Ajay Jawahar

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.

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.

Stereotactic Radiosurgery for Hemangioblastomas of the Brain

Summary Objective. To assess the effectiveness of stereotactic radiosurgery in achieving tumor control and improving survival in patients with hemangioblastoma, we evaluated results from patients who were managed at the University of Pittsburgh and the Mayo Clinic. Patients and Methods. Twenty-seven patients with 29 hemangioblastomas had stereotactic radiosurgery over a 10 year interval. The mean patient age was 32 years (range, 14–75 years). The tumor volumes varied from 0.36 to 27 ml (mean, 3.2 ml), and the mean tumor margin dose was 16 Gy (range, 11.7–20). Clinical and neuroimaging follow-up was obtained for all patients between 0.5 and 9 years (mean, 4 years) after radiosurgery. Results. At this assessment, 21 patients (79%) were alive and six (21%) had died. The median survival after radiosurgery was 6.5 years (actuarial 5 year survival=75.1±11.5%). The median survival from the initial diagnosis was 15 years. Twenty two of 29 evaluable tumors were controlled locally. The two-year actuarial control rate was 84.5±7.1% and at five years, 75.2±8.9%. Multivariate testing of factors affecting good outcome indicated that smaller tumor volume and higher radiosurgical dose (>18 Gy) were significant. Conclusion. For small to moderate size hemangioblastomas, multiple or recurrent tumors, and for patients who are not surgical candidates, radiosurgery is a safe and effective option to control disease and improve survival.

Adjuvant Stereotactic Radiosurgery for Anaplastic Ependymoma

Object: The purpose of this retrospective study is to evaluate the role of stereotactic radiosurgery using the Gamma Knife as an adjuvant to other modalities used in the treatment of malignant ependymomas of both children and adults and to assess its efficacy in terms of tumor control and overall survival. Method: Between 1987 and 1998, 22 patients in the age range of 1.5–65 years (mean age 22.3) with progressive anaplastic ependymoma were treated by stereotactic radiosurgery using the 201 source Co-60 Leksell Gamma Knife at the University of Pittsburgh. The irradiated tumor volume varied from 0.84 to 36.8 cm3 (mean 13.7). The median dose delivered to the tumor margin was 16.1 Gy (range 10–20), and the mean maximal dose was 32.2 Gy (range 20–40). The disease-free survival, the tumor control rate and the overall survival were recorded to evaluate the efficacy of radiosurgery. The median follow-up from radiosurgery was 21 months (range 4–84). Results: Median survival after radiosurgery was 2.2 years (46.6 ± 12.1% 5-year actuarial). Median survival from the initial diagnosis was 10.1 years (50.3 ± 12.5% at 5 years, 37.7 ± 14.4% at 10 years). Reduction or stabilization of the treated tumor was seen in 16 out of 22 (68%) patients. Forty-one percent of the patients eventually developed delayed distant cerebral recurrence outside the treated volume. The 5-year actuarial rates for local control and cranial control at any location were 62.3 ± 13.6% and 32.4 ± 10.8%, respectively. No complication occurred as a side effect of radiosurgery. Conclusion: For patients with locally recurrent or progressive anaplastic ependymomas, Gamma Knife stereotactic radiosurgery proved to be safe and effective as a salvage adjuvant therapy to achieve local tumor control and improve survival.

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.

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 patients 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.

Imaging the trigeminal nerve and pons before and after surgical intervention for trigeminal neuralgia.

OBJECTIVE To study the various imaging changes occurring in the trigeminal nerve and brainstem in patients before or after trigeminal neuralgia surgery. METHODS During a 7-year period, 275 patients with trigeminal neuralgia underwent high-resolution, contrast-enhanced magnetic resonance imaging (MRI) of the pons during gamma knife radiosurgery. Ninety-seven patients had no previous surgical intervention for trigeminal neuralgia, and 178 patients had undergone one or more previous procedures. Two independent observers, one of whom was blinded to patients’ clinical details, reviewed MRI scans retrospectively. The analysis of the independent observers was then correlated with all previous therapeutic interventions. RESULTS One hundred one MRI scans demonstrated no radiological changes related to trigeminal neuralgia, and 174 MRI scans exhibited some radiological abnormality. The average axial plane diameter of the nerve for all patients was 4 mm (range, 2–6 mm). In the group that had not undergone previous surgery, 65 patients (67%) exhibited vascular compression. In the 88 patients who had undergone previous microvascular decompression, 21 (24%) had evidence of a pontine infarction. Twenty-six patients experienced facial sensory loss, 22 (88%) of whom had undergone previous surgery with evidence of a pontine infarction (n = 11) or perineural scarring (n = 6). CONCLUSION The majority of patients who had undergone previous trigeminal neuralgia surgery demonstrated readily identifiable abnormalities of the trigeminal nerve or brainstem. The frequency of such changes correlated with the type and number of procedures. Evidence of vascular compression was detected in the majority of patients. Most patients with postoperative facial sensory loss demonstrate changes in the nerve or pons on MR images.

A Comparison of Surgical Approaches for the Management of Tremor: Radiofrequency Thalamotomy, Gamma Knife Thalamotomy and Thalamic Stimulation

Objective: Between April 1994 and January 1999, 39 stereotactic procedures for patients with intractable tremor were performed at the University of Pittsburgh Medical Center. A retrospective analysis of results of radiosurgical thalamotomy (n = 15), MR-guided stereotactic radiofrequency thalamotomy (n = 13), and deep brain thalamic stimulation (DBS; n = 11) was performed to study relative advantages and risks of these procedures. Methods: All options were discussed with the patients, but radiosurgery usually was performed in elderly patients with concurrent medical problems. Stereotactic thalamotomy and DBS was performed with MR guidance and macrostimulation. For radiosurgery, a median dose of 140 Gy (range 130–150 Gy) was delivered using a single 4-mm collimator. Results: Of the 13 patients who underwent radiofrequency thalamotomy, 5 had immediate complete arrest of tremor, 6 had a significant reduction and 2 had partial reduction. All 11 patients who underwent DBS had excellent control of tremor immediately after the procedure, and in longer-term follow-up 10/11 maintained excellent tremor control. Of the 12 evaluable radiosurgery patients, 10 noted excellent relief and 2 had partial relief. Conclusion: Stereotactic procedures for tremor control are safe and effective. Each procedure has specific advantages and disadvantages that are important for patient selection.

Gamma Knife Radiosurgery for Brain Metastases: Do Patients Benefit from Adjuvant External-Beam Radiotherapy? An 18-Month Comparative Analysis

Objective: To analyze 18 months of results of gamma knife stereotactic radiosurgery in the treatment of brain metastases and determine factors affecting outcome by examining the effectiveness of additional external-beam radiotherapy (XRT). Materials and Methods: Between January 2000 and September 2001, 61 patients with 103 tumors diagnosed as cerebral metastases were treated with gamma knife. Mean patient age was 57 years (range = 36–81). Lung carcinoma (55.7%) was the most common primary cancer, followed by melanoma (14.8%) and breast carcinoma (11.5%). Mean KPS of the patients was 70 (range = 50–90). Twenty-seven patients had solitary metastases while 34 had multiple tumors. Forty-three patients (59 tumors in total) received only radiosurgery, while 18 patients (44 tumors in total) had prior XRT. Tumor volume ranged from 0.5 to 33 cm3 (mean = 9.74 cm3). Mean marginal dose prescription to the tumor was 15 Gy (range = 11–21 Gy). Results: Median follow-up was 11 months. Twenty-one patients (34.4%) were alive at last follow-up and 40 (65.6%) had died. Seventeen deaths (42.5%) were reported to be due to progressive brain disease, while 23 deaths (57.5%) were due to uncontrolled primary. Control of the treated lesions was achieved in 45 patients (73.8%) and 84 tumors (81.6%). Mean overall survival of the patients is 8 months (range = 1–19 months). The actuarial 12-month tumor control rate using the Kaplan-Meier method for this series is 68.2 ± 0.06%. Results of the log-rank test revealed that younger age (<55 years), small tumor volume (<10 cm3), and increasing tumor dose (>15 Gy) correlated with improved brain disease-free survival (p < 0.05). Overall survival, local tumor control rate and the freedom from brain disease period (based on the appearance of new brain tumors after radiosurgery) were analyzed separately for the groups receiving radiosurgery alone and those with prior XRT to detect any additional benefit of XRT. No statistically significant difference was found between the two groups for any of the considered outcomes. Conclusion: Gamma knife stereotactic radiosurgery is a safe and effective treatment option for patients with cerebral metastases. It provides survival benefits and improves quality of life by achieving excellent control of the brain disease, irrespective of patients’ age or number of brain tumors. The addition of XRT in younger patients with small brain metastases does not improve survival and/or control of the brain disease.

Intradiscal electrothermal therapy (IDET) for low back pain in worker's compensation patients: can it provide a potential answer? Long-term results.

Objective This prospective study was conducted to evaluate improvements in pain and disability in a series of 53 consecutive workers compensation patients with low back pain (LBP) after treatment with the intradiscal electrothermal therapy (IDET) procedure. Materials and Methods All patients seen in the out-patient clinic of the Spine Institute of Louisiana for LBP of discogenic origin were screened for eligibility to receive IDET procedure. A total of 134 patients were treated using IDET for their discogenic LBP during the study period. Fifty-three patients presented to us via the workers compensation claim program. The outcomes of these 53 patients were analyzed statistically for the current study by physical examination and self-assessment questionnaires of pain and disability at baseline and at 12-months postprocedure. Pain and disability outcomes were assessed by visual analog scale (VAS) pain score and Oswestry disability index, respectively. Results The mean patient age was 41.83 years (range 20 to 61 y). Whites (52.8%), African-Americans (30.2%), and Hispanics (17%) formed the majority of population. Forty-nine percent were using narcotics. The first definitive end point was considered at 12 months after the procedure. Median follow-up period was 56 months (range 29 to 72 mo). A mean reduction (P<0.001) of 62.6% in the VAS score and 69.3% in the Oswestry scores was noted after IDET. The patients initial VAS and Oswestry scores (P<0.05) significantly affected the final outcomes. About 47.2% of the patients had some degree of economic productivity and only 7 (initial 26) consumed narcotic analgesics. Conclusions IDET procedure can be a useful, safe, and cost-effective option in the management of carefully selected workers compensation claimants with chronic LBP of discogenic etiology.