Thomas E. Mroz

Musculoskeletal allograft risks and recalls in the United States.

&NA; There have been several improvements to the US tissue banking industry over the past decade. Tissue banks had limited active government regulation until 1993, at which time the US Food and Drug Administration began regulatory oversight because of reports of disease transmission from allograft tissues. Reports in recent years of disease transmission associated with the use of allografts have further raised concerns about the safety of such implants. A retrospective review of allograft recall data was performed to analyze allograft recall by tissue type, reason, and year during the period from January 1994 to June 30, 2007. During the study period, more than 96.5% of all allograft tissues recalled were musculoskeletal. The reasons underlying recent musculoskeletal tissue recalls include insufficient or improper donor evaluation, contamination, recipient infection, and positive serologic tests. Infectious disease transmission following allograft implantation may occur if potential donors are not adequately evaluated or screened serologically during the prerecovery phase and if the implant is not sterilized before implantation.

Radiation Exposure to the Surgeon and the Patient During Kyphoplasty

Study Design Prospective study of patients who underwent single or multilevel kyphoplasty for vertebral fractures. Objective To quantify the radiation exposure to the surgeon and to the patient during kyphoplasty, and also to provide a procedural algorithm that effectively minimizes the radiation exposure to the surgeon during any fluoroscopic-guided procedure. Summary of Background Data Spine surgeons who perform minimally invasive procedures often employ fluoroscopy for intraoperative navigation. Methods Twenty-seven patients were enrolled. Two fluoroscopes (1 anterior/posterior and 1 lateral) were used for localization, navigation, and monitoring cement flow. All surgeons wore thyroid shields and lead aprons. The dose of radiation exposure was measured by dosimeter badges. One badge was attached to each patient. The surgeons wore 3 badges: under the thyroid shield (protected), under the lead apron over the left chest (protected), and outside the lead apron over the left chest (unprotected). A thermoluminescent ring dosimeter was worn on the right hand for 18 cases, and on the left hand for 9 cases. Results The exposure time was 5.7±2.0 minutes/vertebra for a single level (n=10), 3.9±0.8 minutes/vertebra for a 2 level (n=9), 2.9±1.2 minutes/vertebra for a 3 level kypholasty (n=8). The exposure time of single level kyphoplasy was significantly different from that of multilevel kyphoplasy (2 level, P=0.040; 3 level, P=0.002). Surgeon exposure as measured by the protected dosimeter was less than the minimum reportable dose (<0.010 mSv). Exposure as measured by the unprotected dosimeter, which is equivalent to deep whole body exposure was 0.248±0.170 mSv/vertebra. The eye exposure was 0.271±0.200 mSv/vertebra, and the shallow exposure (hand/skin) was 0.273±0.200 mSv/vertebra. The hand exposure was 1.744±1.173 mSv/vertebra. Conclusions Without eye or hand protection, the total radiation exposure dose to these areas would exceed the occupational exposure limit after 300 cases per year. Surgeons should wear lead lined glasses and keep their hands out of the radiation beam.

Radiation Exposure to the Surgeon During Open Lumbar Microdiscectomy and Minimally Invasive Microdiscectomy : A Prospective, Controlled Trial

Study Design. This is a prospective in vivo study comparing radiation exposure to the surgeon during 10 minimally invasive lumbar microdiscectomy cases with 10 traditional open discectomy cases as a control. Objective. Radiation exposure to the eye, chest, and hand of the operating surgeon during minimally invasive surgery (MIS) and open lumbar microdiscectomy were measured. The Occupational Exposure Guidelines were used to calculate the allowable number of cases per year from the mean values at each of the 3 sites. Summary of Background Data. Fluoroscopy is a source of ionizing radiation and as such, is a potential health hazard with continued exposure during surgery. Presently, radiation exposure to the surgeon during MIS lumbar microdiscectomy is unknown. Methods. Radiation exposure to the surgeon (millirads [mR]) per case was measured by digital dosimeters placed at the level of the thyroid/eye, chest, and dominant forearm. Other data collected included operative side and level, side of the surgeon, side of the x-ray source, total fluoroscopy time, and energy output. Results. The average radiation exposure to the surgeon during open cases was thyroid/eye 0.16 ± 0.22 mR, chest 0.21 ± 0.23 mR, and hand 0.20 ± 0.14 mR. During minimally invasive cases exposure to the thyroid/eye was 1.72 ± 1.52 mR, the chest was 3.08 ± 2.93 mR, and the hand was 4.45 ± 3.75 mR. The difference between thyroid/ eye, chest, and hand exposure during open and minimally invasive cases was statistically significant (P = 0.010, P = 0.013, and P = 0.006, respectively). Surgeons standing in an adjacent substerile room during open cases were exposed to 0.2 mR per case. Conclusion. MIS lumbar microdiscectomy cases expose the surgeon to significantly more radiation than open microdiscectomy. One would need to perform 1623 MIS microdiscectomies to exceed the exposure limit for whole-body radiation, 8720 cases for the lens of the eye, and 11,235 cases for the hand. Standing in a substerile room during x-ray localization in open cases is not fully protective.

Radiation exposure to the surgeon during percutaneous pedicle screw placement.

Study Design In-vitro radiation exposure study. Objective To determine the radiation exposure to the eyes, extremities, and deep tissue during percutaneous pedicle screw placement. Summary of Background Data Image-guided minimally invasive spinal surgery is typically performed with the use of fluoroscopy, exposing the surgeon and patient to ionizing radiation. The radiation dose to the surgeon has not been reported and risk to the surgeon performing this procedure over the long term is uncertain. Methods Percutaneous pedicle screws were placed in a cadaveric specimen from L2-S1 bilaterally using a cannulated pedicle screw system. Two fluoroscopes were used in the anteroposterior and lateral planes. The surgeon wore a thermolucent dosimeter ring on the right hand and badge over the left chest beneath the lead apron. Complete surgical time was recorded and a computed tomography scan was performed to assess screw placement. Radiation exposure was measured for total time of fluoroscopy use; average exposure per screw, surgical level, and dose to the eyes was calculated. This data was used to define the safety of percutaneous pedicle screw placement. Results Total fluoroscope time for placement of 10 percutaneous pedicle screws was 4 minutes 56 seconds (29 s per screw). The protected dosimeter recorded less than the reportable dose. The ring dosimeter recorded 103 mREM, or 10.3 mREM per screw placed. All screws were within the bone confines with acceptable trajectory. Exposure to the eyes was 2.35 mREM per screw. Conclusions On the basis of this data, percutaneous pedicle screw placement seems to be safe. A surgeon would exceed occupational exposure limit for the eyes and extremities by placing 4854 and 6396 screws percutaneously, respectively. Lead protected against radiation exposure during screw placement. The “hands-off” technique used in this study is recommended to minimize radiation exposure. Lead aprons, thyroid shields, and leaded glasses are recommended for this procedure.

A prospective analysis of prognostic factors in patients with spinal metastases: use of the revised Tokuhashi score.

Study Design. Prospective observational cohort study. Objective. To define the utility of the revised Tokuhashi score in relation to predicting survival in patients with spinal metastases regardless of the treatment pathway. Summary of Background Data. The revised Tokuhashi score has been used for the prediction of survival. In this scoring system, however, all the patients were sourced by orthopedic surgeons, and asymptomatic patients were excluded. That might present a significant source of patient selection bias. The treatment plan was also affected by the predicted survival in their system. Methods. All patients within 2 years of diagnosis of spinal metastases, whether symptomatic were recruited. Minimum 1-year follow-up was required. During the study period, a total of 85 patients were analyzed including 44 patients who died within 1 year. The relation between the revised Tokuhashi score and survival were analyzed using the Cox proportional hazard model and Spearmans rank correlation coefficient. Results. The mean age was 60.3 years (range: 35–84) and the median survival was 11.6 months. On multivariate analysis, lower performance status (Karnofsky performance status, 50%-70%) and unresectable organ metastases were significantly associated with poor survival, with hazard ratios of 2.92 and 4.44, respectively. In primary cancer type, lung and kidney cancer were also significantly associated with poor survival, with hazard ratios of 4.25 and 2.60, respectively. The revised Tokuhashi score groups were significantly correlated with the survival groups (&rgr; = 0.530, P < 0.001). In 67 (79%) of 85 patients, actual survival matched the predicted survival. Conclusion. Lower score on performance status, the existence of organ metastases, and primary cancer of the lung and the kidney were significantly associated with poor survival. The revised Tokuhashi score was found to be very useful to predict survival regardless of the treatment pathway. In most patients, actual survival matched their predicted survival.

Craniovertebral junction: biomechanical considerations.

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Radiation exposure to the spine surgeon in lumbar and thoracolumbar fusions with the use of an intraoperative computed tomographic 3-dimensional imaging system.

Study Design. A prospective clinical research article. Objective. The primary goals were to determine (1) radiation exposure to the spine surgeon with the use of an intraoperative 3-dimensional imaging system and (2) to define the safe distance from the computed tomographic scanner. Summary of Background. Intraoperative radiation exposure to the spinal surgeon has been assessed during 2-dimensional fluoroscopy but has not been investigated during intraoperative 3-dimensional imaging. Methods. Ten patients undergoing lumbar or thoracolumbar fusion were enrolled in a prospective trial to determine the radiation exposure to a spine surgeon standing in the substerile room, with the use of the O-ARM Imaging System (Medtronic, Memphis, TN). A thermolucent digital dosimeter was worn at chest level without a lead apron. Dosimeter readings and distance from the spine surgeon were recorded. Results. Average surgeon exposure was 44.22 ± 17.4 &mgr;rem (range: 17.71–70.76 &mgr;rem). The mean distance from the O-ARM was 4.56 ± .32 m, and the surgeon was exposed for an average of 19.6 ± 5.7 seconds (range: 8.05–28.7 s). The annual number of necessary procedures required to surpass the exposure limit, according to the data presented here, would be 113,071 operations using O-ARM. Hence, the number of necessary procedures for O-ARM use is predicted to be 1,130,710 annual procedures to reach the occupational exposure limits for extremity, skin, and all other organs and 339,213 procedures to reach the limits for the lens of eye. Conclusion. Radiation exposure is minimal to the surgical team during routine use of the O-ARM imaging system. The number of procedures required to surpass occupational exposure limits is high if using appropriate distance from the O-ARM.

The use of allograft bone in spine surgery: is it safe?

BACKGROUND CONTEXT Allograft bone is commonly used in various spinal surgeries. The large amount of recalled allograft tissue, particularly in recent years, has increased concerns regarding the safety of allograft bone for spinal surgery. An analysis of allograft recall and its safety in spinal surgery has not been reported previously. PURPOSE To determine 1) the number and types of allograft recall and the reasons for recall, 2) the types of disease transmission to spine patients, and 3) assess the safety of allograft bone in spinal surgery. STUDY DESIGN/SETTING Retrospective review. METHODS A retrospective review of all Food and Drug Administration (FDA) data from 1994 to June 2007 was reviewed to determine the amount and types of recalled allograft tissue. The literature and data from the Center for Disease Control were reviewed to determine the number and types of disease transmissions from allograft bone that have occurred to spine surgery patients during the study period. RESULTS There were 59,476 musculoskeletal allograft tissue specimens recalled by FDA during the study period, which accounts for 96.5% of all allograft tissue recalled in the United States. Improper donor evaluation, contamination, and recipient infections are the main reasons for allograft recall. There has been one case of human immunodeficiency virus infection transmission to a spine surgery patient in 1988. This is the only reported case of viral transmission. There are no reports of bacterial disease transmission from the use of allograft bone to spine surgery patients. CONCLUSIONS The precise number of allografts used in spine surgery annually and the precise incidence of disease transmission to spine surgery patients linked to the use of allograft tissue is unknown. Musculoskeletal allograft tissue accounts for the majority of recalled tissue by FDA. Despite the large number of allograft recalls in this country, there is only one documented case in the literature of disease transmission to a spine surgery patient. There appears to be no overt risk associated with the use of allograft bone in spine surgery. However, as discussed in this article, there are certain aspects regarding the use of allograft bone that should be considered.

Differences in the surgical treatment of recurrent lumbar disc herniation among spine surgeons in the United States

BACKGROUND CONTEXT There are often multiple surgical treatment options for a spinal pathology. In addition, there is a lack of data that define differences in surgical treatment among surgeons in the United States. PURPOSE To assess the surgical treatment patterns among neurologic and orthopedic spine surgeons in the United States for the treatment of one- and two-time recurrent lumbar disc herniation. STUDY DESIGN Electronic survey. PATIENT SAMPLE An electronic survey was delivered to 2,560 orthopedic and neurologic surgeons in the United States. OUTCOME MEASURES The response data were analyzed to assess the differences among respondents over various demographic variables. The probability of disagreement is reported for various surgeon subgroups. METHODS A survey of clinical and radiographic case scenarios that included a one- and two-time lumbar disc herniation was electronically delivered to 2,560 orthopedic and neurologic surgeons in the United States. The surgical treatment options were revision microdiscectomy, revision microdiscectomy with in situ fusion, revision microdiscectomy with posterolateral fusion using pedicle screws, revision microdiscectomy with posterior lumbar interbody fusion/transforaminal lumbar interbody fusion (PLIF/TLIF), anterior lumbar interbody fusion (ALIF) with percutaneous screws, ALIF with open posterior instrumentation, or none of these. Significance of p=.01 was used to account for multiple comparisons. RESULTS Four hundred forty-five surgeons (18%) completed the survey. Surgeons in practice for 15+ years were more likely to select revision microdiscectomy compared with surgeons with fewer years in practice who were more likely to select revision microdiscectomy with PLIF/TLIF (p<.001). Similarly, those surgeons performing 200+ surgeries per year were more likely to select revision microdiscectomy with PLIF/TLIF than those performing fewer surgeries (p=.003). No significant differences were identified for region, specialty, fellowship training, or practice type. Overall, there was a 69% and 22% probability that two randomly selected spine surgeons would disagree on the surgical treatment of two- and one-time recurrent disc herniations, respectively. This probability of disagreement was consistent over multiple variables including geographic, practice type, fellowship training, and annual case volume. CONCLUSIONS Significant differences exist among US spine surgeons in the surgical treatment of recurrent lumbar disc herniations. It will become increasingly important to understand the underlying reasons for these differences and to define the most cost-effective surgical strategies for these common lumbar pathologies as the United States moves closer to a value-based health-care system.

The impact of preoperative depression on quality of life outcomes after lumbar surgery

BACKGROUND CONTEXT Some, smaller studies have investigated the effect of preoperative depression on postoperative improvement in quality of life (QOL). However, they have not used the Patient Health Questionnaire 9 (PHQ-9) in self-reported depression. PURPOSE To assess the effect of preoperative depression as measured by the PHQ-9 on postoperative improvement in QOL. STUDY DESIGN A retrospective review at a single tertiary-care referral center. PATIENT SAMPLE Patients who underwent lumbar decompression or fusion between 2008 and 2012. OUTCOMES MEASURES A self-reported EuroQol five-dimensions (EQ-5D) quality-adjusted life-years Index. METHODS Quality of life data were collected using the institutional prospectively collected database of patient-reported health status measures. The EQ-5D questionnare, PDQ, and PHQ-9 were used. Linear and logistic regression analyses were performed to assess the impact of preoperative depression on QOL improvement. RESULTS Elevated preoperative pain (PDQ, β=-0.0017, p=.0009) and worsened depression (PHQ-9, β=-0.0044, p=.0359) were significantly associated with diminished postoperative improvement in QOL, as measured by the EQ-5D. Furthermore, greater depression (PHQ-9, odds ratio [OR] 0.93, p<.0001) and pain (PDQ, OR 0.99, p=.02) were associated with significantly diminished postoperative improvement exceeding the minimum clinically important difference. CONCLUSIONS Increased preoperative pain and depression were shown to be associated with significantly reduced improvement in postoperative QOL, as measured by the EQ-5D.