Debdut Biswas

Radiation Exposure from Musculoskeletal Computerized Tomographic Scans

BACKGROUND Computerized tomographic scans are routinely obtained to evaluate a number of musculoskeletal conditions. However, since computerized tomographic scans expose patients to the greatest amounts of radiation of all imaging modalities, the physician must be cognizant of the effective doses of radiation that are administered. This investigation was performed to quantify the effective doses of computerized tomographic scans that are performed for various musculoskeletal applications. METHODS The digital imaging archive of a single institution was retrospectively reviewed to identify helical computerized tomographic scans that were completed to visualize the extremities or spine. Imaging parameters were recorded for each examination, and dosimetry calculator software was used to calculate the effective dose values according to a modified protocol derived from publication SR250 of the National Radiological Protection Board of the United Kingdom. Computerized tomographic scans of the chest, abdomen, and pelvis were also collected, and the effective doses were compared with those reported by prior groups in order to validate the results of the current study. RESULTS The mean effective doses for computerized tomographic scans of the chest, abdomen, and pelvis (5.27, 4.95, and 4.85 mSv, respectively) were consistent with those of previous investigations. The highest mean effective doses were recorded for studies evaluating the spine (4.36, 17.99, and 19.15 mSv for the cervical, thoracic, and lumbar spines, respectively). In the upper extremity, the effective dose of a computerized tomographic scan of the shoulder (2.06 mSv) was higher than those of the elbow (0.14 mSv) and wrist (0.03 mSv). Similarly, the effective dose of a hip scan (3.09 mSv) was significantly higher than those observed with knee (0.16 mSv) and ankle (0.07 mSv) scans. CONCLUSIONS Computerized tomographic scans of the axial and appendicular skeleton are associated with substantially elevated radiation exposures, but the effective dose declines substantially for anatomic structures that are further away from the torso.

Normal functional range of motion of the cervical spine during 15 activities of daily living.

Study Design Prospective clinical study. Objective The purpose of this investigation was to quantify normal cervical range of motion (ROM) and compare these results to those used to perform 15 simulated activities of daily living (ADLs) in asymptomatic subjects. Summary of Background Data Previous studies looking at cervical ROM during ADLs have been limited and used measuring devices that do not record continuous motion. The purpose of this investigation was to quantify normal cervical ROM and compare these results with those used to perform 15 simulated ADLs in asymptomatic subjects. Methods A noninvasive electrogoniometer and torsiometer were used to measure the ROM of the cervical spine. The accuracy and reliability of the devices were confirmed by comparing the ROM values acquired from dynamic flexion/extension and lateral bending radiographs to those provided by the device, which was activated while the radiographs were obtained. Intraobserver reliability was established by calculating the intraclass correlation coefficient for repeated measurements on the same subjects by 1 investigator on consecutive days. These tools were employed in a clinical laboratory setting to evaluate the full active ROM of the cervical spines (ie, flexion/extension, lateral bending, and axial rotation) of 60 asymptomatic subjects (30 females and 30 males; age, 20 to 75 y) as well as to assess the functional ROM required to complete 15 simulated ADLs. Results When compared with radiographic measurements, the electrogoniometer was found to be accurate within 2.3±2.2 degrees (mean±SD) and the intraobserver reliabilities for measuring the full active and functional ROM were both excellent (intraclass correlation coefficient of 0.96 and 0.92, respectively). The absolute ROM and percentage of full active cervical spinal ROM used during the 15 ADLs was 13 to 32 degrees and 15% to 32% (median, 20 degrees/19%) for flexion/extension, 9 to 21 degrees and 11% to 27% (14 degrees/18%) for lateral bending, and 13 to 57 degrees and 12% to 92% (18 degrees/19%) for rotation. Backing up a car required the most ROM of all the ADLs, involving 32% of sagittal, 26% of lateral, and 92% of rotational motion. In general, personal hygiene ADLs such as washing hands and hair, shaving, and applying make-up entailed a significantly greater ROM relative to locomotive ADLs including walking and traveling up and down a set of stairs (P<0.0001); in addition, compared with climbing up these steps, significantly more sagittal and rotational motion was used when descending stairs (P=0.003 and P=0.016, respectively). When picking up an object from the ground, a squatting technique required a lower percentage of lateral and rotational ROM than bending at the waist (P=0.002 and P<0.0001). Conclusions By quantifying the amounts of cervical motion required to execute a series of simulated ADLs, this study indicates that most individuals use a relatively small percentage of their full active ROM when performing such activities. These findings provide baseline data which may allow clinicians to accurately assess preoperative impairment and postsurgical outcomes.

Quantifying the Effects of Age, Gender, Degeneration, and Adjacent Level Degeneration on Cervical Spine Range of Motion Using Multivariate Analyses

Study Design. Retrospective review and multivariate analysis. Objective. Assess cervical spine segmental range of motion (ROM) with flexion/extension (F/E) radiographs and determine the relation to clinical variables. Summary of Background Data. Previous studies investigated the roles of age and degeneration on cervical ROM with univariate analyses. Multivariate analyses are required to account for multiple factors that may affect ROM and quantify their relative effects. Methods. Radiographs of 195 patients were analyzed, including 133 females and 62 males with ages ranging from 15 to 93 years. Segmental ROM and Kellgren score (KS) of degeneration were assessed for C2–C7. Patient’s age and gender were documented. Multivariate analyses were performed for each level. Independent variables evaluated were: (1) KS at the level of interest, (2) KS at the level above, (3) KS at the level below, (4) age, and (5) gender. Significance was defined as P < 0.05. Results. Interobserver reliabilities for assessing KS (intraclass correlation coefficient 0.81) and segmental ROM (intraclass correlation coefficient 0.72) were good to excellent. Age had a significant negative association with ROM at C2–C3, C3–C4, C4–C5, and C5–C6. KS at the level of interest had a significant negative association with ROM at C2–C3, C3–C4, C4–C5, C5–C6, and C6–C7. KS at the inferior segment had a significant positive association with ROM at C2–C3, C3–C4, and C4–C5. Gender had a significant association with ROM only at C2–C3. Conclusion. Age was associated with declining ROM independent of degeneration, amounting to a 5° decrease in subaxial cervical ROM every 10 years. Degeneration was also associated with ROM. For every point increase in KS at a given level, there was an associated 1.2° decrease in ROM at that level, and a 0.8° increase in ROM at the level above. These results provide a framework with which to counsel patients about cervical ROM and a benchmark from which procedure specific changes can be compared.

The incidence of noncontiguous spinal fractures and other traumatic injuries associated with cervical spine fractures: a 10-year experience at an academic medical center.

Study Design. Retrospective medical record review. Objective. The purpose of this study was to describe the incidence of other injuries that commonly occur in conjunction with cervical spine fractures and dislocations. Summary of Background Data. Cervical spine fractures are often associated with other significant traumatic conditions, which may also require prompt diagnosis and management. However, the relative incidences of the injuries that occur in conjunction with various cervical spine fractures have not been well documented. Methods. The radiographic reports of all patients who underwent CT scans of the cervical spine at a single level 1 trauma center over a 10-year period were reviewed. The medical records of individuals with acute, nonpenetrating fractures of the cervical spine were further assessed for any associated traumatic pathology including noncontiguous spine injuries and those affecting other organ systems (i.e., head and neck, intrathoracic, intra-abdominal/pelvic, and nonspinal orthopedic disorders). Results. A total of 13,896 CT scans of the cervical spine were performed during this 10-year period of which 492 revealed acute fractures and/or dislocations. Of these subjects, 60% had sustained at least one additional injury. Overall, 57% were noted to have extraspinal injuries (34% head and neck, 17% intrathoracic, 10% intra-abdominal/pelvic, and 30% nonspinal orthopedic conditions) and noncontiguous spinal trauma was present in 19% of these cases (8% cervical injuries, 8% thoracic, and 6% lumbar). In general, the rates of associated injuries observed with occipital condyle and C7 fractures were significantly higher than those recorded for other cervical segments. Conclusion. For patients with a known history of cervical spine trauma, the frequencies of associated injuries were similar across all levels of the cervical spine with the exception of the injuries to the craniocervical junctions. In practice, this means that injuries to the cervical spine can likely be grouped together when considering other possible associated injuries. Further elucidation of these injury patterns will likely be useful for facilitating the expedient evaluation and proper management of these individuals.

Sterility of C-arm fluoroscopy during spinal surgery

Study Design. Prospective study evaluating the sterility of 25 C-arm drapes after their use during spine surgery. Objective. To use swab samples to evaluate the sterility of draped C-arms at the end of spine surgical cases and assess the integrity of the sterile technique. Summary of Background Data. Intraoperative fluoroscopy is used routinely in the operating room for a variety of spinal applications. Although the C-arm may help the surgeon assess spinal alignment and facilitate the placement of instrumentation, there are concerns that the C-arm may represent a potential source of contamination and increase the risk of developing a postoperative infection. Methods. This study included 25 surgical cases requiring a standard fluoroscopic C-arm that were performed by 2 spine surgeons. Sterile culture swabs were used to obtain samples from 5 defined locations on the C-arm drape after its use during the operation. The undraped technician’s console was sampled in each case as a positive control and an additional 25 C-arm drapes were swabbed immediately after they were applied to the C-arm unit in order to obtain negative controls. Swab samples were assessed for bacterial growth on 5% sheep blood Columbia agar plates using a semiquantitative technique. Results. Contamination was noted on only 1 of 25 negative control drapes at a single location (4%). One hundred percent and 96% of the positive control swabs that were obtained from the negative controls and postoperative drapes exhibited growth, respectively. Although at least some degree of contamination was observed at all locations of the C-arm drape after surgery, the upper 2 sample sites demonstrated the greatest degree of contamination; the incidences of postoperative contamination were significantly greater for the top (56%, P < 0.000001) and upper front of the receiver (28%, P = 0.010) compared to the negative controls. In contrast, the lower front, receiver plate, and midportion of the C-arm were associated with lower rates of contamination (12%–20%). Conclusion. The upper portions of the C-arm clearly exhibited the greatest rates of contamination during spinal operations. This contamination most likely occurs when the undraped portions of the C-arm are rotated to acquire lateral images. As a result, we no longer consider the top portion of the C-arm drape to be sterile in these situations and we believe that avoiding contact with these areas may decrease the risks of intraoperative contamination and possibly postoperative infection as well.

Quantifying the effects of degeneration and other patient factors on lumbar segmental range of motion using multivariate analysis.

Study Design. Retrospective review and multivariate analysis. Objectives. Assess lumbar spine segmental range of motion (ROM) with flexion/extension (F/E) radiographs and determine the relation to clinical variables. Summary of Background Data. Prior studies have investigated the roles of age and degeneration on lumbar segmental ROM only using univariate analyses. Multivariate analyses are also required to differentiate the multiple factors that may affect ROM and quantify their relative effects. Methods. Radiographs of 258 patients were analyzed, including 137 females and 121 males with ages ranging from 18 to 92 years. Segmental ROM and Kellgren score (KS) of degeneration were assessed for L1–S1. Multivariate regression analyses were performed for each level. Predicting variables evaluated were: (1) KS at the level of interest, (2) KS at the level above, (3) KS at the level below, (4) age, (5) gender, (6) weight, (7) height, (8) body mass index (BMI), and (9) smoking. Significance was defined as P < 0.05. Results. Interobserver reliabilities for assessing KS (ICC 0.70) and segmental ROM (ICC 0.80) were good to excellent. In the multivariate analyses, age had a significant negative association with ROM at L1–L2, L2–L3, L3–L4, and L4–L5. BMI had a significant negative association with ROM at L2–L3, L3–L4, and L4–L5. KS at the level of interest had significant negative association with ROM only at L5–S1. KS at adjacent levels, gender, weight, height, and smoking did not have a significant association with ROM at any level. Conclusion. The results of this study provide the clinician with insight into factors that influence segmental lumbar ROM. Age was the strongest statistical predictor of ROM and was associated with declining ROM, amounting to an approximate 3° decrease in total sagittal lumbar ROM in the superior 4 segments every 10 years. BMI was another factor associated with lumbar ROM. Degeneration was a significant predictor of ROM only at L5–S1.

Actual knee motion during continuous passive motion protocols is less than expected.

Investigations of the usefulness of continuous passive motion (CPM) after TKA have yielded mixed results, with evidence suggesting its efficacy is contingent on the presence of larger motion arcs. Surprisingly, the range of motion (ROM) the knee actually experiences while in a CPM machine has not been elucidated. In this study, the ability of a CPM apparatus to bring about a desired knee ROM was assessed with an electrogoniometer. The knee experienced only 68% to 76% of the programmed CPM arc, with the higher percentages generated by elevating the head of the patient’s bed. This disparity between true knee motion and CPM should be accounted for when designing CPM protocols for patients or investigations evaluating efficacy of CPM.

rhBMP-2 (ACS and CRM formulations) overcomes pseudarthrosis in a New Zealand white rabbit posterolateral fusion model.

Study Design. The study design consisted of a New Zealand white rabbit model of pseudarthrosis repair. Study groups consisting of no graft, autograft, or recombinant human bone morphogenetic protein-2 (rhBMP-2) with absorbable collagen sponge (ACS) or compression resistant matrix (CRM) were evaluated. Objective. To evaluate the relative efficacy of bone graft materials (autograft, ACS, and CRM). Summary of Background Data. rhBMP-2 has been shown to have a 100% fusion rate in a primary rabbit fusion model, even in the presence of nicotine, which is known to inhibit fusion. Methods. Seventy-two New Zealand white rabbits underwent posterolateral lumbar fusion with iliac crest autograft. To establish pseudarthroses, nicotine was administered to all animals. At 5 weeks, the spines were explored and all pseudarthroses were redecorticated and implanted with no graft, autograft, rhBMP-2/ACS, or rhBMP-2/CRM. At 10 weeks, fusions were assessed by manual palpation and histology. Results. Eight rabbits (11%) were lost to complications. At 5 weeks, 66 (97%) had pseudarthroses. At 10 weeks, attempted pseudarthrosis repairs were fused in 1 of 16 of no graft rabbits (6%), 5 of 17 autograft rabbits (29%), and 31 of 31 rhBMP-2 rabbits (with ACS or CRM) (100%). Histologic analysis demonstrated more mature bone formation in the rhBMP-2 groups. Conclusions. The 2 rhBMP-2 formulations led to significantly higher fusion rates and histologic bone formation than no graft and autograft controls in this pseudarthrosis repair model.