We identified a p-cumate degrading gene cluster (designated cmt) with a novel organization in our genomic studies of the terpene-degrading Rhodococcus sp. strain T104. The mutant strain SN140, isolated for the inability to grow on p-cumate, accumulates 2,3-dihydroxy-p-cumate as identified by liquid chromatography-mass spectrometry and 300 MHz proton nuclear magnetic resonance spectroscopy. Reverse transcriptase polymerase chain reaction experiments showed that the cmt genes are operonic and induced specifically by growth on p-cumate. This report is the first example of identifying the genes for p-cumate degradation in a gram-positive organism based on functional data. PMID: 17233717 [PubMed - in process]  Full Article

Zwitterionic silver nitrate salts of 1-(1-methyl-3-imidazolio)propane-3-sulfonate, 1-(1-methyl-1-pyrrolidinio)propane-3-sulfonate, and 1-(4-methyl-4-morpholio)propane-3-sulfonate have been prepared and tested as carriers for facilitated olefin transport membranes in the separation of ethylene/ethane, propylene/propane, and C(4) mixtures. The interactions of olefins with silver ions bound to sulfonate groups were investigated by FTIR spectroscopy as well as the correlation between the binding affinity of olefins and facilitated transport. PMID: 17171729 [PubMed - as supplied by publisher]  Full Article

BACKGROUND CONTEXT: There has been recent enthusiasm regarding the potential positive effects of statins on bone. Statins vary in their ability to influence bone activity. Simvastatin has been shown in experimental models to stimulate bone acting growth factors and enhance bone formation. PURPOSE: The potential efficacy of Simvastatin in enhancing spinal fusion was evaluated in a rabbit posterolateral intertransverse process fusion model. STUDY DESIGN/SETTING: Posterior lumbar intertransverse process spinal fusion performed on New Zealand White rabbits. PATIENT/STUDY SAMPLE: 44 New Zealand White rabbits. OUTCOME MEASURES: Spinal fusion as determined by manual palpation testing and fine detail radiography. Bone fusion mass volume and density as determined by CT scan imaging. METHODS: Forty-four New Zealand White rabbits underwent posterolateral intertransverse process spine fusion using autogenous iliac crest bone graft. Simvastatin was administered orally in 20 animals and the serum lipid profile quantified in test and control animals. The animals were euthanized 9 weeks following index surgery and the lumbar spine was harvested. Spinal fusion was determined by manual palpation testing and fine detail radiography. The volume and density of the bone fusion mass was quantified by computed tomography. RESULTS: Drug treatment for 9 weeks caused a reduction in serum lipid biochemical markers when compared with controls. The spinal fusion rate, as judged by manual palpation testing (13.0% control group, 16.6% Simvastatin group) and fine detail radiography, was not significantly different comparing treatment with control animals. Accordant with the assessment of spinal fusion, there was no statistically significant effect on the volume of the fusion mass (1,224.7+/-98.7 mm(3) in the control group and 1,075.9+/-66.3 mm(3) in the Simvastatin group), the density of bone in the lumbar spine or that in the formed fusion mass. CONCLUSIONS: Systemic use of Simvastatin caused a reduction in lipid biochemical parameters in treated animals. Successful spinal fusion as judged by manual palpation testing and fine detail radiography was not significantly different in treated versus untreated animals. The bone volume density of the formed fusion mass was not significantly different in treated versus untreated animals. There did not appear to be a significant advantage or disadvantage to the use of Simvastatin rabbit posterolateral spinal fusion. The potential positive effects of statins on bone require further study. PMID: 16825044 [PubMed - indexed for MEDLINE]  Full Article

BACKGROUND CONTEXT: Recombinant human bone morphogenetic protein-2 (rh-BMP2) has become popular for augmenting spine fusion in the lumbar and cervical spine. Concerns exist, however, over bone morphogenetic protein (BMP)-stimulated soft-tissue swelling and bone growth stimulation in areas where bone is not desired, especially as the material "leaks" into such spaces. The most detrimental effects of such leakage might be airway compromise, while heterotopic bone formation into the spinal canal has been reported in animal and human studies. Fibrin glue has been used as a carrier of many osteoinductive materials; however, its efficacy at modulating the clinical effects of BMP are not known. The amorphous nature of fibrin glue makes it a candidate to control diffusion of BMP and possibly limit bone formation by limiting BMP diffusion to areas where such bone is not desired. PURPOSE: To evaluate the use of fibrin glue to limit BMP diffusion and BMP-stimulated bone growth. STUDY DESIGN/SETTING: This is an in vitro basic science study and an in vivo prospective randomized animal study. STUDY SAMPLE: Eighteen Lewis rats. OUTCOME MEASURES: In vitro study: Enzyme-linked immunosorbent assay measurement of rh-BMP2 concentration in saline. In vivo study: At day 60, rats were evaluated for neurologic deficits before sacrifice. Spines were harvested, and the following studies were performed: 1) manual testing for fusion and bone growth; 2) X-ray evaluation; 3) Micro-computed tomography (micro-CT) scans. METHODS: In vitro study: Collagen sponges soaked with BMP at two different concentrations were incubated in saline solution with and without encapsulation by fibrin glue. Saline BMP concentrations were measured at consecutive time points. In vivo study: A rat fusion model using rh-BMP2 for fusion has been developed and tested with resultant100% fusion in over 100 rats. Lewis rats were divided into two groups and treated as follows: I: Exposure of L4-L5 transverse processes, decortication, and placement of BMP sponge in the lateral intertransverse space. II: Exposure and decortication as above and placement of fibrin glue before BMP sponge placement. RESULTS: In vitro study: Peak rh-BMP2 concentrations in saline were 20% and 45% of the maximum possible for fibrin glue encapsulated sponges and controls, respectively, with a more gradual increase to peak concentration in samples encapsulated in fibrin glue. In vivo study: No rats exhibited any neurologic deficits. X-rays revealed at least partial bone formation in all rats. Manual testing of intertransverse fusion spines revealed 100% fusion in rats treated with BMP only, whereas rats treated with fibrin glue before placement of BMP sponges revealed only one possible fusion. Posterior-lateral bone formation was present on X-ray in both groups, and micro-CT imaging revealed bridging bone from transverse processes to the BMP-stimulated bone in the control groups. In spines treated with fibrin glue before rh-BMP2 placement, bone formation could still be seen within the soft tissues; however, bridging bone connecting to the transverse processes was either significantly decreased or not present. CONCLUSIONS: Fibrin glue can limit rh-BMP2 diffusion. Also, because it limited bone formation at the transverse processes, it can be inferred that fibrin glue can limit bone formation when used to separate areas of desired bone formation from areas where bone formation is not desired. PMID: 16825045 [PubMed - indexed for MEDLINE]  Full Article

STUDY DESIGN: Enzyme-linked immunosorbent assay was used to detect bone morphogenetic proteins (BMPs) 2, 4, and 7 in 9 commercially available ("off the shelf") demineralized bone matrix (DBM) product formulations using 3 different manufacturer's production lots of each DBM formulation. OBJECTIVES: To evaluate and compare the quantity of BMPs among several different DBM formulations (inter-product variability), as well as examine the variability of these proteins in different production lots within the same DBM formulation (intra-product variability). SUMMARY OF BACKGROUND DATA: DBMs are commonly used to augment available bone graft in spinal fusion procedures. Surgeons are presented with an ever-increasing variety of commercially available human DBMs from which to choose. Yet, there is limited information on a specific DBM product's osteoinductive efficacy, potency, and constancy. METHODS: There were protein extracts from each DBM sample separately dialyzed 4 times against distilled water at 4 degrees C for 48 hours. The amount of BMP-2, BMP-4, and BMP-7 was determined using enzyme-linked immunosorbent assay. RESULTS.: The concentrations of detected BMP-2 and BMP-7 were low for all DBM formulations, only nanograms of BMP were extracted from each gram of DBM (20.2-120.6 ng BMP-2/g DBM product; 54.2-226.8 ng BMP-7/g DBM). The variability of BMP concentrations among different lots of the same DBM formulation, intra-product variability, was higher than the variability of concentrations among different DBM formulations, inter-product variability (coefficient of variation range BMP-2 [16.34% to 76.01%], P < 0.01; BMP-7 [3.71% to 82.08%], P < 0.001). BMP-4 was undetectable. CONCLUSIONS: The relative quantities of BMPs in DBMs are low, in the order of 1 x 10(-9) g of BMP/g of DBM. There is higher variability in concentration of BMPs among 3 different lots of the same DBM formulation than among different DBM formulations. This variability questions DBM products' reliability and, possibly, efficacy in providing consistent osteoinduction. PMID: 16721289 [PubMed - indexed for MEDLINE]  Full Article

STUDY DESIGN: An in vitro and in vivo study. OBJECTIVE: To evaluate the ability of fibrin glue to limit diffusion of recombinant human bone morphogenetic protein (rhBMP)-2 and its ability to protect spinal nerves from rhBMP-2 stimulated bone growth. SUMMARY OF BACKGROUND DATA: Studies have shown bone morphogenetic protein (rhBMP-2) stimulated bone growth can encroach on the spinal canal and nerves, causing neural compression. More recently, rhBMP-2 use in the cervical spine has been associated with life-threatening swelling. Fibrin glue has been used as a biologic carrier but has not been evaluated for its ability to limit rhBMP-2. METHODS: In phase 1 of the study, rhBMP-2 soaked absorbable collagen sponges (ACS) were encapsulated in fibrin glue and immediately incubated in physiologic lactated ringers solution at 38 degrees C. Samples of solution were tested for rhBMP-2 concentration. In phase 2 of the study, rats were surgically treated with laminectomy and placement of rhBMP-2/ACS versus laminectomy and placement of fibrin glue before placement of rhBMP-2/ACS. After 8 weeks, animals were euthanized and imaged using micro-computerized tomography. RESULTS: The diffusion study showed a significant limitation in rhBMP-2 diffusion when encapsulated in fibrin glue. The laminectomy study revealed blockage of bone formation by fibrin glue and protection of the spinal canal. CONCLUSIONS: Fibrin glue can limit the diffusion of rhBMP-2, and, thus, it can be used to help protect the spinal canal and nerve roots from rhBMP-2 stimulated bone growth. PMID: 16688032 [PubMed - indexed for MEDLINE]  Full Article

STUDY DESIGN: This is a prospective cohort study examining the results and radiographic characteristics of anterior lumbar interbody fusion (ALIF) using femoral ring allografts (FRAs) and recombinant human bone morphogenetic protein-2 (rhBMP-2). This was compared to a historical control ALIF using FRAs with autologous iliac crest bone graft (ICBG). OBJECTIVE: To determine whether the use of rhBMP-2 can enhance fusion ALIF with stand-alone FRAs. SUMMARY OF BACKGROUND DATA: ALIF is a well-accepted procedure in reconstructive spine surgery. Advances in spinal surgery have produced a multitude of anterior interbody implants. The rhBMP-2 has promoted fusion in patients undergoing ALIF with cages and threaded allograft dowels. The FRA still remains a traditional alternative for anterior support. However, as a stand-alone device, the FRA has fallen into disfavor because of high rates of pseudarthrosis. With the advent of rhBMP-2, the FRA may be more attractive because of its simplicity and remodeling potential. It is important to understand the implications when rhBMP-2 is used with such structural allografts. METHODS: A total of 36 consecutive patients who underwent ALIF with stand-alone FRAs by a single surgeon (E.G.D.) at 1 institute were included. A cohort of 9 consecutive patients who received FRAs filled with rhBMP-2 was followed prospectively. After noticing suboptimal results, the senior author terminated this method of lumbar fusion. A total of 27 prior consecutive patients who received FRAs filled with autogenous ICBG were used for comparison. Analyzing sequential radiographs, flexion-extension radiographs, and computerized tomography with multiplanar reconstructions determined nonunions. Minimum follow-up was 24 months. RESULTS: Pseudarthrosis was identified in 10 of 27 (36%) patients who underwent stand-alone ALIF with FRAs and ICBG. Nonunion rate was higher among patients who received FRAs with rhBMP-2 (i.e., 5 of 9 [56%]). Statistical significance was not established because of the early termination of the treatment group (P > 0.3). Of interest, radiographs and computerized tomography revealed early and aggressive resorption of the FRAs when used with rhBMP-2. This preceded graft fracture and even disintegration, resulting in instability and eventual nonunion. CONCLUSION: The use of rhBMP-2 did not enhance the fusion rate in stand-alone ALIF with FRAs. In fact, the trend was toward a higher nonunion rate with rhBMP-2, although this was not significant with the numbers available. This result appears to be caused by the aggressive resorptive phase of allograft incorporation, which occurs before the osteoinduction phase. PMID: 16648733 [PubMed - indexed for MEDLINE]  Full Article

STUDY DESIGN: Prospective cohort study of 52 patients who had undergone artificial lumbar disc replacement. OBJECTIVES: To evaluate the implantation accuracy of prosthesis positioning, subsequent facet joint changes and prosthesis migration, and the clinical consequences of implant position. SUMMARY OF BACKGROUND DATA: Accuracy of spinal prosthesis implantation has not been evaluated rigorously, especially with a mini-incision approach. It is unknown if the inexact placement of a mobile device in the spine has any biomechanical, radiographic, or clinical repercussions. METHODS: A total of 52 consecutive patients were treated using standard methods of disc implantation with an intervertebral prosthesis. Computed tomography scans were performed within 3 days and again at 6 to 24 months. An independent radiologist analyzed the images for prosthesis position, rotation, migration, and facet changes. Results were compared with clinical outcome, measured by the Visual Analog Scale and Oswestry Disability Index. RESULTS: Deviation of the prosthesis from the center position was under 1.2 mm, and rotation off of midline was under 12 degrees. Follow-up CT scans showed no migration or facet changes. Regression analysis showed no correlation of prosthesis position with clinical outcome. CONCLUSIONS: Current prosthetic disc implantation methods, with minimally invasive access techniques, are relatively accurate. Although there can be deviation of the prosthesis from ideal placement, no repercussions were attributable. PMID: 16622387 [PubMed - indexed for MEDLINE]  Full Article

Epithelial changes overlying dermatofibromas are well recognized. The presence of sebaceous differentiation overlying a dermatofibroma is unusual. We report two patients with sebaceous hyperplasia overlying a dermatofibroma and discuss possible mechanisms for induction of the epithelium and adnexa by the mesenchyme in a dermatofibroma. PMID: 16625080 [PubMed - indexed for MEDLINE]  Full Article

STUDY DESIGN: A retrospective study of patients who underwent 1-3-level kyphoplasty procedures at a single institute. OBJECTIVE: To examine and compare the effects of single and multilevel kyphoplasty procedures on local versus overall sagittal alignment of the spine. SUMMARY OF BACKGROUND DATA: Cement augmentation has been a safe and effective method in the treatment of symptomatic vertebral compression fractures (VCFs). In addition to providing rapid pain relief, balloon tamp kyphoplasty has reduced acute fractures, allowed controlled cement placement under lower pressure, and resulted in improvement of deformity. The restoration of normal overall spinal sagittal alignment in the elderly patient with a VCF and kyphotic deformity has obvious benefits. Although significant correction of local kyphosis (fractured vertebra) has been reported in the literature, to our knowledge, there have been no reports on whether this leads to an improved overall sagittal alignment. METHODS: A total of 65 consecutive patients with symptomatic VCFs who underwent 1-3-level kyphoplasty procedures were included in the study. Preoperative and postoperative radiographs were analyzed to quantify local and overall spinal sagittal alignment correction. Preoperative and postoperative vertebral heights at the fractured levels were also measured and categorized into anterior, middle, or posterior vertebral heights. RESULTS: Measurements revealed that kyphoplasty reduced local kyphotic deformity at the fractured vertebra by an average of 7.3 degrees (63% of preoperative kyphosis). This result did not translate to similar correction in overall sagittal alignment. In fact, angular correction decreased to 2.4 degrees (20% of preoperative kyphosis at fractured level) when measured 1 level above and below. The angular correction further decreased to 1.5 degrees and 1.0 degrees (13% and 8% of preoperative kyphosis at fractured level), respectively, at spans of 2 and 3 levels above and below. Average height gain was highest in the middle of the vertebral body (39% increase) compared to the anterior or posterior edges (19% and 3% increases, respectively). With multilevel kyphoplasty procedures, higher angular gains were seen over more vertebrae compared to the 7.3 degrees for a single-level kyphoplasty: 7.8 degrees over 2 levels and 7.7 degrees over 3 levels for 2 and 3-level kyphoplasty procedures, respectively. Kyphoplasty was able to achieve higher angular reduction in thoracic versus lumbar fractures (8.5 vs. 6.4 degrees, P < 0.01). The angular correction was also better maintained over adjacent segments in the thoracic spine. CONCLUSION: The majority of kyphosis correction by kyphoplasty is limited to the vertebral body treated. The majority of height gained after kyphoplasty occurs in the midbody. Higher correction over longer spans of the spine can be achieved with multilevel kyphoplasty procedures, in proportion to the number of levels addressed. Notwithstanding its well-published clinical efficacy, it is unrealistic to expect a 1 or 2-level kyphoplasty to improve significantly the overall sagittal alignment after VCFs. PMID: 16481954 [PubMed - indexed for MEDLINE]  Full Article

STUDY DESIGN: A retrospective review of 33 consecutive patients treated with posterior fusion and selective nerve root decompression for the treatment of pseudarthrosis following anterior cervical discectomy and fusion. OBJECTIVES: Use standardized outcome measures to evaluate the results of posterior fusion with selective nerve root decompression as a treatment option for symptomatic pseudarthrosis of the cervical spine. SUMMARY OF BACKGROUND DATA: Pseudarthrosis after anterior cervical discectomy and fusion has been recognized as a cause of continued cervical pain and unsatisfactory outcomes. Debate continues as to whether a revision anterior approach or a posterior fusion procedure is the best treatment for symptomatic cervical pseudarthrosis. To our knowledge, standardized outcome measures have not been used to evaluate the results of either surgical treatment option; therefore, it is difficult to evaluate outcomes in these patients, let alone compare surgical treatment options. Data on fusion rates in these two surgical treatment groups suggest a trend of a higher fusion rate with utilization of a posterior revision procedure, but the largest study to date includes the study of only 19 patients treated with a posterior fusion. METHODS: Thirty-three consecutive patients with symptomatic pseudarthrosis following anterior cervical discectomy and fusion were treated with selective nerve root decompression and posterior fusion using iliac crest or local bone graft as well as posterior wiring and/or lateral mass plating. The average follow-up period was 46 months (range, 20-86 months). Patients were assessed using physical examination, flexion-extension lateral radiographs, and standardized outcome measures including the SF-36, Arthritis Impact Measurement Scales 2, and Cervical Spine Outcomes Questionnaire. RESULTS: All 33 patients (100%) demonstrated a solid fusion at their most recent follow-up, and all 33 patients noted significant improvement in their preoperative symptoms. No difference in fusion status was noted between those treated with iliac crest versus patients treated with local bone graft--all had a solid fusion; 72% of the patients were satisfied with the result of their surgery. Cervical Spine Outcomes Questionnaire pain scales demonstrated 52% of patients reported mild or nopain at follow-up, whereas 20% described their pain as "discomforting" and 28% of the patients continued to report moderate to severe pain. CONCLUSIONS: This is the first study to our knowledge to use standardized outcome measures to assess clinical outcome in patients treated with posterior fusion for pseudarthrosis after anterior cervical discectomy and fusion. Patients and surgeons need to understand the potential for success with this revision procedure but also be aware of the relatively high rate of continued moderate to severe pain observed in this patient population even after a solid fusion is achieved. All of the patients in this study fused with a single posterior fusion procedure, further supporting the relatively higher fusion rates observed in the literature using posterior fusion as a treatment for cervical pseudarthrosis. Our results also support the ability of surgeons to use local bone graft without iliac crest in a posterior fusion for cervical pseudarthrosis and therefore avoid the morbidity associated with iliac crest bone graft harvest. PMID: 16261120 [PubMed - indexed for MEDLINE]  Full Article

BACKGROUND: Foot problems are common in patients with Marfan syndrome because of the ligamentous laxity that affects the weightbearing joints most. Such patients frequently are seen by their general practitioners or podiatrists. Educating primary health care providers about a metatarsal index, if it is sufficiently sensitive and specific, may help patients get early and appropriate workup for connective tissue disorders. METHODS: A metatarsal equivalent to the metacarpal index (MCI) in the hand was evaluated as a diagnostic tool for Marfan syndrome (and possibly other connective tissue disorders). Fifty-six patients were studied. Sixteen had a genetic diagnosis of Marfan syndrome. There were 20 controls each for the MCI and the metatarsal index (MTI). Hand and foot radiographs were reviewed. RESULTS: The average MCI in patients with Marfan syndrome was 9.8 compared to 7.6 in the control group (p < 0.0005). The average MTI was 12.7 and 9.8, respectively (p < 0.0005). An MCI value of 8.5 and an MTI value of 10.5 had the best statistical profiles (combination of sensitivity and specificity) in diagnosing Marfan syndrome in our study population. CONCLUSION: The MTI as a screening tool for Marfan syndrome is as effective as, if not more than, the well-recognized MCI. PMID: 16221462 [PubMed - indexed for MEDLINE]  Full Article

Rhodococcus sp. strain YU6 was isolated from soil for the ability to grow on o-xylene as the sole carbon and energy source. Unlike most other o-xylene-degrading bacteria, YU6 is able to grow on p-xylene. Numerous growth substrate range experiments, in addition to the ring-cleavage enzyme assay data, suggest that YU6 initially metabolizes o- and p-xylene by direct aromatic ring oxidation. This leads to the formation of dimethylcatechols, which was further degraded largely through meta-cleavage pathway. The gene encoding meta-cleavage dioxygenase enzyme was PCR cloned from genomic YU6 DNA using previously known gene sequence data from the o-xylene-degrading Rhodococcus sp. strain DK17. Subsequent sequencing of the 918-bp PCR product revealed a 98% identity to the gene, encoding methylcatechol 2,3-dioxygenase from DK17. PFGE analysis followed by Southern hybridization with the catechol 2,3-dioxygenase gene demonstrated that the gene is located on an approximately 560-kb megaplasmid, designated pJYJ1. PMID: 16145546 [PubMed - indexed for MEDLINE]  Full Article

The much-awaited clinical use of lumbar artificial discs has begun in the United States. The United States Investigational Device Exemption (US IDE) clinical trial of the ProDisc-II prosthetic disc (Synthes, Paoli, PA) was recently completed, with all indications that it meets or surpasses the test of equivalence against fusion controls. This is a review of the clinical performance of the ProDisc-II artificial disc and includes an interim report from the US IDE trial at one site. PMID: 15950690 [PubMed - indexed for MEDLINE]  Full Article

BACKGROUND CONTEXT: With the number of anterior lumbar procedures expected to increase significantly over the next few years, it is important for spine surgeons to have a good understanding about the incidence of vascular complications during these operations. PURPOSE: To determine the incidence of vascular injury in 1,315 consecutive cases undergoing anterior lumbar surgery at various levels from L2 to S1. STUDY DESIGN/SETTING: Patients undergoing anterior lumbar surgery were studied. PATIENT SAMPLE: A total of 1,310 consecutive patients undergoing 1,315 anterior lumbar procedures between August 1997 and December 2002 were included in the study. OUTCOME MEASURES: All patients were evaluated for incidence of vascular injury during and immediately after surgery. METHOD: A concurrent database was maintained on all these cases. All the patients had distal pulse evaluation preoperatively. Patients with venous injuries were further analyzed to determine location and extent of injury, amount of blood loss, completion of the procedure and postoperative sequelae. Patients with pulse deficits or evidence of ischemia during or immediately after surgery were further analyzed in particular in relation to demographic, preoperative variables and management. RESULTS: Six patients were identified as having left iliac artery thrombosis (0.45%), and 19 had major vein lacerations (1.4%). CONCLUSION: This study shows that the incidence of vascular injury is relatively low (25 in 1,315 or 1.9%). Because only five of these patients experienced significant sequelae from the approach, it appears that anterior lumbar surgery is quite safe, although it must be carried out with utmost respect for the vessels to avoid possible catastrophic outcomes. PMID: 15246301 [PubMed - indexed for MEDLINE]  Full Article

STUDY DESIGN: The accuracy and interobserver agreement of fine detail radiography and computed tomography (CT) determination of spinal fusion were evaluated in an established animal spine fusion model. OBJECTIVE: To determine the accuracy and interobserver agreement of radiographic determinations of spinal fusion in rabbit posterolateral spine fusion. SUMMARY OF BACKGROUND DATA: The rabbit posterolateral intertransverse process spine fusion model is an established animal model for evaluating bone graft alternatives for spinal fusion. However, little is known regarding the accuracy and interobserver agreement of radiographic determinations of spondylodesis in this model. METHODS: Forty-two New Zealand White rabbits underwent posterolateral spinal fusion. The animals were killed at 9 weeks and the lumbar spine harvested. Manual manipulation, fine detail radiography, and CT images were used to assess spinal fusion. RESULTS: Using manual palpation testing as the standard by which to assess fusion, there was high sensitivity and negative predictive value for both radiographic methods. Positive predictive value, however, was poor (26% fine detail radiography, 61% CT scan). CT correlated better with manual palpation testing when compared with fine detail radiographs. There was substantial interobserver agreement of successful fusion using CT scan imaging (kappa = 0.63) and moderate interobserver agreement radiographs (kappa = 0.52). CONCLUSIONS: Both radiographic techniques used in the study recorded high sensitivity and negative predictive value. However, positive predictive value was poor, especially with fine detail radiographs. Nevertheless, CT with reformatted images did appear to be superior to fine detail radiographs in accurately identifying nonunions in this animal model. PMID: 15187630 [PubMed - indexed for MEDLINE]  Full Article

STUDY DESIGN: Retrospective study with independent evaluation of patient outcomes approximately 1 year post-intradiscal electrothermal therapy (IDET). OBJECTIVE.: To assess functional status, symptoms, and subsequent treatments of patients treated with IDET. SUMMARY OF BACKGROUND DATA: IDET was introduced as a procedure for discogenic pain. Several studies reported improvement in >70% of patients. METHODS: Seventeen physicians referred 60 patients. Each patient had a positive discogram and had been treated with IDET. Patients were contacted approximately 1 year post-IDET, answered a telephone interview, and completed a self-administered questionnaire. Overall patient satisfaction, pain, functional and work status, analgesic usage, and subsequent treatments were noted. Kaplan-Meier survival curve was generated to predict the percentage that would undergo lumbar surgery after IDET. RESULTS: Average age was 40 years (range 25-64 years) with 66% males and 34% females. Of the 44 patients who responded, 6 patients had a lumbar surgery within 1 year. Their outcomes were excluded from descriptive analysis; 97% continued to have back pain, 11 (29%) reported more pain post versus pre-IDET, 15 (39%) had less pain, and 11 (29%) reported no change; 11 (29%) reported using more pain medication post-IDET, 10 (26%) used the same, 12 (32%) used less, and 5 (13%) used none; 19 (50%) were dissatisfied with IDET, 14 (37%) were satisfied, and 5 (13%) were undecided; 20 (53%) would have the procedure again, 12 (31%) would not, and 6 (16%) were unsure. Most patients wore a brace >6 hours/day after surgery (duration 1-15 months). Sixteen (42%) were employed full-time pre-IDET and 11 (29%) were employed full-time post-IDET. CONCLUSION: At 1-year post-IDET, half of patients were dissatisfied with their outcome. The percentage of patients on disability remained constant. The estimated proportion of patients undergoing fusion was predicted to be 15% at 1 year and 30% at 2 years. PMID: 15087797 [PubMed - indexed for MEDLINE]  Full Article

STUDY DESIGN: A retrospective outcomes study. OBJECTIVES: To examine the outcome following adjacent two-level lumbar discectomy using both surgeon-based evaluation criteria and validated patient-based quality of life instrument (SF-36). SUMMARY OF BACKGROUND DATA: Lumbar discectomies have documented success rates between 49% and 98% for single-level procedures. However, no prior study has specifically examined the outcome following adjacent two-level lumbar discectomy in a large series of patients. METHODS: This study analyzed 55 patients with a minimum 2-year follow-up. All patients underwent adjacent two-level lumbar discectomy for radicular pain attributable to nerve root impingement at the corresponding levels. The patients were divided into two diagnostic groups based on their preoperative radiographic studies. Patients with two-level adjacent posterolateral lumbar disc herniations without concomitant osseous degenerative changes at the same levels constituted Group 1 (22 patients). Patients with associated osseous degenerative changes at the same levels made up Group 2 (33 patients). The patients' clinical outcome was assessed using the MacNab classification and SF-36 questionnaire. RESULTS: The average duration of follow-up was 41 months (range 24-96 months). The group consisted of 35 males and 20 females with average age of 49 years (range 19-82 years). Excellent results were observed in 49%, good in 20%, fair in 15%, and poor in 16%. However, patients in Group 1 have 86% excellent/good results, whereas patients in Group 2 have 57% excellent/good results. Overall, 15% of the patients required reoperation and subsequent spinal fusion. Analysis of the SF-36 scores revealed significant differences based on patient's diagnostic grouping as well. Patients in Group 1 have physical and mental summary scores comparable with age- and sex-adjusted population norms and significantly higher than those in Group 2 (P < 0.01). CONCLUSIONS: Two-level discectomy is an effective treatment with clinical outcome comparable with single-level discectomy. Patients with posterolateral disc herniations and definitive radiculopathy without osseous degenerative changes at the same levels have better clinical outcome and quality of life scores compared with those patients having concomitant degenerative arthritis at the same levels. Patients having two-level discectomy may be at increased risk of requiring subsequent lumbar fusion compared with those with single-level discectomy. PMID: 14722421 [PubMed - indexed for MEDLINE] Full Article

To determine the incidence of left iliac artery thrombosis (LIAT), a prospective database was maintained on 1315 patients undergoing anterior lumbar surgery (ALS) between August 1997 and December 2002. All had distal pulse evaluation preoperatively. In the last 629 cases pulse oxymetry was used to monitor the distal circulation during and after surgery. Patients with pulse deficits or evidence of ischemia after surgery were further analyzed. Six patients were identified with LIAT (0.45%). Five were females and one was male, with ages ranging from 35 to 56 years. All had exposure at the L4-5. Five were diagnosed at surgery and one in the recovery room after posterior surgery. All except one had strong, palpable preoperative pulses. Pulse oxymetry confirmed the diagnosis in two patients, in whom it was not clinically evident. Four had successful thrombectomy; one had a femoro-femoral bypass and one had an axillo-femoral bypass. Two developed compartment syndrome. None had calcifications on preoperative X-rays. LIAT is an uncommon complication of ALS. Early identification and management can avoid long-term complications. Pulse oxymetry helps in its timely identification. Patients undergoing exposure at L4-5 and females are at greater risk. PMID: 14712382 [PubMed - indexed for MEDLINE]  Full Article

Few data are available to evaluate approach-related differences in perioperative complications with lumbar interbody fusion devices. Complications occurring in the intraoperative and immediate postoperative period were identified and categorized for 31 consecutive posterior lumbar interbody fusions (PLIFs) and 88 consecutive anterior lumbar interbody fusions (ALIFs). In this study, all lumbar interbody fusions were conducted with threaded cylindrical devices as stand-alone internal fixation devices. Multivariate analysis was used to account for potential covariates and identify factors associated with an increased complication risk. Twenty-two percent of the patients had a perioperative complication. The relative risk of having a perioperative complication was 4.75 times higher for the PLIF group. All intraoperative complications occurred in the PLIF group. The relative risk of having a major postoperative complication was 6.8 times higher in the PLIF group than the ALIF group. Anterior approached patients tended to have visceral (ileus, 6%) and vascular (deep venous thrombosis, 2%) complications. In the posterior group, complications were neurologic and dura related (pseudomeningocele, 16%; epidural hematoma, 3%) and occurred most frequently in patients that had had previous posterior lumbar surgery (31% with major complication). PMID: 14657745 [PubMed - indexed for MEDLINE]  Full Article

The objective of this study was to compare the pharmacokinetics (PK), pharmacodynamics (PD), and safety of inhaled insulin delivered by the AERx iDMS in young and elderly patients with type 2 diabetes. Twenty-seven young (18-45 years, inclusive) and 28 elderly (>/= 65 years) type 2 diabetic patients were enrolled in this study. A single inhalation of 1.57 mg (45 IU, effect comparable to 6 s.c. units) of regular human insulin was administered to each patient on each of 2 dosing days, and blood samples were drawn up to 360 minutes postdosing to generate the PK/PD curves. AUC(0-360 min) and Cmax values of inhaled insulin were comparable between young and elderly subjects (p = 0.476 for AUC(0-360 min) and p = 0.414 for Cmax). However, the elderly group had significantly less glucose reduction, as indicated by plasma glucose AOC(0-360) (area over the curve) values (p = 0.011). The intrasubject variability of inhaled insulin using the AERx iDMS was similar for young and elderly subjects and was similar to what has previously been reported for soluble insulin administered subcutaneously. Inhaled insulin was well tolerated in these patients, and no changes in pulmonary function tests were observed. A single inhalation of insulin using the AERx iDMS demonstrated comparable insulin PK profiles between the elderly and young type 2 patients but less glucose reduction in the elderly. Based on these results, elderly diabetic patients may need to inhale more insulin than young patients to achieve similar glycemic control. Long-term clinical trials using the AERx device will be useful to study age-related differences. PMID: 14551177 [PubMed - indexed for MEDLINE]  Full Article

STUDY DESIGN: Posterolateral spinal fusion with allogeneic demineralized bone graft-hyaluronan putty in addition to autogenous iliac crest bone graft in a rabbit model. OBJECTIVES: To determine the potential efficacy of demineralized bone graft-hyaluronan putty as a bone graft enhancer. SUMMARY OF BACKGROUND DATA: Autograft bone is the material of choice for posterolateral lumbar intertransverse process fusion. Bone graft alternatives such as demineralized bone matrices that can be used as graft extenders, enhancers, or substitutes continue to be developed. METHODS: One hundred New Zealand white rabbits underwent bilateral posterolateral spinal fusion with autogenous iliac crest bone graft or bone graft with allogeneic rabbit demineralized bone graft-hyaluronan putty. The rabbits were killed 9 weeks later, and the lumbar spines were removed. Manual manipulation and fine detail radiography were used to assess spinal fusion, and computed tomographic images were used to quantify the volume of the fusion mass. RESULTS: In comparison with autograft bone alone, the fusion rates were greater when demineralized bone graft-hyaluronan putty was used as an adjunct to autogenous bone. Furthermore, the radiographic fusion rate was greater when demineralized bone graft-hyaluronan putty was used in a 2:1 ratio to autograft bone in comparison with a 1:1 ratio (P = 0.001). The addition of demineralized bone graft-hyaluronan putty to autograft bone was found to increase mineralized bone volume in a ratio-dependent manner (P < 0.05). CONCLUSIONS: Allogeneic demineralized bone matrix-hyaluronan putty enhances rabbit posterolateral spine fusion when used as an adjunct to autogenous bone graft. This new formulation of demineralized bone matrix may facilitate greater bone formation and successful fusion. PMID: 14595160 [PubMed - indexed for MEDLINE]  Full Article

STUDY DESIGN: Multicenter prospective randomized study of artificial disc replacement (ProDisc) versus circumferential fusion (standard of care) for one- and two-level degenerative disc disease. This is an interim analysis on patients seen at the Spine Institute Saint John's Health Center, Santa Monica, California. OBJECTIVES: To evaluate early pain and functional outcomes of patients treated with disc replacement or fusion and to assess the capacity of this intervertebral disc replacement for preserving motion in the lumbar spine. SUMMARY OF BACKGROUND DATA: Disc replacement is intended to reduce pain via removal of the diseased disc while restoring physiologic motion and height at the affected level. The long-term physiologic advantage of disc replacement to fusion is that preservation of motion may prevent additional degeneration at adjacent levels. METHODS: Patients meeting inclusion criteria were consented for study. Randomization was performed using a 2 to 1 ratio of disc replacement procedure to a fusion procedure. Patients rated their pain on the Visual Analogue Scale and completed the Oswestry Disability Index questionnaire. Radiographs were taken. Assessments were made before surgery and after surgery at 6 weeks, 3 months, 6 months, and 1 year (ongoing). Changes from preoperative pain, disability, or motion were separately evaluated as a function of treatment using repeated measures mixed design analysis of variance. RESULTS: This analysis includes data up to 6 months from the first 53 randomized patients. There were 35 patients who underwent disc replacements, and 18 patients had fusion procedures. Disc replacement patients had a significant reduction in pain and disability at earlier evaluations. By 6 months, the relative improvement on both the Visual Analogue Scale and Oswestry (both, P < 0.05) were similar for disc replacement and fusion patients. Greater motion was found at L4-L5 for disc replacement patients (P < 0.05) than fusion patients. A similar trend was noted at L5-S1 (P was not significant). CONCLUSIONS: Disc replacement patients reported significantly less pain (Visual Analogue Scale) and disability (Oswestry) in the early period following surgery compared to fusion patients. This difference disappeared by 6 months. When compared to fusion, the disc replacement allowed preservation of motion at L4-L5 with a similar trend at L5-S1. PMID: 14560188 [PubMed - indexed for MEDLINE]  Full Article

Although the operating microscope has been used for spine surgery for more than 20 years, its use is still not widely accepted by orthopaedic spine surgeons. Nevertheless, surgeons who have used the operating microscope are well aware of its many advantages in performing spine surgery. Most notably, the superior visualization it provides allows for faster, safer, and more extensive decompressions. The reluctance of many surgeons to use the operating microscope often has to do with trepidation regarding new technology. The use of the operating microscope when performing anterior and posterior cervical spine surgery makes these procedures easier to carry out and decreases the risk of complications during decompression of the spinal cord.  

In hopes of improving outcomes for patients with discogenic pain, less invasive techniques that reduce trauma and shorten the recovery period have been developed. This article attempts to present a comprehensive description of minimally invasive techniques, specifically heat treatments, for lumbar disc disease. The goal is to inform and educate the reader on the various thermal therapies available for lumbar disc disease by evaluating the scientific data in an objective manner. PMID: 12914265 [PubMed - indexed for MEDLINE]  Full Article

STUDY DESIGN: A retrospective study was used to review fellowship applications over 3 years. OBJECTIVES: To assess the prevalence of research misrepresentation in orthopedic fellowship applications, and to compare such activity between subspecialties (e.g., spine, sports, hand). SUMMARY OF BACKGROUND DATA: Competition for orthopedic surgery fellowships is intense. The applicant pool includes orthopedic, plastic, and general surgeons, as well as neurosurgeons. Residency and fellowship training programs in other disciplines have documented shocking levels of misrepresentation in the curriculum vitae of prospective applicants. However, no study has looked at orthopedic residents applying for subspecialty fellowship programs. METHODS: A retrospective analysis investigated 280 applications for fellowship positions in the department of orthopedic surgery at the authors' academic institution from 1996 to 1998 inclusively. To allow for press and publication delays, a minimum 24-month follow-up period was instituted. The listings of applicants' research publications were analyzed for evidence of misrepresentation through an exhaustive literature search. Only the most obvious confirmable discrepancies were labeled as misrepresentations. The results then were compared with those found in studies conducted in other fields: gastroenterology fellowship, emergency medicine residency, pediatric residency, dermatology residency, orthopedic residency, and medical faculty applications. RESULTS: Among 280 (54%) applicants for orthopedic surgery fellowships, 151 claimed journal publications. It was found that 16 (10.6%) of these 151 applicants had misrepresented their citations. This rate was highest in spine fellowship applicants (20%). However, considering the numbers available, this was not significantly different among the various subspecialty fellowship applicants (P > 0.1). In addition, various demographic data did not correlate with the rate of misrepresentation (P > 0.1). These results are comparable with those reported in other medical fields (P > 0.1). CONCLUSIONS: Misrepresentation occurs in orthopedic fellowship applications at a rate comparable with that observed in other fields. This rate is not different among the various subspecialties in orthopedics. Policies that may lessen the incidence of falsification on curriculum vitae should be instituted in an attempt to curb such activity. PMID: 12671346 [PubMed - indexed for MEDLINE]  Full Article

Study Design. A retrospective study was used to review fellowship applications over 3 years. Objectives. To assess the prevalence of research misrepresentation in orthopedic fellowship applications, and to compare such activity between subspecialties (e.g. spine, sports, hand). Summary of Background Data. Competition for orthopedic surgery fellowships is intense. The applicant pool includes orthopedic, plastic, and general surgeons, as well as neurosurgeons. Residency and fellowship training programs in other disciplines have documented shocking levels of misrepresentation in the curriculum vitae of prospective applicants. However, no study has looked at orthopedic residents applying for subspecialty fellowship programs. Methods. A retrospective analysis investigated 280 applications for fellowship positions in the department of orthopedic surgery at the authors' academic institution from 1996 to 1998 inclusively. To allow for press and publication delays, a minimum 24-month follow-up period was instituted. The listings of applicants' research publications were analyzed for evidence of misrepresentation through an exhaustive literature search. Only the most obvious confirmable discrepancies were labeled as misrepresentations. The results then were compared with those found in studies conducted in other fields: gastroenterology fellowship, emergency medicine residency, pediatric residency, dermatology residency, orthopedic residency, and medical faculty applications. Results. Among 280 (54%) applicants for orthopedic surgery candidates, 151 claimed journal publications. It was found that 16 (10.6%) of these 151 applicants had misrepresented their citations. This rate was highest in spine fellowship applicants (20%). However, considering the numbers available, this was not significantly different among the various subspecialty fellowship applicants (P>0.1). In addition, various demographic data did not correlate with the rate of misrepresentation (P>0.1). These results are comparable with those reported in other medical fields (P>0.1). Conclusions. Misrepresentation occurs in orthopedic fellowship applications at a rate comparable with that observed in other fields. This rate is not different among the various subspecialties in orthopedics. Policies that may lessen the incidence of falsification on curriculum vitae should be instituted in an attempt to curb such activity. PMID: 15164751 [PubMed - indexed for MEDLINE]  Full Article

This study is a retrospective review of 122 patients who underwent single-level lumbar spine fusion. The objectives were to directly compare perioperative morbidity and early results of single-level anterior interbody posterolateral intertransverse process lumbar spine fusion and to provide objective findings that may be useful in selecting surgical method. Lumbar spinal fusion is a well-recognized surgical treatment of intractable low back pain resulting from DDD or spondylolisthesis. Assessments of techniques, results, and outcomes have been published, but detailed head-to-head comparisons of anterior posterior approaches with objective operative and postoperative data are not available in the literature. A retrospective review of 122 patients who underwent either an anterior interbody or posterolateral intertransverse process (average follow-up 22 and 26 months, respectively) single-level instrumented lumbar spinal fusion was performed. Surgical, perioperative, and follow-up data were obtained directly from medical records. The findings compared included estimated blood loss, need for blood transfusion, number of units transfused, operative time, number of days in hospital, need for transitional facility care, complications, need for further surgery, radiographic fusion, and clinical results. There was significantly less blood loss, need for transfusion, amount of blood transfused, operative time, and hospital stay for patients with anterior fusion procedures (p < 0.01). There was no significant difference in need for transitional facility care, complication rates, and given follow-up period in radiographic fusion rate and clinical outcome. Clinical results were significantly worse for those undergoing revision primary fusion (p < 0.01). The anterior approach to single-level lumbar fusion is associated with less morbidity than the posterolateral approach. This may in turn affect surgical outcome and hospital cost. However, both approaches to single-level lumbar fusion produce similar early fusion rates and clinical results. Revision fusions had poor early results regardless of approach. PMID: 12394658 [PubMed - indexed for MEDLINE]  Full Article

STUDY DESIGN: Patients with low back pain were asked to recall the pain and impaired functioning that they reported 5-10 years previously as part of the National Low Back Pain prospective follow-up study. In 1998, patients completed an additional follow-up. OBJECTIVES: To compare outcomes using patient-recalled data and prospectively collected data from patients with low back pain and to identify simple, symptom-specific questions that yield reliable responses over an extended period of time. SUMMARY OF BACKGROUND DATA: Outcome assessment based on patient recall may be influenced by a patient's age, gender, reporting tendency, and current health status. The impact of data collected retrospectively on outcome analyses in spinal patients has not been addressed. METHODS: Patients enrolled in the National Low Back Pain study from 1986 to 1991 completed a self-administered questionnaire at their initial visit. A sample was interviewed by telephone in 1996 and asked to recall pain characteristics and impaired functioning reported at initial examination. A 10-year follow-up (1998) on current health status was conducted by mail. The 1998 follow-up response was separately compared with recalled and initial responses, such that two patient outcome status values were calculated for each question. Agreement was evaluated using Cohen's kappa. RESULTS: The follow-up evaluation was completed by 144 patients, with a mean interval of 9.4 years. The overall simple kappa was 0.37, indicating "fair" agreement between outcomes based on initial and recalled accounts of pain. Questions on location of pain had kappa values of 0.12-0.58, radicular symptoms 0.28-0.48, and severity of pain 0.11-0.30. CONCLUSIONS: "Fair" to "moderate" agreement was found between outcomes determined by recalled versus initial reports. Accuracy was greatest for queries on frequency, location of pain, and activities affecting pain. Discrepancies were noted for queries on severity of pain, with error bias toward less pain when using the recalled data. Careful selection of questions may yield more accurate outcome measures. PMID: 11979175 [PubMed - indexed for MEDLINE]  Full Article

P11, a member of the S100 family of calcium-binding proteins, has been shown to interact with BAD (Bcl-xL/Bcl-2-associated death promoter) in the yeast two-hybrid protein-protein interaction assay. Because overexpression of P11 dampens the proapoptotic activity of BAD in transfected cells, we tested the possibility that the expression of this antiapoptotic protein may be regulated by gonadotropins and other survival factors in the ovary. Northern blot analysis of ovaries obtained from prepubertal rats revealed an increased expression of P11 messenger RNA (mRNA) during prepubertal development in the theca cells of preantral and early antral follicles. Treatment of immature rats with PMSG did not affect P11 expression, whereas treatment of PMSG-primed rats with an ovulatory dose of human (h)CG stimulated ovarian P11 mRNA within 6-9 h in the granulosa cells of preovulatory follicles. Treatment of cultured preovulatory follicles in vitro with LH further confirmed the time-dependent stimulation of P11 by gonadotropins. In addition, treatment of cultured preovulatory follicles with MDL-12,330A, an inhibitor of adenylate cyclase, inhibited LH-stimulated P11 mRNA, whereas treatment with forskolin, an adenylate cyclase activator, but not the protein kinase C activator, 2-O-tetradecanol-phorbal-13-acetate, mimicked the LH action, suggesting the role of adenylate cyclase activation in P11 expression. Treatment with other follicle survival factors, including the epidermal growth factor, the basic fibroblast growth factor, and interleukin-1beta, could also stimulate P11 expression in cultured preovulatory follicles. These results demonstrate the expression of P11 mRNA in theca cells of different-sized follicles and in granulosa cells of preovulatory follicles following gonadotropin stimulation, and suggest that P11 may mediate, at least partially, the survival action of gonadotropins during the ovulatory process. PMID: 11356677 [PubMed - indexed for MEDLINE]  Full Article

A single corpectomy and strut grafting has been proposed as an alternative to performing two-level adjacent discectomies with multiple grafts to produce superior fusion rates. The purpose of this study was to compare the clinical and radiographic success of two-level discectomy and fusion with anterior cervical plate fixation compared with a single-level corpectomy. Fifty-two patients were treated with either a two-level adjacent anterior cervical discectomy and fusion with cervical plating, or by a single-level corpectomy and plate. Thirty-two patients had two-level discectomies, whereas 20 had a single corpectomy and a strut graft (average follow-up was 3.6 years). One patient had a pseudarthrosis from a single-level corpectomy and required subsequent surgery to obtain an osseous union. The fusion rates between the two groups was not statistically significant (p = 0.385). The clinical results of the surgeries were similar between the groups based on Odom's criteria. The addition of cervical plates to either two-level discectomies or single-level corpectomies yielded similar fusion and complication rates. PMID: 11389372 [PubMed - indexed for MEDLINE]  Full Article

STUDY DESIGN: A retrospective review of all patients surgically treated by a single surgeon with a three-level anterior cervical discectomy and fusion with and without anterior plate fixation. OBJECTIVES: To compare the clinical and radiographic success of anterior three-level discectomy and fusion performed with and without anterior cervical plate fixation. SUMMARY OF BACKGROUND DATA: Previous studies of multilevel cervical discectomies and fusions have shown fusion rates to decrease as the number of surgical levels increases. Anterior cervical plate stabilization can provide more stability and may increase fusion rates for multilevel fusions. METHODS: Over a 7-year period, 59 patients were treated surgically with a three-level anterior cervical discectomy and fusion by the senior author. Forty patients had cervical plates, whereas 19 had fusions with no plates. These patients were observed for an average of 3.2 years. Clinical and radiographic follow-up data were obtained. RESULTS: Of the 59 patients, 14 had a pseudarthrosis (7 in each group). The pseudarthrosis rates were 18% (7 of 40) for patients with plating and 37% (7 of 19) for patients with no plating. Although the nonunion rate for unplated fusions was double that of plated fusions, this difference was not statistically significant. There was no statistically significant correlation between pseudarthrosis and gender, age, level of surgery, history of tobacco use, or previous anterior surgery. The fusion rates were improved with the use of a cervical plate. Inferior clinical results were demonstrated in patients with a pseudarthrosis, regardless of the use of a cervical plate. CONCLUSIONS: The addition of plate fixation for three-level anterior cervical discectomy and fusion is a safe procedure and does not result in higher complication rates. In this study, the pseudarthrosis rate was lower for patients with a cervical plate. However, this difference was not statistically significant. Patients treated with cervical plating had overall better results when compared with those of patients treated without cervical plates. Although the use of cervical plates decreased the pseudarthrosis rate, a three-level procedure is still associated with a high nonunion rate, and other strategies to increase fusion rates should be explored. PMID: 11246376 [PubMed - indexed for MEDLINE]  Full Article

STUDY DESIGN: This report describes four cases of symptomatic cerebral spinal fluid leak after lumbar microdiscectomy where ADCON-L was used. OBJECTIVES: To report that ADCON-L may exacerbate cerebral spinal fluid leak from unrecognized, small dural tears after lumbar discectomy. SUMMARY OF BACKGROUND DATA: ADCON-L is a porcine-derived polyglycan that is used with increasing frequency in spinal surgery. It is advocated to reduce postoperative peridural fibrosis and adhesions. METHODS: Four cases of symptomatic cerebral spinal fluid leak after lumbar microdiscectomy were identified. Information on these patients was obtained by chart review. RESULTS: Three patients had small, inadvertent durotomies that were not appreciated at surgery even with the aid of a microscope. The dural violation in the fourth patient occurred at the previous epidural steroid injection site located on the contralateral side of the laminotomy. CONCLUSION: ADCON-L may inhibit dural healing and exacerbate cerebral spinal fluid leak from microscopic durotomies not recognized at the time of surgery. PMID: 11148655 [PubMed -