpsoas lumbar interbody fusion, relying only on indirect decompression to treat patients with neurogenic claudication secondary to Grade 1 and 2 spondylolisthesis at the L4-5 level. METHODS The authors conducted a retrospective evaluation of 18 consecutive patients with Grade 1 or 2 spondylolisthesis from a prospectively maintained database. All patients underwent a transpsoas approach, followed by posterior percutaneous instrumentation without decompression. The Oswestry Disability Index (ODI) and SF-12 were administered during the clinical evaluations. Radiographic evaluation was also performed. The mean follow-up was 6.2 months. RESULTS Fifteen patients with Grade 1 and 3 patients with Grade 2 spondylolisthesis were identified and underwent fusion at a total of 20 levels. The mean operative time was 165 minutes for the combined anterior and posterior phases of the operation. The estimated blood loss was 113 ml. The most common cage width in the anteroposterior dimension was 22 mm (78%). Anterior thigh dysesthesia was identified on detailed sensory evaluation in 6 of 18 patients (33%); all patients experienced resolution within 6 months postoperatively. No patient had lasting sensory loss or motor deficit. The average ODI score improved 26 points by the 6-month follow-up. At the 6-month follow-up, the SF-12 mean Physical and Mental Component Summary scores improved by 11.9% and 9.6%, respectively. No patient required additional decompression postoperatively. CONCLUSIONS This study offers clinical results to establish lateral lumbar interbody fusion as an effective technique for the treatment of Grade 1 or 2 degenerative spondylolisthesis at L4-5. The use of this surgical approach provides a minimally invasive solution that offers excellent arthrodesis rates as well as favorable clinical and radiological outcomes, with low rates of postoperative complications. However, adhering to the techniques of transpsoas lateral surgery, such as minimal table break, an initial look-and-see approach to the psoas, clear identification of the plexus, minimal cranial caudal expansion of the retractor, mobilization of any traversing sensory nerves, and total psoas dilation times less than 20 minutes, ensures the lowest possible complication profile for both visceral and neural injuries even in the narrow safe zones when accessing the L4-5 disc space in patients with degenerative spondylolisthesis.

Preliminary Results of Bioactive Amniotic Suspension with Allograft for Achieving One and Two-Level Lumbar Interbody Fusion.

BACKGROUND: Bone graft material for lumbar fusion was historically autologous bone graft (ABG). In recent years alternatives such as allograft, demineralized bone matrix (DBM), ceramics, and bone morphogenetic protein (BMP) have gained favor, although the complications of these are not fully understood. Bioactive amniotic suspension (BAS) with allograft is a new class of material derived from human amniotic tissue. METHODS: Eligible patients receiving a one or two level lumbar interbody fusion with Nucel, a BAS with allograft, were contacted and scheduled for a mininmim 12 month follow-up visit. Patients were evaluated for fusion using CT's and plain radiographs. Clincal outcomes, including ODI, VAS back and leg were collected, as well as comorbidities including BMI, smoking status, diabetes and previous lumbar surgery. RESULTS: One-level patients (N=38) were 71.1% female with mean age of 58.4 ± 12.7 and mean BMI of 30.6 ± 6.08. Two-level patients (N=34) were 58.8% female with mean age of 49.3 ±10.9 and mean BMI of 30.1 ± 5.82. Kinematic fusion was achieved in 97.4% of one-level patients and 100% of two-level patients. Baseline comorbidities were present in 89.5% of one-level patients and 88.2% of two-level patients. No adverse events related to BAS were reported in this study. CONCLUSION: Fusion status is evaluated with many different biologics and varying methods in the literature. BAS with allograft in this study demonstrated high fusion rates with no complications within a largely comorbid population. Although a small population, BAS with allograft results were encouraging for one and two-level lumbar interbody fusion in this study. Further prospective studies should be conducted to investigate safety and efficacy in a larger population.

Symptomatic adjacent segment disease after cervical total disc replacement: re-examining the clinical and radiological evidence with established criteria.

BACKGROUND CONTEXT: Although several publications in the last decade have proved equality in safety and efficacy of the total disc replacement (TDR) to the anterior fusion procedure in cervical spine, the claim that TDR may reduce the incidence of adjacent segment disease (ASD) has not been corroborated by clinical evidence. PURPOSE: We attempt to predict the true incidence of symptomatic ASD after TDR surgery in the cervical spine at one or two levels at a median follow-up period of 4 years. STUDY DESIGN: A total of 763 patients were screened to participate in four different Food and Drug Administration device exemption trials for artificial cervical disc replacement at three collaborating institutions. Two hundred seventy-one patients qualified and enrolled in the trials. One hundred seventy-three randomized to receive artificial disc replacement surgery, and 167 have completed a 4-year or longer follow-up. OUTCOME MEASURES: Patients experiencing cervical radiculopathy symptoms in the follow-up period were worked-up with clinical examinations, magnetic resonance imaging of the cervical spine, and other diagnostic studies. Once a clinical correlation was established with the imaging evidence of adjacent segment degeneration, a careful record was maintained to document the subsequent medical and/or surgical treatment received by these patients. Statistical analysis was performed to determine the true incidence of and factors affecting the ASD after cervical disc replacement in these patients. RESULTS: Twenty-six patients (15.2%) were identified to satisfy our criteria for ASD at the median follow-up of 51 months, with the annual incidence of 3.1% as calculated by life tables. The actuarial 5-year freedom from ASD rate was 71.6%±0.6%, and the mean period for freedom from ASD was 70.4±2.1 months. CONCLUSIONS: The incidence of symptomatic ASD after cervical TDR is 3.1% annually regardless of the patient's age, sex, smoking habits, and design of the TDR device. The presence of osteopenia and lumbar degenerative disease significantly increase the risk of developing ASD after anterior cervical surgery.

Factors affecting the incidence of symptomatic adjacent-level disease in cervical spine after total disc arthroplasty: 2- to 4-year follow-up of 3 prospective randomized trials.

STUDY DESIGN: Prospective randomized clinical trials. OBJECTIVE: To compare the outcome data with respect to clinical success rates and incidence of adjacent level disease (ALD) in patients after total disc arthroplasty (TDA) or anterior cervical fusion (ACDF) for 1- and 2-level cervical disc disease. SUMMARY OF BACKGROUND DATA: Previously published studies have provided evidence that ACDF procedure for cervical degenerative disc disease (DDD) may increase the stress on the nonoperated adjacent cervical segments, thus possibly increasing the risk of degeneration at these levels. The theoretical assumption that TDA may reduce the incidence of future ALD by preserving motion at the affected segments has, however, never been validated by clinical evidence. METHODS: One hundred seventy patients with established symptomatic cervical disc disease at 1 or 2 levels participated in 3 prospective randomized clinical trials at 2 institutions. Participating subjects were randomized to receive TDA (treatment; n = 113) or ACDF (control; n = 57) by 6 independent investigating surgeons. Visual analogue pain scores (0-100), Neck Disability Index, neurological examination, and cervical spine radiographs were collected at enrollment and then 6 weeks and 3, 6, 12, 24, 36, and 48 months after surgery. Patients with persistent symptoms during the follow-up period were investigated for adjacent segment disease (ASD) with computed tomography/magnetic resonance imaging of the cervical spine, neurophysiology, and subsequent active interventions. RESULTS: At the median follow-up of 42 months (range: 28-54 months), 9 (14.3%) ACDF and 19 (16.8%) TDA patients developed and were actively treated for ASD. Osteopenia dust energy x-ray absorptiometry T scores of -1.5 to -2.4) (P = 0.04; 95% confidence interval [CI]: 0.007-0.223) and concurrent lumbar degenerative disease (P = 0.02; 95% CI: 0.003-0.196) significantly increased the risk of ASD. CONCLUSION: The risk of developing adjacent segment degeneration was equivalent at median 38 months after both ACDF and TDA procedures in cervical DDD. Osteopenia and concurrent lumbar DDD significantly increase the risk of ALD.

The use of osteo-conductive stem-cells allograft in lumbar interbody fusion procedures: an alternative to recombinant human bone morphogenetic protein.

UNLABELLED: The use of autogenous bone graft in spinal fusion is progressively declining. Different allografts including the human bone morphogenetic protein have been proposed to facilitate fusion rates but are associated with various adverse effects. Osteocel belongs to a new class of allograft tissue material that is a re-absorbable biomaterial with allogenic mesenchymal stem cells. The purpose of the present retrospective study was to analyze the clinical effectiveness of mesenchymal stem cells allograft (Osteocel") to achieve radiological arthrodesis in adult patients undergoing lumbar interbody fusion surgery for different indications. Fifty-two consecutive patients received lumbar interbody fusion at one (69%) or two contiguous (31%) levels of lumbar spine for various indications. The mean age was 50 (range, 27 to 77) years; 60% were females; 43% were habitual smokers and 21% had previously failed surgery at the index level(s). OUTCOME MEASURES: Radiographic analyses of fusion by plain films and CT scans. Procedures performed were circumferential fusion (67%), ALIF (17%) and TLIF (16%). Followup radiographic data was analyzed to establish arthrodesis versus failure (pseudarthrosis), number of months until achievement of fusion, and possible factors affecting the fusion rate. Followup ranged from 8 to 27 (median, 14) months. Solid arthrodesis was achieved in 92.3% of patients at median followup time of 5 months (95% Cl; range, 3 to 11 months). Kaplan-Meier survival curves and Mantle-Cox test were conducted to assess the effect of various factors on the rate of fusion. Statistics showed that increasing age (older than 50 years) (p = 0.017) and habitual smoking (p = 0.015) delayed the fusion time and increased the risk of pseudarthrosis. The use of Osteocel allograft is safe and effective in adult patients undergoing lumbar interbody spinal fusion procedure. Increased age and habitual smoking delays fusion but gender, previous surgery at the index level, type of procedure and number of levels do not affect the fusion rates.

Cervical ganglioneuroma in an adult man: case report and literature review of a rare occurrence.

OBJECTIVE AND IMPORTANCE: Ganglioneuromas are rare benign tumors of the neural crest occurring in early childhood. They are occasionally diagnosed in young adults due to their mass-effect on adjacent structures. We report a case of ganglioneuroma incidentally diagnosed in an adult man. CLINICAL PRESENTATION: A 41-year-old man presented with left-sided cervical radiculopathy symptoms due to degenerative disc disease at the C5-6 and C6-7 levels. The diagnostic radiology work-up revealed a mass in the left side of the neck between the carotid artery and jugular vein. INTERVENTION: Surgical excision of the mass was performed and the histological diagnosis of ganglioneuroma was established. The patient developed left-sided Horner's syndrome post-operatively. CONCLUSION: The present case suggests that these tumors may have insidious presence in the adult population, and therefore, should be considered in the differential diagnosis of a lateral neck mass in asymptomatic adult patients.

Total disc arthroplasty does not affect the incidence of adjacent segment degeneration in cervical spine: results of 93 patients in three prospective randomized clinical trials.

BACKGROUND CONTEXT: Advancements in the philosophy of "motion preservation" have led to the use of total disc arthroplasty (TDA) as an alternative to fusion for degenerative disc disease (DDD) in the cervical spine. A commonly proposed theory is that TDA could reduce the incidence of adjacent segment disease. All the published clinical studies for TDA discuss the "equal efficacy" results of different investigational device exemption (IDE) trials between TDA and anterior cervical discectomy and fusion (ACDF) but have not addressed the issue of adjacent segment disease. PURPOSE: To present the comparison of outcome data with respect to clinical success rates, symptom-free period, and incidence of adjacent segment disease in 93 patients with one- and two-level cervical DDD treated with TDA or ACDF in three different Food and Drug Administration (FDA) investigational trials. STUDY DESIGN: Prospective, randomized, FDA IDE trials. PATIENT SAMPLE: Ninety-three patients with established symptomatic one-or two-level cervical disc disease who failed to respond to conservative treatment were randomized to receive TDA (59) or ACDF (34) as part of clinical trials involving three different artificial discs at our institution. Subjects were blind to the assigned group until after the surgery. OUTCOME MEASURES: Visual analog pain score (VAS), Neck Disability Index, and cervical spine radiographs were collected at 6 weeks and at 3, 6, 12, 24, 36, and 48 months after surgery. METHOD: Success of the index surgery was assessed based on outcome measures at the seven data points. Success was defined as reduction by more than 30 points in both VAS and Neck Disability Index, absence of neurological deficits, and no further intervention at the index level. Adjacent segment disease was established by radiology, neurophysiology, and subsequent interventions administered to the patients. RESULTS: At median follow-up of 37 months (range, 24-49 months), 64 (25 ACDF and 39 TDA) patients satisfied the criteria for clinical success. Neck Disability Index was a better predictor of outcome than pain score (p<.05). Sixteen percent of TDA patients and 18% ACDF patients developed adjacent segment degeneration and were treated actively (p=.3). Concurrent lumbar DDD significantly increased the risk of adjacent segment degeneration (p=.01). Age, gender, smoking habits, and number of levels at index surgery had no predictive value. CONCLUSION: Total disc arthroplasty is equivalent to ACDF for providing relief from symptoms in the treatment of one- and two-level DDD of cervical spine. The risk of developing adjacent segment degeneration is equivalent after both procedures but is significantly higher in patients with concurrent DDD in lumbar spine.

Delayed hyper-reactivity to metal ions after cervical disc arthroplasty: a case report and literature review.

STUDY DESIGN: Anecdotal case report. OBJECTIVE: To report a very interesting and perplexing complication of cervical total disc arthroplasty that has not been previously reported in literature. SUMMARY OF BACKGROUND DATA: Although there has been increasing interest in the field of artificial disc replacement to treat cervical degenerative disc disease, not much has been mentioned in the literature about the potential complications of the disc itself. We encountered a delayed complication in 1 patient that has not been reported in the literature. METHOD: Thirty-nine-year-old white woman received total disc arthroplasty for herniated intervertebral disc at C5-C6 level uneventfully. She had recurrence of symptoms 9 months after the procedure and failed to respond to conservative measurements. Imaging revealed soft tissue mass posterior to the implanted disc encroaching the spinal cord. RESULTS: Surgical explantation and exploration of the disc space revealed thick layer of abnormal hyaline cartilaginous tissue with chronic inflammatory debris. The patient had complete resolution of symptoms after the revision surgery. CONCLUSION: Although there is increased enthusiasm about motion preservation technology and disc replacement surgery for intervertebral disc herniation, unexpected complications like the present case need to be shared within the scientific community to better understand the risks associated with these new and promising devices.

Choice of plate may affect outcomes for single versus multilevel ACDF: results of a prospective randomized single-blind trial.

BACKGROUND CONTEXT: Conflicting views exist according to the individual philosophy about various plate designs that can be used in anterior cervical discectomy and fusion (ACDF) to achieve clinical and radiological improvement within shortest time period. No prospective randomized study has ever been conducted to clarify the relationship between clinical outcomes, fusion rates, and the choice of plate (static vs. dynamic design). PURPOSE: To compare the clinical and radiological outcomes of patients treated with one-level or multiple levels ACDF using cervical plates of dynamic (slotted-holes) versus static (fixed-holes) design. STUDY DESIGN: Single masked, prospective, randomized study. PATIENT SAMPLE: Over a 4-year period, 66 patients (M:F=37:29) had ACDF using either dynamic (n=33) or static (n=33) plates for intractable radiculopathy as the result of degenerative cervical spine disease. Overall, 28 patients had single-level fusion and 38 had two or three levels fused. OUTCOME MEASURES: Visual Analogue Pain scores (VASs), Neck Disability Index (NDI), and radiological criteria of established fusion. METHODS: The qualifying subjects were randomized to receive ACDF using either fixed-holes (static) or the slotted-holes (dynamic) anterior cervical plates. Clinical and radiographic data were collected and analyzed. Paired-sample t test was used to correlate clinical and radiological outcomes and General Linear Model Analysis of Variance (GLM ANOVA) with repeated measures was used to detect outcome differences between the two groups for single and multiple fusions. RESULTS: At a mean follow-up of 16 months (range, 12-24), 49 patients (73.7%) had clinical success and 56 (85%) showed radiological fusion. Although clinical success was a predictor of fusion (p=.043), the reverse was not true (p=.61). In single-level fusion, no statistical difference of outcome was observed between the two groups but multilevel fusions with dynamic plate showed significantly lower VAS and NDI than those with static plates (p=.050). CONCLUSIONS: Although clinical improvement is a good predictor of successful ACDF, radiological evidence of fusion alone is not reliable as a parameter of success. The design of plate does not affect the outcomes in single-level fusions but statistics indicate that multiple-level fusions may have better clinical outcome when a dynamic plate design is used.

Implant design may influence delayed heterotopic ossification after total disk arthroplasty in lumbar spine.

BACKGROUND: As total disk arthroplasty (TDA) gains increasing acceptance as an alternative to fusion for degenerative disk disease of the lumbar spine, new complications are encountered by the physicians during and after the procedure. We hereby report a complication after TDA in the lumbar spine that is in variance from previously proposed theories and suggests the possibility of implant design as one of the etiologic factors. The purpose of the present submission is to report a case of delayed heterotopic ossification (HO) after TDA that suggests that the keel-based design of the implant might have contributed to the etiology. CASE DESCRIPTION: The patient underwent TDA for L3-4 degenerative disk disease and had fusion surgery for L5-S1 disease about 6 months later. During follow-up, development of significant HO was noticed at the L3 and L4 level. Radiologic studies revealed the origin of HO to be the keel cut made in the body of L3 to accommodate the keel-based artificial disk. CONCLUSION: The exact etiology of HO after TDA is not clear. The presented anecdote points toward vertebral body trauma due to the design of the implant as a possible factor that needs to be studied more elaborately.

Comparison of pressure effects on adjacent disk levels after 2-level lumbar constructs: fusion, hybrid, and total disk replacement.

BACKGROUND: With increasing advocacy for the use of TDR procedure as a surgical alternative to fusion in the management of lumbar DDD, intradiskal pressures at the adjacent levels of spine have generated considerable interest. The common belief is that adjacent-level disk pressures will be lower after a TDR as opposed to conventional fusion. The aim of this study is to present the effect of different constructs on adjacent-level disk pressures in lumbar spine. We hypothesized that the adjacent-segment disk pressures after 1- and 2-level TDR and/or a fusion-TDR hybrid procedure will show significant variance within physiological range of motion. METHODS: Six adult spine segments T12-S1 with intact ligaments were harvested from cadavers and held firmly in a specially designed fixture. Intradiskal pressures, in motions of flexion, extension, and lateral bending, at L2-L3 and L3-L4 were measured using needle transducers after 2-level TDR L4 through S1, hybrid procedure, and 2-level fusion L4-S1 with femoral ring allograft and pedicle screws. RESULTS: The pressures with lateral bending were not significantly lower than those with flexion and extension at both levels (P = .18). Although TDR and hybrid specimens recorded slightly lower pressures specifically during lateral bending, no statistical difference in pressures could be detected when movements were combined with various procedures. CONCLUSION: Contrary to the assumed hypothesis, the pressures at the adjacent-level disks (L3-4 and L2-3) did not depend upon the stabilization procedure (2-level disk replacement, hybrid, or 2-level fusion) performed after 2-level diskectomy in the lumbosacral spine.

Intraspinal meningioma in a 101-year old: should age determine the aggressiveness of intervention?

BACKGROUND: Intraspinal meningiomas are less frequent in occurrence as compared with their intracranial counterparts. Typical presentation is onset of new spinal pain followed by other deficits in the sixth decade of life. Although total surgical removal is the optimum treatment, various tumor- and patient-related factors can determine the aggressiveness of the surgical endeavor. We present our experience of diagnosis and management of cervical intraspinal meningioma in the oldest reported patient (101 years) with an atypical clinical presentation and remarkable dissociation between clinical and radiologic findings. METHOD: The patient, a 101-year-old woman, experienced progressive weakness in her legs. Motor examination revealed no definite weakness. There was stocking type sensory loss to just below the knees bilaterally. The MRI of the cervical spine showed an enhancing mass anterolateral to the cord at the region C7 through T1. It markedly compressed the cord. RESULT: The tumor was removed in total, and the dural attachment was thoroughly coagulated. CONCLUSION: The presented experience supports the belief that, in spinal meningiomas, a good clinical outcome can be expected even in patients who may be less than perfect candidates for an aggressive surgical approach.

Primary osteoblastic osteosarcoma in an elderly female: a case report of perplexing presentation.

With advances in imaging technology and increased alertness by clinicians, the reported incidence of primary vertebral osteosarcoma (PVOS) has increased in recent times and, therefore, the importance of its correct diagnosis has repeatedly been emphasized. One such case of PVOS is reported, that presented with insidious clinical, radiological and pathological findings, resulting in a slightly delayed final diagnosis and treatment.

Minimally invasive treatments of osteoporotic vertebral compression fractures: vertebroplasty and kyphoplasty.

Although nonsurgical treatment of osteoporotic vertebral compression fractures, including medication, exercise, bracing, and bed rest, have been reasonably effective, vertebroplasty and kyphoplasty have evolved as valuable adjunctive treatment options. Over the past decade, vertebroplasty, which involves the percutaneous injection of bone cement directly into the fractured vertebral body, has been used as a treatment for painful osteoporotic vertebral body compression fractures, a leading cause of morbidity in the elderly. Kyphoplasty, another minimally invasive procedure that allows for correction of spinal deformity and for controlled cement filling of the fractured vertebral body, involves the percutaneous cannulation of the vertebral body followed by the placement of an inflatable bone tamp. Reported results for both vertebroplasty and kyphoplasty suggest rapid improvement in pain and physical functioning in patients with osteoporotic vertebral compression fractures. Kyphoplasty allows for low-pressure cement injection and affords the opportunity to correct spinal deformity. Further study is required to define the precise indications, timing, and relative merits of these techniques.