Artificial Intelligence-Based Tool for Tumor Detection and Quantitative Tissue Analysis in Colorectal Specimens.

Digital pathology adoption allows for applying computational algorithms to routine pathology tasks. Our study aimed to develop a clinical-grade artificial intelligence (AI) tool for precise multiclass tissue segmentation in colorectal specimens (resections and biopsies) and clinically validate the tool for tumor detection in biopsy specimens. The training data set included 241 precisely manually annotated whole-slide images (WSIs) from multiple institutions. The algorithm was trained for semantic segmentation of 11 tissue classes with an additional module for biopsy WSI classification. Six case cohorts from 5 pathology departments (4 countries) were used for formal and clinical validation, digitized by 4 different scanning systems. The developed algorithm showed high precision of segmentation of different tissue classes in colorectal specimens with composite multiclass Dice score of up to 0.895 and pixel-wise tumor detection specificity and sensitivity of up to 0.958 and 0.987, respectively. In the clinical validation study on multiple external cohorts, the AI tool reached sensitivity of 1.0 and specificity of up to 0.969 for tumor detection in biopsy WSI. The AI tool analyzes most biopsy cases in less than 1 minute, allowing effective integration into clinical routine. We developed and extensively validated a highly accurate, clinical-grade tool for assistive diagnostic processing of colorectal specimens. This tool allows for quantitative deciphering of colorectal cancer tissue for development of prognostic and predictive biomarkers and personalization of oncologic care. This study is a foundation for a SemiCOL computational challenge. We open-source multiple manually annotated and weakly labeled test data sets, representing a significant contribution to the colorectal cancer computational pathology field.

Osseous Thoracic Foraminal Stenosis with Unilateral Congenital Absence of T1 Rib A Case Report.

A 43-year-old male with a congenital absence of his left T1 rib developed a left-sided T1-T2 spinal facet joint arthrosis and stenosis and clinical signs and symptoms of T1 radiculopathy. The patient was treated with a decompressive laminotomy and partial medial facetectomy resulting in immediate resolution of symptoms. This report should alert clinicians to consider this potential etiology when evaluating patients with thoracic radiculopathy.

Biologics and Minimally Invasive Approach to TLIFs: What Is the Risk of Radiculitis?

BACKGROUND: Bone morphogenetic protein (BMP) and allograft containing mesenchymal stem cells (live cell) are popular biologic substitutes for iliac crest autograft used in transforaminal lumbar interbody fusion (TLIF). Use of these agents in the pathogenesis of postoperative radiculitis remains controversial. Recent studies have independently linked minimally invasive (MIS) TLIF with increased radiculitis risk compared to open TLIF. The purpose of this study was to assess the rate of postoperative radiculitis in open and MIS TLIF patients along with its relationship to concurrent biologic adjuvant use. METHODS: Patients ≥18 years undergoing single-level TLIF from June 2012 to December 2018 with minimum 1-year follow-up were included. Outcome measures were rate of radiculitis, intra- and postoperative complications, revision surgery; length of stay (LOS), and estimated blood loss (EBL). RESULTS: There were 397 patients: 223 with open TLIFs, 174 with MIS TLIFs. One hundred and fifty-nine surgeries used bone morphogenetic protein (BMP), 26 live cell, 212 neither. Open TLIF: higher mean EBL, LOS, and Charlson Comorbidity Index (CCI) than MIS. Postoperative radiculitis in 37 patients (9.32% overall): 16 cases MIS BMP (15.69% of their cohort), 6 MIS without BMP (8.33%), 5 open BMP (8.77%), 10 open without BMP (6.02%). MIS TLIF versus open TLIF: no differences in 1-year reoperation rates, infection/wound complication, pseudarthrosis, or postoperative complication rate. BMP versus non-BMP: no differences in reoperation rates, infection/wound complication, pseudarthrosis, or postoperative complication rate. Multivariate logistic regression found that neither BMP (P = .109) nor MIS (P = .314) was an independent predictor for postoperative radiculitis when controlled for age, gender, body mass index, and CCI. Using paired open and MIS groups (N = 168 each) with propensity score matching, these variables were still not independently associated with radiculitis (P = .174 BMP, P = .398 MIS). However, the combination of MIS with BMP was associated with increased radiculitis risk in both the entire patient cohort (odds ratio [OR]: 2.259 [1.117-4.569], P = .023, N = 397) and PSM cohorts (OR: 2.196 [1.045-4.616], P = .038, N = 336) compared to other combinations of surgical approach and biologic use. CONCLUSION: Neither the MIS approach nor BMP use is an independent risk factor for post-TLIF radiculitis. However, risk of radiculitis significantly increases when they are used in tandem. This should be considered when selecting biological adjuvants for MIS TLIF. LEVEL OF EVIDENCE: 3.

MRI Radiological Predictors of Requiring Microscopic Lumbar Discectomy After Lumbar Disc Herniation.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To investigate radiological differences in lumbar disc herniations (herniated nucleus pulposus [HNP]) between patients receiving microscopic lumbar discectomy (MLD) and nonoperative patients. METHODS: Patients with primary treatment for an HNP at a single academic institution between November 2012 to March 2017 were divided into MLD and nonoperative treatment groups. Using magnetic resonance imaging (MRI), axial HNP area; axial canal area; HNP canal compromise; HNP cephalad/caudal migration and HNP MRI signal (black, gray, or mixed) were measured. T test and chi-square analyses compared differences in the groups, binary logistic regression analysis determined odds ratios (ORs), and decision tree analysis compared the cutoff values for risk factors. RESULTS: A total of 285 patients (78 MLD, 207 nonoperative) were included. Risk factors for MLD treatment included larger axial HNP area (P < .01, OR = 1.01), caudal migration, and migration magnitude (P < .05, OR = 1.90; P < .01, OR = 1.14), and gray HNP MRI signal (P < .01, OR = 5.42). Cutoff values for risks included axial HNP area (70.52 mm2, OR = 2.66, P < .01), HNP canal compromise (20.0%, OR = 3.29, P < .01), and cephalad/caudal migration (6.8 mm, OR = 2.43, P < .01). MLD risk for those with gray HNP MRI signal (67.6% alone) increased when combined with axial HNP area >70.52 mm2 (75.5%, P = .01) and HNP canal compromise >20.0% (71.1%, P = .05) cutoffs. MLD risk in patients with cephalad/caudal migration >6.8 mm (40.5% alone) increased when combined with axial HNP area and HNP canal compromise (52.4%, 50%; P < .01). CONCLUSION: Patients who underwent MLD treatment had significantly different axial HNP area, frequency of caudal migration, magnitude of cephalad/caudal migration, and disc herniation MRI signal compared to patients with nonoperative treatment.

Preoperative MRI predictors of health-related quality of life improvement after microscopic lumbar discectomy.

BACKGROUND: Lumbar herniated nucleus pulposus (HNP) is a common spinal pathology often treated by microscopic lumbar discectomy (MLD), though prior reports have not demonstrated which preoperative MRI factors may contribute to significant clinical improvement after MLD. PURPOSE: To analyze the MRI characteristics in patients with HNP that predict meaningful clinical improvement in health-related quality of life scores (HRQoL) after MLD. STUDY DESIGN/SETTING: Retrospective clinical and radiological study of patients undergoing MLD for HNP at a single institution over a 2-year period. PATIENT SAMPLE: Eighty-eight patients receiving MLD treatment for HNP. OUTCOME MEASURES: Cephalocaudal Canal Migration; Canal & HNP Anterior-Posterior (AP) Lengths and Ratio; Canal & HNP Axial Areas and Ratio; Hemi-Canal & Hemi-HNP Axial Areas and Ratio; Disc appearance (black, gray, or mixed); Baseline (BL); and 3-month (3M) postoperative HRQoL scores. METHODS: Patients >18 years old who received MLD for HNP with BL and 3M HRQoL scores of PROMIS (Physical Function, Pain Interference, and Pain Intensity), ODI, VAS Back, and VAS Leg scores were included. HNP and spinal canal measurements of cephalocaudal migration, AP length, area, hemi-area, and disc appearance were performed using T2 axial and sagittal MRI. HNP measurements were divided by corresponding canal measurements to calculate AP, Area, and Hemi-Area ratios. Using known minimal clinically important differences (MCID) for each ΔHRQoL score, patients were separated into two groups based on whether they reached MCID (MCID+) or did not reach MCID (MCID-). The MCID for PROMIS pain intensity was calculated using a decision tree. A linear regression illustrated correlations between PROMIS vs ODI and VAS Back/Leg scores. Independent t-tests and chi-squared tests were utilized to investigate significant differences in HNP measurements between the MCID+ and MCID- groups. RESULTS: There were 88 MLD patients included in the study (Age=44.6±14.9, 38.6% female). PROMIS pain interference and pain intensity were strongly correlated with ODI and VAS Back/Leg (R≥0.505), and physical function correlated with ODI and VAS Back/Leg (R=-0.349) (all p<.01). The strongest MRI predictors of meeting HRQoL MCID were gray disc appearance, HNP area (>116.6 mm2), and Hemi-Area Ratio (>51.8%). MCID+ patients were 2.7 times more likely to have a gray HNP MRI signal than a mixed or black HNP MRI signal in five out of six HRQoL score comparisons (p<.025). MCID+ patients had larger HNP areas than MCID- patients had in five out of six HRQoL score comparisons (116.6 mm2±46.4 vs 90.0 mm2±43.2, p<.04). MCID+ patients had a greater Hemi-Area Ratio than MCID- patients had in four out of six HRQoL score comparisons (51.8%±14.7 vs 43.9%±14.9, p<.05). CONCLUSIONS: Patients who met MCID after MLD had larger HNP areas and larger Hemi-HNP Areas than those who did not meet MCID. These patients were also 2.7× more likely to have a gray MRI signal than a mixed or black MRI signal. When accounting for HNP area relative to canal area, patients who met MCID had greater Hemi-HNP canal occupation than patients who did not meet MCID. The results of this study suggest that preoperative MRI parameters can be useful in predicting patient-reported improvement after MLD.

Patients at the Highest Risk for Reherniation Following Lumbar Discectomy in a Multicenter Randomized Controlled Trial.

BACKGROUND: The purposes of the present study were to (1) confirm the risk of recurrent lumbar disc herniation in patients with a large anular defect who had undergone limited discectomy and (2) assess potential risk factors within this population. METHODS: The patient population was extracted from the control cohort of a prospective, randomized, multicenter controlled trial investigating the efficacy of an anular closure device following standard limited discectomy. All control patients underwent limited discectomy for the treatment of a single-level symptomatic posterior or posterolateral lumbar disc herniation. Only patients presenting with a large anular defect (6 to 10 mm wide by 4 to 6 mm long) were included in the study (n = 278). Baseline demographic, clinical, and surgical characteristics were recorded. Follow-up evaluations were performed at 6 weeks and at 3, 6, 12, and 24 months. Imaging modalities included magnetic resonance imaging, low-dose computed tomography, and radiographs. Symptomatic recurrent lumbar disc herniation was defined as any symptomatic postoperative herniation on either side of the index level. A multivariate logistic regression analysis of demographic and surgical variables associated with the incidence of recurrent lumbar disc herniation was performed. RESULTS: The mean anular defect area (and standard deviation) was 39.3 ± 9.1 mm2, and the mean excised nuclear tissue volume was 1.3 ± 0.8 mL. At 2 years, the incidence of symptomatic recurrent lumbar disc herniation was 25.3% (64 of 253), with the herniation occurring at a mean of 264 days after the index procedure. Of the 64 patients with recurrent lumbar disc herniation, 36 underwent a subsequent surgical procedure. Logistic regression analysis identified an increased risk for recurrent lumbar disc herniation in females (odds ratio, 2.2) and in patients with greater anular defect widths (odds ratio, 1.3). Furthermore, multivariate logistic regression analyses revealed a significant interaction between age and sex (p = 0.005). CONCLUSIONS: The outcomes of the present study provide the most substantial evidence to date in confirming previous reports of a high risk of reherniation among patients with large anular defects. Among those with large anular defects (width, ≥6 mm), females ≤50 years of age had the highest risk (up to ∼10 times higher) of recurrent lumbar disc herniation. It is recommended that an anular repair or closure should be performed after limited discectomies in patients with large anular defects. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Implantation of a bone-anchored annular closure device in conjunction with tubular minimally invasive discectomy for lumbar disc herniation: a retrospective study.

BACKGROUND: Minimally invasive techniques for lumbar discectomy have been recommended as superior to open techniques due to lower blood loss, lower rates of infection and shorter recovery. There are, however, concerns that this approach does not sufficiently remove the herniated nuclear material, thus leaving the patient susceptible to reherniation requiring reoperation. The purpose of this study was to examine the safety and viability of an annular closure device in limiting reherniation and reoperation in a cohort of patients undergoing minimally invasive lumbar discectomy with the assistance of an annular closure device. METHODS: We retrospectively analysed the results from patients treated by a single surgeon between March 2011 and December 2017. All patients had been diagnosed with a large (≥ 5 mm) defect and were treated via minimally invasive surgical techniques. Outcomes included demographic data, the procedural duration and the rates of symptomatic reherniation and reoperation. RESULTS: 60 patients were included in the study. The mean age was 42 years (range: 19-66); mean BMI was 24.1 (range: 16.7-36.3). Mean surgical duration was 29 min (range: 16-50). Reoperation was required in 5% (3/60) of patients, although only 3% (2/60) experienced symptomatic reherniation at the index level. No other complications were reported. CONCLUSIONS: In our study, the use of an annular closure device during minimally invasive lumbar discectomy in a population of patients with large herniations was associated with low rates of reherniation and reoperation at the index level. While more research is required, the results of this study demonstrate the safety and viability of the annular closure device as an adjunct to minimally invasive discectomy.

The facet joint loading profile of a cervical intervertebral disc replacement incorporating a novel saddle-shaped articulation.

STUDY DESIGN: Biomechanical study. OBJECTIVE: To evaluate the cervical facet loading profile of an intervertebral cervical disc prosthesis incorporating a unique saddle-shaped articulation and to determine the effect of implantation of the prosthesis on both the loading curve and area distribution of facet loading, when compared with that of an intact specimen. SUMMARY OF BACKGROUND DATA: This is the first study that examines the effect of implantation of a cervical disc replacement on the loading of the facet joints. METHODS: Fresh-frozen ovine cervical spine specimens were used. Specimens were prepared and disarticulated to yield 6 functional spinal units, which were secured and mounted in a custom fixture on a material testing apparatus. A novel pressure sensor was constructed by combining a resistive ink thin film sensor with Fuji pressure-sensitive film. The sensor was calibrated before unilateral insertion into the cervical facet joint via a small arthrotomy. Specimens were tested in both intact condition and after surgical intervention consisting of discectomy and implantation of an intervertebral cervical disc prosthesis (CerviCore, Stryker Spine, Allendale, NJ). Specimens were tested in flexion, extension, and lateral bending to 3 Nm and in torsion to 2.5 Nm. At the termination of each loading profile, the load was maintained for 30 seconds to permit full exposure of the Fuji film. For each configuration, the maximum resultant load, load rate, and contact area pressure at the endpoint of the loading profile were determined. A paired Student t test was used to determine the differences between the intact specimen and the specimen with an implanted intervertebral disc prosthesis. RESULTS: There were no statistically significant differences in mean or maximum pressures between the intact specimen and the specimen with an intervertebral disc in all loading configurations. Similarly, there was no significant difference in the total measured force between the groups in all loading configurations. There was no significant difference in contact areas between the groups in flexion, lateral bending, and torsion. When evaluated in extension, the intact specimen had a mean contact area of 0.8 cm compared with 0.5 cm for the intervertebral disc (P<0.02). CONCLUSIONS: Biomechanical testing in an ovine model demonstrated no significant difference in measured facet pressures and forces between an intact native cervical disc specimen and a cervical intervertebral disc prosthesis using a saddle-shaped articulation. Peak and mean pressures were not demonstrated to be significantly different between the implanted and intact disc conditions. Implantation of the prosthesis resulted in a significant reduction of contact area under extension moments.

The manubrium as an external guide for centralizing anterior cervical plates: technique tips and initial experience.

STUDY DESIGN: Technique tips and retrospective review of prospectively collected data. OBJECTIVE: To describe a technique for centralizing cervical plates using the center of the manubrium as a primary external guide and its alignment with the mandible as a secondary guide. SUMMARY OF BACKGROUND DATA: Proper alignment of cervical plates is desirable to avoid improper placement of screws and possibly altered biomechanical performance. Large body habitus may portend suboptimal exposure, a limited utility of skin surface landmarks for level determination, and may make it difficult to reliably centralize plates in the coronal plane during anterior cervical surgery. METHODS: We describe a technique that uses the center of the manubrium to determine the midline of the cervical spine and align a line drawn through the manubrium with the center of the mandible to provide a central axis for placing cervical plates along the entire cervical spine. We used anteroposterior fluoroscopy to validate that a line from the middle of the manubrium to the mandible bisected the spinous processes and midline of the vertebral bodies. We prospectively collected data on 39 consecutive patients undergoing anterior cervical discectomy and fusion with cervical plates using this technique. RESULTS: The mean amount of angulation and translation about a midline axis were 2.24 degrees +/- 1.49 degrees and 1.04 +/- 0.86 mm, respectively. There were no statistical differences among 1-level, 2-level, and 3-level fusions (P > 0.05). The intraobserver correlation coefficient for the measurement technique was R = 0.90 (P = 0.0016). CONCLUSION: We validated that the midline of the cervical spine is in line with a straight bovie cord connecting the midline of the manubrium to the midline of the mandible using anteroposterior fluoroscopy. Using this line, we prospectively centered cervical plates with no significant difference between levels. These data may also serve as a benchmark for assessing cervical plate alignment.

The reliability of computed tomography and magnetic resonance imaging grading of lumbar facet arthropathy in total disc replacement patients.

STUDY DESIGN: Prospective inter-rater and intrarater reliability analysis. OBJECTIVE: To compare the inter-rater and intrarater reliability of magnetic resonance imaging (MRI) and computed tomography (CT) for grading of facet arthropathy as well as determining whether there is a contraindication to total disc replacement (TDR). SUMMARY OF BACKGROUND DATA: Several classifications attempted to evaluate lumbar facet joints and their degree of arthropathy. The Fujiwara-MRI and Pathrea-CT classifications remain the most commonly used. METHODS: A total of 10 fellowship-trained orthopedic spine surgeons and 3 orthopedic spine fellows evaluated 50 levels from L3-L4 through L5-S1 on parallel axial MRI (T1 and T2) and CT images. The degree of osteoarthritis was graded on a 4-point scale (Fujiwara-MRI and Pathrea-CT). Surgeons evaluated whether the degree of facet disease represented a contraindication to TDR. Grading was performed during 2 sessions. Weighted kappa statistics were used to describe inter- and intraobserver agreement. RESULTS: The inter-rater reliability for MRI was 0.21 and 0.07 (fair to slight) among attendings and fellows, respectively. inter-rater reliability for CT was 0.33 and 0.27 (fair), respectively. The mean intrarater reliability for MRI was fair, 0.36 (attendings) and 0.26 (fellows). The mean intrarater reliability for CT was moderate, 0.52 (attendings) and 0.51 (fellows). For possible TDR contraindication, the inter-rater reliability for MRI was 0.22 and 0.01 (fair to slight) among attendings and fellows, respectively. Inter-rater reliability for CT was 0.33 and 0.45 (fair), respectively. The mean intrarater reliability for MRI was fair, 0.36 (attendings) and 0.26 (fellows). The mean intrarater reliability for CT was moderate, 0.52 (attendings) and 0.51 (fellows). CONCLUSION: The current grading system for facet arthropathy has only fair agreement. CT is slightly more reliable for grading. Intrarater reliability was only fair for MRI and moderate for CT. Only limited agreement existed between surgeons as to the extent of facet disease that would pose as a contraindication for TDR.

Complete and incomplete femoral stress fractures in the adolescent athlete.

Stress fractures of the lower extremities are a known risk of intense physical activity. Femoral stress fractures represent a small subset of lower extremity stress fractures but can have grave consequences if undetected, resulting in a displaced fracture. If detected prior to displacement, conservative treatment of these fractures is highly successful. However, displacement frequently makes surgical treatment necessary. Unfortunately these fractures are often difficult to detect. Symptoms of stress fractures are frequently vague, particularly in femoral stress fractures. Specific physical examination techniques can assist in diagnosis but require a very high index of suspicion. Plain radiographs are also frequently negative in early stress fractures, further confounding diagnosis, and bone scan or magnetic resonance imaging studies are frequently needed. We present a case of an otherwise healthy 15-year-old male athlete with bilateral femoral stress fractures. The patient reported bilateral knee pain of 2 months' duration with physical activity, but had not curtailed his activities. His pain had been evaluated with plain radiographs, which were interpreted as normal. Immediately prior to presentation, while playing lacrosse, he sustained a displaced right supracondylar femur fracture. On further evaluation with bone scan he was found to have a contralateral nondisplaced supracondylar femoral stress fracture. His displaced fracture was managed with a retrograde intramedullary nail and his nondisplaced fracture was treated conservatively.

Early failure of lumbar disc replacement: case report and review of the literature.

We report a case of a patient who underwent two-level lumbar total disc replacement at L4-L5 and L5-S1 with the ProDisc II prosthesis, who was diagnosed with early anterior migration of the caudally placed device with partial occlusion of the left common iliac vein. The device was explanted and revised to an anterior lumbar interbody fusion with posterior instrumented fusion. Despite the substantial experience with lumbar disc arthroplasty in Europe and the United States, there exist few reports of device explantation or revision. To our knowledge, early postoperative vascular complications, while discussed hypothetically, have not been reported. With implantation of the total disc replacement in proximity to the great vessels, the potential for vascular complications is clearly substantial. The technical aspects of the device explantation are discussed as well as issues pertinent to early failure. A literature review of device complications associated with lumbar total disc replacement is also presented.

Anterior cervical decompression and fusion with plate fixation as an outpatient procedure.

BACKGROUND CONTEXT: Outpatient cervical spine surgery has previously been described for posterior laminoforaminotomy and anterior microdiscectomy with allograft fusion. Anterior cervical discectomy and fusion (ACDF) with plate fixation has not, to our knowledge, been described as an outpatient procedure. PURPOSE: The objective of this study was to evaluate the safety and feasibility of ACDF with instrumentation when performed as an outpatient in a free-standing ambulatory surgical center. Additionally, the authors sought to determine any patient selection bias and its effect on outcome. STUDY DESIGN: This study is a retrospective medical record review. PATIENT SAMPLE: The sample included all patients who underwent one or two level ACDF with plate fixation at levels C4-5 or below as an adjunct to autogenous iliac crest bone graft or structural allograft from 1998 to 2002 by the two senior authors. OUTCOME MEASURES: Complications were assessed clinically with special attention to dysphagia and respiratory complications. Inpatient lengths of stay and postoperative hospital admission or readmission were also measured. METHODS: Thirty consecutive patients were treated at a free-standing ambulatory surgery center, whereas two control groups, each of 30 consecutive patients, had surgery performed in the hospital and were admitted overnight for observation. The first control group consisted of admitted patients before the commencement of patient selection for the outpatient group; the second control group was comprised of admitted patients who had surgery performed concurrently with the outpatient group. The study group was evaluated on the first postoperative day and 3 weeks after surgery. RESULTS: Ninety patients underwent ACDF plate fixation at 140 different levels. Forty patients were treated at one level, and 50 were treated at two levels. The three groups were comparable in age, sex, and body mass index. There were no major complications. Seven patients (13%) had minor postoperative complications among the controls: transient dysphagia in three (5%) and graft donor site pain in four (14%). Three patients (10%) in the outpatient group had minor complications (all had dysphagia). Among the controls, four patients (7%) had increased length of stay owing to complications. Four patients (7%) in the combined control group were readmitted for early complications; no patient was admitted for a complication after outpatient surgery. CONCLUSIONS: In the present study, selection criteria for outpatient surgery included one or two level involvement C4-5 or lower, absence of myelopathy, subjective neck size, and estimated operative time. The data did not otherwise suggest a difference in the surgical populations. The outpatient group had a lower complication rate compared with the controls. This was likely the result of selection bias. Transient dysphagia was the most prevalent complication in the outpatient group.

Manifestations of hereditary multiple exostoses.

The solitary osteochondroma, a common pediatric bone tumor, is a cartilage-capped exostosis. Hereditary multiple exostosis is an autosomal dominant disorder manifested by the presence of multiple osteochondromas. Linkage analysis has implicated mutations in the EXT gene family, resulting in an error in the regulation of normal chondrocyte proliferation and maturation that leads to abnormal bone growth. Although exostoses are benign lesions, they are often associated with characteristic progressive skeletal deformities and may cause clinical symptoms. The most common deformities include short stature, limb-length discrepancies, valgus deformities of the knee and ankle, asymmetry of the pectoral and pelvic girdles, bowing of the radius with ulnar deviation of the wrist, and subluxation of the radiocapitellar joint. For certain deformities, surgery can prevent progression and provide correction. Patients with hereditary multiple exostosis have a slight risk of sarcomatous transformation of the cartilaginous portion of the exostosis.

Intradiscal pressure monitoring in the cervical spine.

BACKGROUND: Discography has been widely used in the lumbar and cervical spine as a diagnostic tool to identify sources of discogenic pain that may be amenable to surgical treatment. Discography in the cervical spine is currently performed without the benefit of pressure monitoring, and corresponding pressure parameters have not been determined. OBJECTIVE: The purpose of this study was to develop the framework for intradiscal pressure monitoring in the cervical spine and the basis for a pressure curve that will reflect clinically significant cervical internal disc disruption. We also sought to determine whether there is any pressure increase in adjacent discs during cervical discography that might result in false-positive diagnosis during in-vivo discography. An additional goal was to establish safe upper parameters for infusion volume and intradiscal pressure in the cervical spine. DESIGN: Investigation of fresh-frozen discs in the cervical spine. METHODS: Investigated were 26 discs in 5 fresh-frozen cadaveric cervical spines aged 45 to 68 with no prior history of cervical spine disease. A T2 MRI was performed on each specimen and radiographically abnormal discs were noted. Pressure-controlled, fluoroscopically guided discography was performed on each level using a right lateral approach. Opening pressure, rupture pressure, volume infused, and location of rupture were recorded. Pressures were simultaneously recorded at each adjacent disc level using additional pressure monitors and identical needle placement. Immediately following discography, CT was performed on each specimen according to the discography protocol. RESULTS: Twenty-six discs C2-3 to C7-T1 were grossly intact for evaluation. The median opening pressure was 30 psi (range 14-101 psi). Two discs did not rupture and were pressurized to 367 psi. In 24 discs, the median intradiscal rupture pressure was 40 psi (range 14-171 psi). The median volume infused at rupture was 0.5 ml (range 0.25-1.0 ml). When grouped, the median intradiscal rupture pressure in the C2-3, C3-4, and C7-T1 discs was 53 psi (range 16-171 psi) compared to 36.5 psi (range 14-150 psi) in the C4-5, C5-6, and C6-7 discs (p=0.18). There was no measurable pressure change in any of the 30 adjacent disc levels evaluated. CONCLUSION: In the cervical spine, iatrogenic disc injury may be caused at significantly lower pressures and volumes infused than in the lumbar spine. There was no measurable pressure change in any of the adjacent disc levels evaluated at maximum intradiscal pressurization. Further cadaveric testing will be necessary to develop parameters for intradiscal pressure monitoring in the cervical spine.