Volar and Dorsal Blood Supply to the Lunate: A Cadaveric Study.

Although various studies have proposed vascular and mechanical factors, the etiology of Kienböck disease is unknown. Kienböck theorized that lunatomalacia resulted from traumatic disruption of blood supply and bony nutrition to the lunate. Extraosseous supply to the lunate, as far as volar or dorsal vessels are concerned, is still controversial. This study evaluated the extraosseous nutrient foramina from the dorsal and volar aspects of lunate specimens. A total of 913 specimens from the Hamann-Todd Osteological Collection in Cleveland, Ohio, were examined. The nutrient artery foramina on left and right lunate specimens were examined from dorsal and volar aspects. The number of nutrient artery foramen was tabulated. Age, sex, and race data were collected. Specimens were divided into groups according to the number of nutrient artery foramina, and the dorsal and volar foramina were compared. The average number of foramina on the dorsal aspect of the lunate (1.71) was greater than the volar aspect (1.64), except in specimens younger than 35 years. A greater number of specimens had 3 or more foramina on the dorsal side compared with the volar aspect. Based on this study, there was significant contribution of dorsal arterial vessels to the blood supply of lunate specimens older than 35 years, which contrasts with findings in earlier studies. The disruption of dorsal intercarpal and radiocarpal ligaments leading to the disruption of the dorsal arterial arches may contribute to vascular insufficiency of the lunate and should be evaluated further in the etiopathogenesis of Kienböck disease. [Orthopedics. 2021;44(2):e243-e247.].

Cervicothoracic Pedicle Morphometry: Using an Osteological Collection to Characterize Trends in Pedicle Size.

Pedicle screws are a common treatment option for spinal instability. Despite their popularity, pedicle screws carry the risk of transpedicular violation with subsequent neural and vascular damage. This study measured the pedicle dimensions of 500 dry specimens in an osteological collection. The data provide the orthopedic spine surgeon with an accurate measure of pedicle morphometry in light of previously limited and contradictory results. The study demonstrates that pedicle height at the cervicothoracic junction tends to increase with body height, particularly for females. Additionally, T1 pedicle width is smaller for females than males and, for males, tends to decrease with increasing body weight. These results are valuable to the spine surgeon because they suggest that taller patients may afford a larger margin for error in the vertical plane. However, they also demonstrate that heavier patients do not have wider pedicles and thus cannot be assumed to tolerate or require larger-diameter screws. (Journal of Surgical Orthopaedic Advances 27(1):33-38, 2018).

Spondylolysis and End Plate Arthrosis at L5-S1: A Cadaveric Study.

This study examined the effect of bilateral and unilateral L5 pars defects on the degree of disk degeneration at the L5-S1 level in cadaveric specimens. An observational study was performed of 690 cadaveric specimens selected at random. These specimens represent individuals who died between 1893 and 1938. The study included 558 male and 132 female cadavers. Of the 120 specimens with L5 spondylolysis, 95 cases were bilateral and 25 were unilateral. The remaining 544 specimens were used as the control cohort. Degenerative disk disease was measured by the classification of Eubanks et al. According to this classification, degenerative disk disease was graded from no arthrosis (grade 0) to complete ankylosis (grade IV). Linear regression analysis corrected for age, sex, and race showed that subjects with bilateral spondylolysis at L5 had a statistically significant increase in the amount of disk degeneration (P=.02) compared with those with unilateral lesions. Student's t tests showed significant differences (P<.001 and P=.002, respectively) in the amount of degeneration seen with both bilateral and unilateral spondylolysis above what would be predicted in the normal control population. A positive correlation was found between the number of pars defects at L5 and the degree of disk degeneration at L5-S1. These results support the idea that individuals with spondylolysis at these levels may be at increased risk for development of low back pain and reduced quality of life. [Orthopedics. 2017; 40(1):e59-e64.].

Calcaneocuboid Joint Arthritis of the Midfoot Precedes Tibiotalar Joint Arthritis.

Surgical models have best shown the relationship between ankle and mid-foot osteoarthritis, although findings regarding the calcaneocuboid joint have varied. To the authors' knowledge, no studies have evaluated the relationship between degenerative changes across the tibiotalar and calcaneocuboid joints. The goal of this study was to determine whether such a relationship exists and which joint degenerates first. A single examiner evaluated 694 tibiotalar and calcaneocuboid joints to determine the presence of osteoarthritis. Multiple linear regression analysis was conducted with a standard P value cutoff (P<.05) and 95% confidence interval. The average incidence of tibiotalar and calcaneocuboid osteoarthritis in specimens older than 40 years was compared with the incidence in those 40 years and younger. A positive correlation between tibiotalar and calcaneocuboid osteoarthritis was noted. African-American subjects were less likely than white subjects to have tibiotalar osteoarthritis. The finding of right and left tibiotalar and calcaneocuboid osteoarthritis in subjects 40 years and younger showed that midfoot arthritis was significantly more common than arthritis of the ankle. The prevalence of calcaneocuboid osteoarthritis remains stable after 40 years of age, and the prevalence of tibiotalar osteoarthritis approaches that of calcaneocuboid osteoarthritis. Calcaneocuboid osteoarthritis precedes tibiotalar osteoarthritis. Altered biomechanics involved in calcaneocuboid osteoarthritis are transferred to the tibiotalar joint, leading to tibiotalar osteoarthritis as the subject ages. Early education, surveillance, physical therapy, shoe adjustment, and orthotics may help to reduce the forces across the midfoot and prevent ankle arthritis in the long term. [Orthopedics. 2016; 39(6):e1112-e1116.].

Most 30-day Readmissions After Anterior Cervical Discectomy and Fusion Are Not Due to Surgical Site-Related Issues: An Analysis of 17,088 Patients.

STUDY DESIGN: A retrospective study of patients undergoing anterior cervical discectomy and fusion (ACDF) in the prospective National Surgical Quality Improvement Program (NSQIP) database. OBJECTIVE: To determine the most common reasons for readmission within 30 days after elective ACDF. SUMMARY OF BACKGROUND DATA: ACDF is a commonly performed surgery that is safe and effective for treating a variety of cervical spine pathologies. With new quality-based reimbursements tied to readmissions within 30 days of discharge, better understanding of the causes of readmissions is, however, needed. METHODS: Patients undergoing ACDF in the NSQIP database from 2012 to 2014 were reviewed. The overall rate of readmission and documented reasons for readmission were collected. Multivariate regression was then used to determine risk factors for readmissions. RESULTS: A total of 17,088 patients undergoing elective ACDF were identified. There were 545 (3.2%) readmissions within 30 postoperative days. Of the readmitted patients, 293 (53.8%) were readmitted for nonsurgical site-related reasons, with neuropsychiatric (n = 44), cardiovascular (n = 39), and pneumonia (n = 37) being the most common reasons. A total of 184 patients (33.8%) were readmitted for surgical site-related reasons, with surgical site infection (n = 42), hemorrhage/hematoma (n = 42), and dysphagia (n = 32) being the most common reasons. A total of 84 patients (15.6%) had undocumented reasons for readmission. In multivariate analysis, only older age and higher American Society of Anesthesiologists class were independently associated with readmissions. CONCLUSION: Most readmissions after ACDF were due to nonsurgical site-related reasons, suggesting the importance of careful patient selection, aggressive preoperative medical optimization, and adequate postoperative management. LEVEL OF EVIDENCE: 3.

Bilateral Pars Defects at the L4 Vertebra Result in Increased Degeneration When Compared With Those at L5: An Anatomic Study.

BACKGROUND: Cadaveric studies have examined disc degeneration at the L4-L5 and L5-S1 motion segments; however, we are not aware of another study that has examined the relationship between bilateral spondylolysis and its effect on degenerative disc disease at those levels. This may have been overlooked by researchers owing to the majority of spondylolysis occurring at the L5 vertebra. QUESTIONS/PURPOSES: Using osteologic specimens from a collection that included individuals who died in one city in the USA between 1893 and 1938, we asked: (1) do specimens with bilateral spondylolysis (bilateral pars defects) have increased levels of disc degeneration, at their respective motion segments, when compared with matched controls without spondylolysis, and (2) is the finding of a bilateral pars defect associated with more severe arthritis at L4-L5 than at L5-S1? METHODS: An observational study was performed on 665 skeletal lumbar spines from the Hamann-Todd Osteologic Collection at the Cleveland Museum of Natural History (Cleveland, OH, USA). The specimens included 534 males and 131 females ranging from 17 to 87 years old, with a nearly bell-shaped distribution of ages for males and a larger proportion of younger ages in the female specimens. Of those with spondylolysis, 81 had a defect at L5 and 14 had a defect at L4. The gross specimens were examined subjectively for evidence of arthrosis. At the time of examination, specific attention was not paid to the coexisting presence or absence of spondylolysis nor was the examiner blinded to the age of the specimens. Disc degeneration was measured by the classification of Eubanks et al., a modified version of the Kettler and Wilke classification. Linear regression was performed to derive a formula that would predict the amount of disc degeneration at L4-L5 and L5-S1 for the normal control population given a specimen's age, sex, and race. We then used this formula to evaluate the difference in disc degeneration at the corresponding level of the pars defect that is greater than the predicted amount for a control without spondylolysis. This allowed us to conclude that any significant differences found between the L4-L5 and L5-S1 cohorts were attributable to factors not simply inherent to their functional position in the spine of an individual without a bilateral pars defect. RESULTS: L4 spondylolysis and L5 spondylolysis showed greater amounts of degeneration compared with that of matched controls (L4 controls: mean = 1.52, SD = 0.74; L4 spondylolysis: mean = 3.21, SD = 0.87; p < 0.001; L5 controls: mean = 0.97, SD = 0.48; L5 spondylolysis: mean = 2.06, SD = 0.98; p < 0.001). When we controlled for the expected amount of degenerative disc disease at each level in controls, the observed degeneration was more severe at L4-L5 than at L5-S1 (p = 0.008, R-squared = 18.6). CONCLUSIONS: L4-L5 and L5-S1 bilateral spondylolysis groups had increased presence of degenerative disc disease compared with those without bilateral spondylolysis. For the same degree of spondylolysis, the observed amount of disc degeneration was greater at the L4-5 motion segment compared with L5-S1. CLINICAL RELEVANCE: Although not as common as the spondylolysis at L5-S1, we believe that our findings support that patients with L4-L5 spondylolysis can expect a greater degree of degenerative disc disease and increasing clinical symptoms. Multiple factors in the sacropelvic geometry of an individual, facet morphologic features at L4-L5, and the absence of the iliolumbar ligament at this level are possible contributing factors to the findings of this study.

Length of Stay and Readmission After Total Shoulder Arthroplasty: An Analysis of 1505 Cases.

We conducted a study to characterize the risk factors for extended length of stay (LOS) and readmission after primary total shoulder arthroplasty (TSA). Patients who were 60 years or older and underwent TSA between 2011 and 2012 were identified from the American College of Surgeons National Surgical Quality Improvement Program database. Bivariate and multivariate analyses were used to test patient characteristics for association with extended LOS and readmission within 30 days. Extended LOS was defined as LOS of more than 3 days (90th percentile LOS). Of the 1505 TSA patients identified, 49 (3.3%) were readmitted. Multivariate analysis revealed that extended LOS was independently associated with age 70 years or older and history of diabetes. Readmission was independently associated with history of heart disease and history of hypertension. The identified risk factors may be useful for preoperative discussions, surgical decision-making, and postoperative planning for THA patients.

Pedicle Morphometry of Lumbar Vertebrae: Male, Taller, and Heavier Specimens Have Bigger Pedicles.

STUDY DESIGN: An anatomic study of pedicle dimensions was performed for lumbar vertebrae from American subjects. OBJECTIVE: To quantify the dimensions of the lumbar pedicles and to better define the demographic factors that could ultimately govern the caliber selection of pedicle screws. SUMMARY OF BACKGROUND DATA: Transpedicular screw fixation allows for segmental instrumentation into multiple vertebrae across multilevel fusion area, offering considerable biomechanical advantage over the conventional hook and lateral mass fixation. Large variations in morphology from previous studies may be related to differences in demographics, sample size, and methodology. METHODS: For this study, L1-L5 vertebrae from 503 American human cadavers were directly measured with a digital caliper. Examiner measured each vertebra to determine medial-lateral pedicle width (PW) and cranial-caudal pedicle height (PH). Demographic information regarding age, sex, and race, as well as body height and weight, was available for all 503 subjects. RESULTS: PH decreased in size caudally down the lumbar spine, but PW increased in size. The largest PH was at the L1 level with a mean of 15.75 mm. The widest PW was at the L5 level with a mean of 18.33 mm. Males have larger pedicles than females for all lumbar levels. The tallest and heaviest groups generally had larger pedicles than the shorter and lighter groups, respectively. Age and race did not consistently affect pedicle dimension in a statistically significant manner. CONCLUSION: Our large-scale study of American specimens characterized the relationship between pedicle dimensions and a variety of demographic factors such as age, sex, body height, and weight. With substantial statistical power, the current study showed that male, taller, and heavier individuals had larger lumbar pedicles. LEVEL OF EVIDENCE: 3.

Undertapping of Lumbar Pedicle Screws Can Result in Tapping With a Pitch That Differs From That of the Screw, Which Decreases Screw Pullout Force.

STUDY DESIGN: Survey of spine surgeons and biomechanical comparison of screw pullout forces. OBJECTIVE: To investigate what may be a suboptimal practice regularly occurring in spine surgery. SUMMARY OF BACKGROUND DATA: In order for a tap to function in its intended manner, the pitch of the tap should be the same as the pitch of the screw. Undertapping has been shown to increase the pullout force of pedicle screws compared with line-to-line tapping. However, given the way current commercial lumbar pedicle screw systems are designed, undertapping may result in a tap being used that has a different pitch from that of the screw (incongruent pitch). METHODS: A survey asked participants questions to estimate the proportion of cases each participant performed in the prior year using various hole preparation techniques. Participant responses were interpreted in the context of manufacturing specifications of specific instrumentation systems. Screw pullout forces were compared between undertapping with incongruent pitch and undertapping with congruent pitch using 0.16 g/cm polyurethane foam block and 6.5-mm screws. RESULTS: Of the 3679 cases in which participants reported tapping, participants reported line-to-line tapping in 209 cases (5%), undertapping with incongruent pitch in 1156 cases (32%), and undertapping with congruent pitch in 2314 cases (63%). The mean pullout force for undertapping with incongruent pitch was 56 N (8%) less than the mean pullout force for undertapping with congruent pitch. This is equivalent to 13 lb. CONCLUSION: This study estimates that for about 1 out of every 3 surgical cases with tapping of lumbar pedicle screws in the United States, hole preparation is being performed by undertapping with incongruent pitch. This study also shows that undertapping with incongruent pitch results in a decrease in pullout force by 8% compared with undertapping with congruent pitch. Steps should be taken to correct this suboptimal practice. LEVEL OF EVIDENCE: 3.

Lumbar degenerative disc disease and tibiotalar joint arthritis: a 710-specimen postmortem study.

Research has associated lumbar spinal disease with lower extremity arthrosis. These studies focused solely on the lumbar spine's connection with hip or knee pathology, failing to investigate potential ankle relationships. We specifically explored the interplay between lumbar disc degeneration and tibiotalar joint arthritis. Lumbar disc degeneration and tibiotalar joint arthritis was graded 0 to 4, according to osteophytosis of the vertebral rim and talar surface in 710 randomly selected cadaveric specimens. We corrected for confounding factors of age, sex, race, and height. A significant association was found between lumbar disc degeneration and tibiotalar joint arthritis (P < .01). Lumbar disc degeneration encompassing 3 intervetebral discs demonstrated the highest odds for development of severe tibiotalar joint arthritis. Severe lumbar degenerative disc disease was more prevalent than severe tibiotalar joint arthritis in individuals age 20 years and older. Furthermore, the presence of severe lumbar degeneration significantly predisposes individuals to the development of severe ankle arthritis (P < .05). Gait changes resulting from disc degeneration or neural compression in the lumbar spine may play a role in ankle osteoarthritis development. This association must be considered when treating patients with lumbar disc degeneration and leg pain.

General compared with spinal anesthesia for total hip arthroplasty.

BACKGROUND: Total hip arthroplasty may be performed under general or spinal anesthesia. The purpose of the current study was to compare perioperative outcomes between anesthetic types for patients undergoing primary elective total hip arthroplasty. METHODS: Patients who had undergone primary elective total hip arthroplasty from 2010 to 2012 were identified from the American College of Surgeons National Surgical Quality Improvement Program database. Operating room times, length of stay, thirty-day adverse events, and readmission were compared between patients who had received general anesthesia and those who had received spinal anesthesia. Propensity-adjusted multivariate analysis was used to control for selection bias and baseline patient characteristics. RESULTS: A total of 20,936 patients who had undergone total hip arthroplasty met inclusion criteria for this study. Of these, 12,752 patients (60.9%) had received general anesthesia and 8184 patients (39.1%) had received spinal anesthesia. On propensity-adjusted multivariate analyses, general anesthesia for total hip arthroplasty was associated with increased operative time (+12 minutes [95% confidence interval, +11 to +13 minutes]; p < 0.001) and postoperative room time (+5 minutes [95% confidence interval, +4 to +6 minutes]; p < 0.001). General anesthesia was also associated with the occurrence of any adverse event (odds ratio, 1.31 [95% confidence interval, 1.23 to 1.41]; p < 0.001), prolonged postoperative ventilator use (odds ratio, 5.81 [95% confidence interval, 1.35 to 25.06]; p = 0.018), unplanned intubation (odds ratio, 2.17 [95% confidence interval, 1.11 to 4.29]; p = 0.024), stroke (odds ratio, 2.51 [95% confidence interval, 1.02 to 6.20]; p = 0.046), cardiac arrest (odds ratio, 5.04 [95% confidence interval, 1.15 to 22.07]; p = 0.032), any minor adverse event (odds ratio, 1.35 [95% confidence interval, 1.25 to 1.45]; p = 0.001), and blood transfusion (odds ratio, 1.34 [95% confidence interval, 1.25 to 1.45]; p < 0.001). General anesthesia was not associated with any difference in preoperative room time, postoperative length of stay, or readmission. CONCLUSIONS: General anesthesia was associated with an increased rate of adverse events and mildly increased operating room times.

Lower thoracic pedicle morphometry: male, taller, and heavier specimens have bigger pedicles.

STUDY DESIGN: An anatomic study of pedicle dimensions was performed for lower thoracic vertebrae from American human subjects. OBJECTIVE: To quantify the dimensions of the lower thoracic pedicles and to better define the demographic factors that could ultimately govern the caliber selection of pedicle screws. SUMMARY OF BACKGROUND DATA: Transpedicular screw fixation allows for segmental instrumentation into multiple vertebrae across multilevel fusion area, offering considerable biomechanical advantage over the conventional hook and lateral mass fixation. Large variations in morphology from previous studies may be related to differences in demographics, sample size, and methodology. METHODS: For this study, T7-T12 vertebrae from 503 American human cadavers were directly measured with a digital caliper. Examiner measured each vertebra to determine medial-lateral pedicle width and cranial-caudal pedicle height. Demographic information regarding age, sex, and race, as well as body height and weight, was available for all 503 subjects. RESULTS: Both pedicle height and pedicle width generally increased in size caudally down the lower thoracic spine. The highest pedicle height was at the T12 level with a mean of 17.08 mm. The widest pedicle width was at the T11 level with a mean of 9.31 mm. Males have larger pedicles than females for all upper thoracic levels. The tallest and heaviest groups had larger pedicles than the shorter and lighter groups, respectively. Age and race did not consistently affect pedicle dimension in a statistically significant manner. CONCLUSION: Our large-scale study of American specimens characterized the relationship between pedicle dimensions and a variety of demographic factors such as age, sex, body height and weight. With substantial statistical power, this study showed that male, taller, and heavier individuals had larger pedicles. LEVEL OF EVIDENCE: N/A.

Use of an operating microscope during spine surgery is associated with minor increases in operating room times and no increased risk of infection.

STUDY DESIGN: Retrospective database review. OBJECTIVE: To evaluate whether microscope use during spine procedures is associated with increased operating room times or increased risk of infection. SUMMARY OF BACKGROUND DATA: Operating microscopes are commonly used in spine procedures. It is debated whether the use of an operating microscope increases operating room time or confers increased risk of infection. METHODS: The American College of Surgeons National Surgical Quality Improvement Program database, which includes data from more than 370 participating hospitals, was used to identify patients undergoing elective spinal procedures with and without the use of an operating microscope for the years 2011 and 2012. Bivariate and multivariate linear regressions were used to test the association between microscope use and operating room times. Bivariate and multivariate logistic regressions were similarly conducted to test the association between microscope use and infection occurrence within 30 days of surgery. RESULTS: A total of 23,670 elective spine procedures were identified, of which 2226 (9.4%) used an operating microscope. The average patient age was 55.1±14.4 years. The average operative time (incision to closure) was 125.7±82.0 minutes.Microscope use was associated with minor increases in preoperative room time (+2.9 min, P=0.013), operative time (+13.2 min, P<0.001), and total room time (+18.6 min, P<0.001) on multivariate analysis.A total of 328 (1.4%) patients had an infection within 30 days of surgery. Multivariate analysis revealed no significant difference between the microscope and nonmicroscope groups for occurrence of any infection, superficial surgical site infection, deep surgical site infection, organ space infection, or sepsis/septic shock, regardless of surgery type. CONCLUSION: We did not find operating room times or infection risk to be significant deterrents for use of an operating microscope during spine surgery. LEVEL OF EVIDENCE: 3.

Morbidity, mortality, and readmission after vertebral augmentation: analysis of 850 patients from the American College of Surgeons National Surgical Quality Improvement Program database.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To identify risk factors for poor short-term outcomes after vertebral augmentation procedures. SUMMARY OF BACKGROUND DATA: Vertebral compression fractures are the most common fractures of osteoporosis and are frequently treated with vertebroplasty or kyphoplasty. There is a shortage of information about risk factors for short-term, general health outcomes after vertebral augmentation in the literature. METHODS: Patients older than 65 years who underwent vertebroplasty or kyphoplasty in 2011 and 2012 were identified from the American College of Surgeons National Surgical Quality Improvement Program database. Patient characteristics were tested for association with 30-day adverse events, mortality, and readmission using bivariate and multivariate analyses. RESULTS: A total of 850 patients met inclusion criteria. The average age was 78.9±11.7 years (mean±standard deviation) and females made up 70.8% of the cohort. Of these patients, 9.5% had any adverse event (AAE), and 6.6% had a serious adverse event (SAE). Death occurred in 1.5% of patients, and 10.8% were readmitted within the first 30 postoperative days.On multivariate analysis, AAE and SAE were both significantly associated with American Society of Anesthesiologists class 4 (AAE: odds ratio [OR]=2.7, P=0.013; SAE: OR=2.5, P=0.040) and inpatient status before procedure (AAE: OR=2.7, P<0.001, SAE: OR=2.4, P=0.003). Increased postoperative mortality rate was associated with American Society of Anesthesiologists class 4 (OR=6.4, P=0.024) and the use of nongeneral anesthesia (OR=4.0, P=0.022). Readmission was associated with history of pulmonary disease (OR=2.0, P=0.005) and inpatient status before procedure (OR=1.9, P=0.005). CONCLUSION: Adverse general health outcomes were relatively common, and the factors identified in the earlier text associated with patient outcomes after vertebral augmentation may be useful for preoperative discussions and counseling. LEVEL OF EVIDENCE: 3.

Pedicle morphometry of upper thoracic vertebrae: an anatomic study of 503 cadaveric specimens.

STUDY DESIGN: An anatomic study of pedicle dimensions was performed for upper thoracic vertebrae from American human subjects. OBJECTIVE: To quantify the dimensions of the upper thoracic pedicles and to better define the demographic factors that could ultimately govern the caliber selection of pedicle screws. SUMMARY OF BACKGROUND DATA: Transpedicular screw fixation allows for segmental instrumentation into multiple vertebrae across multilevel fusion area, offering considerable biomechanical advantage over the conventional hook and lateral mass fixation. Large variations in morphology from previous studies may be related to differences in demographics, sample size, and methodology. METHODS: For this study, T1-T6 vertebrae from 503 American human cadavers were directly measured with a digital caliper. Examiner measured each vertebra to determine medial-lateral pedicle width and cranial-caudal pedicle height. Demographic information regarding age, sex, and race, as well as body height and weight, was available for all 503 subjects. RESULTS: Pedicle height generally increased in size caudally down the upper thoracic spine, but the highest pedicle height was at the T3 level with a mean of 12.25 mm. Pedicle width displayed a narrowing pattern moving down. The widest pedicle width was at the T1 level with a mean of 8.66 mm. The 2 older age groups had larger pedicles than the 2 younger age groups. Males have larger pedicles than females for all upper thoracic levels. The tallest and heaviest groups had larger pedicles than the shorter and lighter groups, respectively. Race was not a significant factor in affecting pedicle dimension. CONCLUSION: Our large-scale study of American specimens characterized the relationship between pedicle dimensions and a variety of demographic factors such as age, sex, body height, and weight. With substantial statistical power, this study showed that male, older, taller, and heavier individuals had larger pedicles. LEVEL OF EVIDENCE: N/A.

Osteochondritis dissecans of the talus: diagnosis and treatment in athletes.

Osteochondritis dissecans of the talus is a subset of osteochondral lesions of the talus that also includes osteochondral fractures, avascular necrosis, and degenerative arthritis. Osteochondral lesions of the talus can be associated with injury to the ankle. This article discusses the anatomy, pathoanatomy, history, physical examination, imaging, management algorithm, and outcomes of surgical treatment of osteochondral lesions in these patients. This article also presents the authors' recommended surgical technique.

Disk degeneration in lumbar spine precedes osteoarthritic changes in hip.

It is not clear whether spinal degeneration leads to hip arthritis, or hip arthritis leads to spinal degeneration. We conducted a study to determine which degenerative process precedes the other. We examined 340 cadaveric human specimens from the Hamann-Todd Osteological Collection (Cleveland, Ohio). Lumbar endplate degeneration was graded on a scale of 0 to 4, and hip degeneration on a scale of 0 to 3. Linear regression was used to analyze the relationship between hip osteoarthritis (OA) and lumbar degenerative disk disease (DDD). Exact tests were used to identify differences in each age group. Hip OA was significantly associated with endplate degeneration at the L1, L3, and L5 levels (P<.02). Of the specimens younger than 29 years, 35% had evidence of DDD in at least 1 lumbar level, and 17% of hip OA changes. At 70 years, 100% of the specimens had evidence of DDD and 50% of hip OA changes. There was a significant association between lumbar DDD and hip OA changes (P<.05). Early lumbar DDD was twice as common as hip OA changes in the early 20s age range. These findings suggest that lumbar degeneration precedes hip degeneration and may be a causative factor for hip OA.

Application of a correlation between the lumbar Torg ratio and the area of the spinal canal to predict lumbar stenosis: a study of 420 postmortem subjects.

BACKGROUND: A cervical Torg ratio of 0.8 has been used as a screening tool to determine the presence of cervical spinal stenosis. However, there have been no studies done to define the Torg ratio in the lumbar spine for predicting lumbar spinal stenosis (LSS). Torg ratios have never been correlated with the actual calculated canal area as derived from anatomic specimens. The aim of this study was to provide an analysis of the utility of the lumbar Torg ratio for predicting LSS based on objective measurements of skeletal specimens. MATERIALS AND METHODS: 420 adult skeletal specimens from the Hamann Todd Collection in the Cleveland Museum of Natural History were selected. Digital calipers were used to measure the sagittal diameter (SCD), interpedicular distance, pedicle length, and vertebral body diameter. The canal area at each level was calculated using a geometric formula. A standard distribution curve for canal area and Torg ratio was created, and values that were that is less than the mean minus two standard deviations (SD) below the mean were considered stenotic. Regression analysis was performed to determine if the Torg ratio was correlated with canal area, and if a "below normal" Torg ratio was predictive of LSS. RESULTS: The Torg ratio for 2SD below the mean was defined as 0.43 at L1, 0.43 at L2, 0.41 at L3, 0.38 at L4, 0.37 at L5. Regression analysis revealed a significant association of the Torg ratio with canal area (p < 0.01). A Torg ratio that was less than the mean - 2SD predicted canal stenosis at L2, L3, L4, and L5 (p < 0.01). Using a Torg ratio of <0.5 predicted stenosis with a sensitivity of 86% and specificity of 52% at all lumbar levels. CONCLUSIONS: Based on the results of our study, we have defined the lower limit of the normal Torg ratio at each level. A Torg ratio of <0.5 predicts LSS and could be a useful radiological tool for LSS screening.

Is congenital bony stenosis of the cervical spine associated with congenital bony stenosis of the thoracic spine? An anatomic study of 1072 human cadaveric specimens.

SUMMARY OF BACKGROUND DATA: Tandem stenosis of the cervical and lumbar spine is known to occur in 5% of individuals with symptomatic neural compression in one region. However, the prevalence of concurrent cervical and thoracic stenosis is not known. Whether this relationship is due to an increased risk of degenerative disease in these individuals, or whether this finding is due to the tandem presence of a congenitally small cervical and thoracic canal is unknown. OBJECTIVES: To determine the prevalence of concurrent thoracic and cervical stenosis and whether the presence of stenosis in the cervical spine is associated with stenosis in the thoracic spine. STUDY DESIGN: A morphoanatomic study of the cervical and thoracic cadaveric spines. METHODS: A total of 1072 adult skeletal specimens from the Hamann-Todd Collection in the Cleveland Museum of Natural History were selected. Canal area at each level was also calculated using a geometric formula. A standard distribution for each level was created, and values that were 2 SD below mean were considered as being congenitally stenotic. Linear regression analysis was used to determine the association between the additive canal areas at all levels in the cervical and thoracic spine and to determine the association between the number of stenotic levels in the cervical and thoracic spine. Logistic regression was used to calculate odds ratios for concurrent cervical and thoracic stenosis. RESULTS: The prevalence of concurrent cervical and thoracic stenosis is 1%. A positive association was found between the additive areas of all cervical and thoracic levels (P<0.01). No association, however, was found between the number of stenotic thoracic and cervical levels (P=0.689). Log regression demonstrated no significant association (odds ratio <1) between stenosis in the thoracic and cervical spine. CONCLUSIONS: The area changes in the cervical spine correlate with area variations in the thoracic spine and the severity of stenosis in the thoracic spine increases as the levels of stenosis increase in the cervical spine. The presence of tandem cervical and thoracic stenosis does seem to be, in part, related to the tandem presence of a congenitally small cervical and thoracic canal.

Correlation of slipped capital femoral epiphysis with disk degeneration.

SUMMARY OF BACKGROUND DATA: Spinal osteoarthritis is greater in patients with known hip pathology secondary to alterations in spinopelvic geometry. To our knowledge, no study has investigated the long-term impact of slipped capital femoral epiphysis (SCFE) on the spine. OBJECTIVE: To evaluate the relationship between SCFE and the presence of degenerative disk disease and facet arthrosis. STUDY DESIGN: An anatomic study of disk degeneration in cadaveric lumbar spines with SCFE. METHODS: An observational study was performed on 25 cadaveric specimens with SCFE and 647 controls that were identified out of 3100 total cadaveric specimens in an osteological collection. The specimens were evaluated for disk degeneration and facet arthrosis at L1/2 to L5/S1 using the classification of Eubanks and colleagues. Linear regression analyses were then used to determine the relationship between SCFE and lumbar disk and facet degeneration at each level, correcting for confounding factors such as age, sex, and race. RESULTS: Linear regression demonstrated a significant association (P<0.01) that was found between SCFE and degenerative disk disease at all levels from L1/2 to L5/S1. In addition, a significant association (P<0.01) was found between SCFE and facet arthrosis at all levels from L1/2 to L5/S1. CONCLUSIONS: The findings of this study show a relationship between SCFE and lumbar disk degeneration and facet arthrosis. This relationship may prove useful in predicting the course of spinal osteoarthritis in patients with SCFE.