Acetabular Component Removal Systems.

¼: As primary total hip arthroplasty procedures continue to rise, acetabular revision surgery will be in increasing demand. ¼: Treatment of acetabular component failure and associated bone defects depends on patient characteristics, the degree and location of bone loss, the ability of the columns to support biologic fixation, and the presence of pelvic discontinuity. ¼: In revision total hip arthroplasty, technological advances have been made to address limitations of acetabular cup removal while preserving host bone stock. ¼: The goal of acetabular revision reconstruction should be to obtain stable fixation and restore the hip center. The various acetabular cup removal systems are discussed.

An Anatomic Study Examining Lumbar Pars Interarticularis Distance and Spinal Canal Width in Relation to Lumbar Decompressive Surgery.

BACKGROUND: Lumbar laminectomy is a surgical procedure allowing for decompression of neural structures. A wide laminectomy to adequately decompress neural elements without compromising the structural integrity of the spinal column is ideal. Pars interarticularis fractures with spinal instability after isolated laminectomy from overresection of the posterior elements have been reported. There are limited anatomical studies in the spine literature that measure the pars interarticularis distance (PID) and spinal canal width (SCW) in the lumbar spine. OBJECTIVE: The purpose of this study was to assess the differences in PID and SCW at each level of the lumbar spine and to determine their effects on the extent of laminectomy at each lumbar level. METHODS: We performed an anatomic study measuring PID and SCW in the lumbar spine from 93 skeletally matured osseous specimens. Groups were compared using an independent sample t test, 1-way analysis of variance, and Wilcoxon test, and significance was set at P < 0.05. RESULTS: Our study suggests that the distance between PID and SCW increases from L1 to L5 in African American and Caucasian women and men. However, the respective increase in SCW at each lumbar level is less than the respective increase in PID at the same levels. This trend suggests that there is a wider window available for decompression without compromising spinal stability in the lower lumbar spine compared with the upper lumbar spine. CONCLUSIONS: Our findings suggest that the upper lumbar spine has a narrower window for decompression; therefore, care should be taken to preserve as much of the pars at L1-L3. Understanding the variations in PID and SCW in the lumbar spine will help surgeons perform adequate decompression of a stenotic canal while avoiding postoperative spinal instability. CLINICAL RELEVANCE: Awareness of PID to SCW ratio may help spine surgeons avoid iatrogenic instability, postoperative intractable back pain, spondylolisthesis, or complications involving alterations of the lumbar spine biomechanics.

Critical analysis of the evaluation of postoperative dysphagia following an anterior cervical discectomy and fusion.

BACKGROUND AND PURPOSE: Postoperative dysphagia is a known complication of anterior cervical discectomy and fusion (ACDF) with reported incidences ranging from 1 to 79%. No standardized guidelines exist for spine surgeons to evaluate postoperative dysphagia after ACDF. A systematic method may be beneficial in distinguishing transient postoperative dysphagia secondary to intubation from those with postoperative complications. This study evaluates the causes, recognition, and clinical evaluation of postoperative dysphagia following ACDF. METHODS: International classification of disease (ICD) and current procedural terminology (CPT) codes were used to identify ACDF patients and compared to anterior lumbar discectomy and fusion (ALDF), serving as a control group, between the years 2015-2019 and those diagnosed with dysphagia within 1 year. Demographics, operative details, and clinical evaluation were reviewed. Exclusion criteria included history of head and neck procedures, cancer, stroke, radiation, and trauma. RESULTS: One hundred thirty-one ACDF and 93 ALDF patients met inclusion criteria. Twenty-seven (20.6%) ACDF patients were diagnosed with dysphagia within 1 year. Less than half of the dysphagia patients had the word "dysphagia" documented in their 1-month spine surgeon follow up visit. Only 66% of dysphagia patients had specialist evaluation and one third of those patients were referred by their surgeon. Only six patients received diagnostic barium swallow evaluations. CONCLUSION: Postoperative dysphagia risk increases in ACDF compared to ALDF, likely due to underlying anatomy. Postoperative dysphagia symptoms are not effectively documented by spine surgeons and as a result underevaluated by dysphagia specialists. Patients may benefit from more extensive pre- and post-operative screening, evaluation, and referral regarding dysphagia symptoms following ACDF.

Single-Site Retrospective Assessment of Surgical Outcomes in Non-Ambulatory Patients with Degenerative Cervical Myelopathy.

STUDY DESIGN: A retrospective study of surgical outcomes in patients with degenerative cervical myelopathy (DCM). OBJECTIVE: To better characterize outcomes following cervical decompression in those with severe, non-ambulatory forms of DCM. SUMMARY OF BACKGROUND DATA: DCM represents a collection of age-related degenerative processes of the cervical spine that can result in motor, sensory, and autonomic dysfunction, leading to significant reductions in quality of life. Individuals with severe, non-ambulatory forms of DCM are often treated with spinal decompression although the extent of neurological improvement for this patient population is unclear. METHODS: A retrospective analysis of 48 non-consecutive non-ambulatory patients who underwent cervical decompression surgery between January 2007 and December 2018. Paired t tests and Wilcoxon signed rank tests were used to compare Nurick grade and modified Japanese Orthopedic Association (mJOA) score before and after surgery. Patient demographics, operative details, and postsurgical complications were analyzed using descriptive statistics. RESULTS: Patients experienced significant improvements in both Nurick grade and mJOA score following cervical decompression surgery. The mean Nurick grade improved from 4.10 ±â€Š0.31 to 2.21 ±â€Š0.82 (P < 0.001, paired t test; 95% confidence interval [CI] -2.08 to -1.71), while the mean mJOA score improved from 10.58 ±â€Š1.51 to 13.60 ±â€Š1.58 (P < 0.001, paired t test; 95% CI 2.59-3.45). The average follow-up duration was 2.50 ±â€Š1.83 years. Following surgery, 44 of the 48 patients in the study gained the ability to ambulate without the aid of a walking frame or someone else's assistance. CONCLUSION: This study demonstrated that patients with severe forms of DCM experienced significant improvement in neurological function following cervical decompression surgery. These improvements indicate that cervical decompression surgery is effective in this patient population and has the potential to improve neurological status.Level of Evidence: 3.

Complications of a Unilateral Nondisplaced Cervical Facet Fracture in a Patient With Previously Noninstrumented Anterior Cervical Fusion.

Fused motion segments have been documented to alter the biomechanics of the cervical spine and compromise its stability. Current literature describes a growing association between the presence of prior noninstrumented fused cervical segments and the predisposition to acute, traumatic instability at adjacent levels. We present the case of a stable cervical spine fracture pattern in a patient with a history of multilevel noninstrumented anterior cervical spine fusion-initially presenting as a small, nondisplaced unilateral facet fracture that ultimately progressed to overt displacement with kyphosis resulting in acute cervical pain and instability. The patient underwent urgent open reduction and instrumented posterior fixation. We discuss the challenges associated with a timely diagnosis and offer insight into the surgical management of this rare yet potentially catastrophic complication.

Unilateral tubular approach for bilateral laminotomy: effect on ipsilateral and contralateral buttock and leg pain.

PURPOSE: Tubular laminotomy is an effective procedure for treatment of lumbar spinal stenosis (LSS) and lateral recesses stenosis. Most surgeons familiar with the procedure agree that the tubular approach appears to afford a more complete decompression of the contralateral thecal sac and nerve root, as compared to the ipsilateral approach. With this study we sought to answer the question whether this is reflected in clinically significant differences between the ipsilateral and contralateral side pain improvements. METHODS: In a retrospective case study, patients with LSS and lateral recesses stenosis who started out with VAS scores that were similar on the right and left side were included. All patients underwent a tubular (MIS) "over the top" laminotomy from a unilateral approach and through one incision. Surgeries were performed by a single surgeon in a single center. At the last follow-up, the extent of VAS score improvement on the approach (ipsilateral) side was compared to that of the contralateral side. RESULTS: Thirty-three patients were included in. At the latest follow-up of 25.8 ± 3.4 months, there were statistically significant improvements in ODI and back VAS scores (p = 0.002 and p < 0.0001, respectively). In addition, buttock VAS scores were significantly improved both on the ipsilateral and the contralateral side (p < 0.001, and p = 0.001, respectively). Similarly, leg VAS scores were improved significantly on both sides (p < 0.001, and p = 0.001, respectively). There were no statistically significant differences between the extent of pain improvement on the ipsilateral and the contralateral side. CONCLUSIONS: MIS tubular laminotomy through a unilateral approach results in clinically effective bilateral decompression of LSS and lateral recesses, regardless of the approach side.

Radiographic and Clinical Outcome of Silicate-substituted Calcium Phosphate (Si-CaP) Ceramic Bone Graft in Spinal Fusion Procedures.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To evaluate the radiographic and clinical outcome of silicate-substituted calcium phosphate (Si-CaP), utilized as a graft substance in spinal fusion procedures. SUMMARY OF BACKGROUND DATA: Specific properties of Si-CaP provide the graft with negative surface charge that can result in a positive effect on the osteoblast activity and neovascularization of the bone. METHODS: This study included those patients who underwent spinal fusion procedures between 2007 and 2011 in which Si-CaP was used as the only bone graft substance. Fusion was evaluated on follow-up CT scans. Clinical outcome was assessed using Oswestry Disability Index, Neck Disability Index, and the visual analogue scale (VAS) for back, leg, neck, and arm pain. RESULTS: A total of 234 patients (516 spinal fusion levels) were studied. Surgical procedures consisted of 57 transforaminal lumbar interbody fusion, 49 anterior cervical discectomy and fusion, 44 extreme lateral interbody fusion, 30 posterior cervical fusions, 19 thoracic fusion surgeries, 17 axial lumbar interbody fusions, 16 combined anterior and posterior cervical fusions, and 2 anterior lumbar interbody fusion. At a mean radiographic follow-up of 14.2±4.3 months, fusion was found to be present in 82.9% of patients and 86.8% of levels. The highest fusion rate was observed in the cervical region. At the latest clinical follow-up of 21.7±14.2 months, all clinical outcome parameters showed significant improvement. The Oswestry Disability Index improved from 45.6 to 13.3 points, Neck Disability Index from 40.6 to 29.3, VAS back from 6.1 to 3.5, VAS leg from 5.6 to 2.4, VAS neck from 4.7 to 2.7, and VAS arm from 4.1 to 1.7. Of 7 cases with secondary surgical procedure at the index level, the indication for surgery was nonunion in 3 patients. CONCLUSIONS: Si-CaP is an effective bone graft substitute. At the latest follow-up, favorable radiographic and clinical outcome was observed in the majority of patients. LEVEL OF EVIDENCE: Level-III.

Correction: Minimally Invasive 2D Navigation-Assisted Treatment of Thoracolumbar Spinal Fractures in East Africa: A Case Report.

[This corrects the article DOI: 10.7759/cureus.507.].

Anterior Cervical Discectomy and Fusion (ACDF): Comparison Between Zero Profile Implants and Anterior Cervical Plate and Spacer.

INTRODUCTION: Interposition grafts combined with anterior plating currently remain the gold standard for anterior cervical discectomy and fusion. The use of anterior plates increases fusion rates but may be associated with higher rates of postoperative dysphagia. The aim of the current study was to determine the clinical and radiological outcomes following anterior cervical discectomy and fusion (ACDF) using zero-profile anchored spacers versus standard interposition grafts with anterior plating. METHODS: This was a retrospective case series. A total of 53 male and 51 female consecutive patients (164 total operated levels) who underwent ACDF between 2007 and 2011 were included. The mean clinical follow-up was 15.7 ± 1.2 (SEM) months for patients with zero-profile implants and 14.8 ± 2.1 months for patients with conventional ACDF with anterior plating. Patient demographics, operative details, clinical outcomes, complications, and radiographic imaging were reviewed. Dysphagia was determined using the Bazaz criteria. RESULTS: Clinical outcome scores improved in both groups as measured by the modified Japanese Orthopedic Association and Nurick scores. Zero-profile constructs gave rise to significantly less prevertebral soft tissue swelling compared to constructs with anterior plates postoperatively (15.74 ± 0.52 as compared to 20.48 ± 0.85 mm, p < 0.001) and at the latest follow-up (10.88 ± 0.39 mm vs. 13.72 ± 0.67 mm, p < 0.001). There was a significant difference in the incidence of dysphagia at the latest follow-up (1.5% vs. 20%, p=0.001, zero-profile vs. anterior plate, respectively). CONCLUSION: Zero-profile implants lead to functional outcomes similar to standard anterior plate constructs. Avoiding the use of an anterior locking plate may decrease the risk of persistent postoperative dysphagia.

Minimally Invasive 2D Navigation-Assisted Treatment of Thoracolumbar Spinal Fractures in East Africa: A Case Report.

Spinal surgery under Eastern-African circumstances is technically demanding and associated with significant complications, such as blood loss, infection, and wound breakdown. We report a spinal trauma case that was performed using minimally invasive surgery (MIS) and navigation, and hypothesize that these newer techniques may enable surgeons to perform effective spinal surgery with minimal complications and good outcomes.  During the 2014 First Hands-on Neurotrauma Course held in Dar es Salaam, Tanzania, we successfully performed three minimally invasive and two-dimensional (2D) navigated spinal surgeries to decompress and stabilize patients with complete and incomplete spinal injuries. In this report, we present a case of a paraplegic patient with a T12 burst fracture who tolerated MIS surgery with no intraoperative complications, and is doing well with no postoperative complications one year after surgery. Minimally invasive spinal surgery and 2D navigation may offer advantages in resource-poor countries. As part of the Weill Cornell Tanzania Neurosurgery project and in conjunction with the Foundation for International Education in Neurological Surgery (as well as other organizations), further experiences with 2D navigation and MIS surgery will be recorded in 2015. A neurotrauma registry has already been implemented to better understand the current management of neurotrauma in Eastern Africa.

Radiation-Induced Necrosis of the Temporal Bone: Diagnosis and Management.

OBJECTIVE: To document our experience with osteoradionecrosis (ORN) of the temporal bone. STUDY DESIGN: Retrospective case review. SETTING: Tertiary care medical center. PATIENTS: Patients who developed exposed necrotic bone of the external auditory canal after radiation therapy to the head and neck. INTERVENTIONS: Temporal bone ORN was managed conservatively in all patients with a combination of systemic antibiotics, antibiotic ear drops, and in-office debridement. Three patients required surgery, two of which were for a cholesteatoma. MAIN OUTCOME MEASURE: The need for surgical intervention in the management of ORN. RESULTS: Twenty-three patients with ORN of the temporal bone comprise the study group. The average age of patients at the time of diagnosis was 58 years (range, 34-75 yr). The parotid gland was the most common primary tumor site (n = 10). The mean lag time from completion of radiotherapy to diagnosis of ORN was 11 years (range, 2-48 yr). The most common presenting symptom was hearing loss (n = 18), followed by tinnitus (n = 13) and otorrhea (n = 13). All 23 patients were managed conservatively with antibiotic therapy and in-office debridement of necrotic bone. None of the patients required temporal bone resection and/or free-flap reconstruction. CONCLUSION: ORN of the temporal bone is a rare adverse event that can occur after radiotherapy for a variety of neoplasms of the head, neck, and central nervous system. Conservative management, which includes directed antibiotic therapy and regular in-office debridement of necrotic bone, can adequately control the disease process and symptomatology, thus avoiding more invasive surgical interventions.

Expandable Polyaryl-Ether-Ether-Ketone Spacers for Interbody Distraction in the Lumbar Spine.

Study Design Retrospective case series. Objective StaXx XD (Spine Wave, Inc., Shelton, CT, United States) is an expandable polyaryl-ether-ether-ketone (PEEK) wafer implant utilized in the treatment of lumbar degenerative disease. PEEK implants have been successfully used as interbody devices. Few studies have focused on expandable PEEK devices. The aim of the current study is to determine the radiographic and clinical outcome of expandable PEEK cages utilized for transforaminal lumbar interbody fusion in patients with lumbar degenerative diseases. Methods Forty-nine patients who underwent lumbar interbody fusion with implantation of expandable PEEK cages and posterior instrumentation were included. The clinical outcome was evaluated using the visual analog scale (VAS) and the Oswestry Disability Index (ODI). Radiographic parameters including disk height, foraminal height, listhesis, local disk angle of the index level/levels, regional lumbar lordosis, and graft subsidence were measured preoperatively, postoperatively, and at latest follow-up. Results At an average follow-up of 19.3 months, the minimum clinically important difference for the ODI and VAS back, buttock, and leg were achieved in 64, 52, 58, and 52% of the patients, respectively. There was statistically significant improvement in VAS back (6.42 versus 3.11, p < 0.001), VAS buttock (4.66 versus 1.97, p = 0.002), VAS leg (4.55 versus 1.96, p < 0.001), and ODI (21.7 versus 12.1, p < 0.001) scores. There was a significant increase in the average disk height (6.49 versus 8.18 mm, p = 0.037) and foraminal height (15.6 versus 18.53 mm, p = 0.0001), and a significant reduction in the listhesis (5.13 versus 3.15 mm, p = 0.005). The subsidence of 0.66 mm (7.4%) observed at the latest follow-up was not significant (p = 0.35). Conclusions Midterm results indicate that expandable PEEK spacers can effectively and durably restore disk and foraminal height and improve the outcome without significant subsidence.

Endoscopic lumbar foraminotomy.

Foraminal stenosis frequently causes radiculopathy in lumbar degenerative spondylosis. Endoscopic transforaminal techniques allow for foraminal access with minimal tissue disruption. However, the effectiveness of foraminal decompression by endoscopic techniques has yet to be studied. We evaluate radiographic outcome of endoscopic transforaminal foraminotomies performed at L3-L4, L4-L5, and L5-S1 on cadaveric specimens. Before and after the procedures, three dimensional CT scans were obtained to measure foraminal height and area. Following the foraminotomies, complete laminectomies and facetectomies were performed to assess for dural tears or nerve root damage. L3-L4 preoperative foraminal height increased by 8.9%, from 2.12±0.13cm to 2.27±0.14cm (p<0.01), and foraminal area increased by 24.8% from 2.21±0.18cm(2) to 2.72±0.19cm(2) (p<0.01). At L4-L5, preoperative foraminal height was 1.87±0.17cm and area was 1.78±0.18cm(2). Endoscopic foraminotomies resulted in a 15.3% increase of foraminal height (2.11±0.15cm, p<0.05) and 44.8% increase in area of (2.51±0.21cm(2), p<0.01). At L5-S1, spondylitic changes caused diminished foraminal height (1.26±0.14cm) and foraminal area (1.17±0.18cm(2)). Postoperatively, foraminal height increased by 41.6% (1.74±0.09cm, p<0.05) and area increased by 98.7% (2.08±0.17cm(2), p<0.01). Subsequent inspection via a standard midline approach revealed one dural tear of an S1 nerve root. Endoscopic foraminotomies allow for effective foraminal decompression, though clinical studies are necessary to further evaluate complications and efficacy.

Anterior cervical discectomy and fusion with a zero-profile integrated plate and spacer device: a clinical and radiological study: Clinical article.

OBJECT: Anterior cervical plating decreases the risk of pseudarthrosis following anterior cervical discectomy and fusion (ACDF). Dysphagia is a common complication of ACDF, with the anterior plate implicated as a potential contributor. A zero-profile, stand-alone polyetheretherketone (PEEK) interbody spacer has been postulated to minimize soft-tissue irritation and postoperative dysphagia, but studies are limited. The object of the present study was to determine the clinical and radiological outcomes for patients who underwent ACDF using a zero-profile integrated plate and spacer device, with a focus on the course of postoperative prevertebral soft-tissue thickness and the incidence of dysphagia. METHODS: Using a surgical database, the authors conducted a retrospective analysis of all patients who had undergone ACDF between August 2008 and October 2011. All patients received a Zero-P implant (DePuy Synthes Spine). The Neck Disability Index (NDI) and visual analog scale (VAS) scores for arm and neck pain were documented. Dysphagia was determined using the Bazaz criteria. Prevertebral soft-tissue thickness, spinal alignment, and subsidence were assessed as well. RESULTS: Twenty-two male and 19 female consecutive patients, with a mean age of 58.4 ± 14.68, underwent ACDF (66 total operated levels) in the defined study period. The mean clinical follow-up in 36 patients was 18.6 ± 9.93 months. Radiological outcome in 37 patients was assessed at a mean follow-up of 9.76 months (range 7.2-19.7 months). There were significant improvements in neck and arm VAS scores and the NDI following surgery. The neck VAS score improved from a median of 6 (range 0-10) to 0 (range 0-8; p < 0.001). The arm VAS score improved from a median of 2 (range 0-10) to 0 (range 0-7; p = 0.006). Immediate postoperative dysphagia was experienced by 58.4% of all patients. Complete resolution was demonstrated in 87.8% of affected patients at the latest follow-up. The overall median Bazaz score decreased from 1 (range 0-3) immediately postoperatively to 0 (range 0-2; p < 0.001) at the latest follow-up. Prevertebral soft-tissue thickness significantly decreased across all levels from a mean of 15.8 ± 4.38 mm to 10.1 ± 2.93 mm. Postoperative lordosis was maintained at the latest follow-up. Mean subsidence from the immediate postoperative to the latest follow-up was 4.1 ± 4.7 mm (p < 0.001). Radiographic fusion was achieved in 92.6% of implants. No correlation was found between prevertebral soft-tissue thickness and Bazaz dysphagia score. CONCLUSIONS: A zero-profile integrated plate and spacer device for ACDF surgery produces clinical and radiological outcomes that are comparable to those for nonintegrated plate and spacer constructs. Chronic dysphagia rates are comparable to or better than those for previously published case series.

Minimally invasive foraminotomy through tubular retractors via a contralateral approach in patients with unilateral radiculopathy.

BACKGROUND: Radiculopathy caused by foraminal nerve root compression is a common pathology in the lumbar spine. Surgical decompression via a conventional open foraminotomy is the treatment of choice when surgery is indicated. Minimally invasive tubular foraminotomy through a contralateral approach is a potentially effective surgical alternative. OBJECTIVE: The aim of this retrospective cohort study was to evaluate the efficacy and benefits of this approach for treatment of radiculopathy. METHODS: Patients with unilaterally dominant lower extremity radiculopathy, who underwent minimally invasive lumbar foraminotomy through tubular retractors via a contralateral approach between 2010 and 2012, were included. Oswestry Disability Index (ODI) and the Visual Analogue Scale (VAS) for back and leg pain were evaluated preoperatively, postoperatively, and at the latest follow-up. Functional outcome was evaluated by using the MacNab criteria. RESULTS: For the total 32 patients, postoperatively there was significant improvement in the ODI (P = .006), VAS back pain (P < .001), and VAS leg pain on the pathology and the approach side (P = .004, P = .021, respectively). At follow-up of 12.3 ± 1.7 months, there was also significant improvement in the ODI (P < .001), VAS back pain (P = .001), and VAS leg pain on the pathology and the approach side (P < .001, P = .001, respectively). The functional outcome was excellent and good in 95.2%. One patient required fusion (3.1%). CONCLUSION: A minimally invasive, facet-sparing contralateral approach is an effective technique for treatment of radiculopathy due to foraminal compression. It also allows for decompression of lumbar spinal stenosis and bilateral lateral recess decompression without the need for fusion.

Assessment of intervertebral disc degeneration based on quantitative magnetic resonance imaging analysis: an in vivo study.

STUDY DESIGN: Animal experimental study. OBJECTIVE: To evaluate a novel quantitative imaging technique for assessing disc degeneration. SUMMARY OF BACKGROUND DATA: T2-relaxation time (T2-RT) measurements have been used to assess disc degeneration quanti-tatively. T2 values correlate with the water content of intervertebral disc tissue and thereby allow for the indirect measurement of nucleus pulposus (NP) hydration. METHODS: We developed an algorithm to subtract out magnetic resonance imaging (MRI) voxels not representing NP tissue on the basis of T2-RT values. Filtered NP voxels were used to measure nuclear size by their amount and nuclear hydration by their mean T2-RT. This technique was applied to 24 rat-tail intervertebral discs (IVDs), which had been punctured with an 18-gauge needle according to different techniques to induce varying degrees of degeneration. NP voxel count and average T2-RT were used as parameters to assess the degeneration process at 1 and 3 months postpuncture. NP voxel counts were evaluated against radiograph disc height measurements and qualitative MRI studies on the basis of the Pfirrmann grading system. Tails were collected for histology to correlate NP voxel counts to histological disc degeneration grades and to NP cross-sectional area measurements. RESULTS: NP voxel count measurements showed strong correlations to qualitative MRI analyses (R = 0.79, P < 0.0001), histological degeneration grades (R = 0.902, P < 0.0001), and histological NP cross-sectional area measurements (R = 0.887, P < 0.0001).In contrast to NP voxel counts, the mean T2-RT for each punctured group remained constant between months 1 and 3. The mean T2-RTs for the punctured groups did not show a statistically significant difference from those of healthy IVDs (63.55 ms ± 5.88 ms mo 1 and 62.61 ms ± 5.02 ms) at either time point. CONCLUSION: The NP voxel count proved to be a valid parameter to assess disc degeneration quantitatively in a needle puncture model. The mean NP T2-RT does not change significantly in needle-puncture-induced degenerated IVDs. IVDs can be segmented into different tissue components according to their innate T2-RT.

Traumatic brain injury in a rural and an urban Tanzanian hospital--a comparative, retrospective analysis based on computed tomography.

BACKGROUND: In a resource-poor environment such as rural East Africa, expensive medical devices such as computed tomographic (CT) scanners are rare. The CT scanner at the rural Haydom Lutheran Hospital (HLH) in Tanzania therefore offers a unique chance to observe possible differences with urban medical centers in the disease pattern of trauma-related cranial pathologies. The purpose of this study was to compare traumatic brain injuries (TBIs) between a rural and an urban area of Tanzania. METHODS: HLH has 350 beds and one CT scanner. The urban Aga Khan Hospital is a private hospital with 80 beds and one CT scanner. This was a retrospective study. Data of 248 patients at HLH and of 432 patients at Aga Khan Hospital with TBI could be collected. RESULTS: The prevalence of TBI was significantly higher in the rural area compared to the urban area (34.2% vs. 21.9%, P < 0.0001). TBI due to violence was noted to occur more frequently at HLH, whereas road traffic accidents were more frequent at the Aga Khan Hospital. The number of patients showing a normal CT result was significantly higher in the urban area (53.0% vs. 35.9%, P < 0.0001). Bone fractures (35.9% vs. 15.7%, P < 0.0001) and pneumocephalus (6.9% vs. 0.9%, P < 0.0001) were diagnosed significantly more frequently in the rural survey. Soft tissue swelling (11.6% vs. 1.2%, P < 0.0001) and frontal sinus injuries (7.4% vs. 0.4%, P < 0.0001) were observed significantly more often in the urban setting. CONCLUSIONS: This study documents the burden of TBI and the differences in TBI-related CT diagnoses and their incidence between urban and rural areas in Eastern Africa. These results are important as they demonstrate that patients with severe TBI are not a primarily urban concern. Management of TBI should be included in the training curricula for health personnel alike irrespective of whether their workplace is primarily urban or rural.

Intrathecal pain pump infusions for intractable cancer pain: an algorithm for dosing without a neuraxial trial.

BACKGROUND: Patients with pain from advanced cancer often have limited life expectancy. Undergoing an epidural trial for placement of an intrathecal pump in these selected patients can exhaust limited days of life. We sought to analyze historical data at our cancer center to develop an algorithm to predict initial intrathecal pump dosing based on the starting preimplant systemic opioid regimen, thus averting an epidural trial and minimizing hospital stay. METHODS: We used data pre- and postpump from 46 cancer patients receiving systemic opioids undergoing intrathecal pump placement in the last 6 years, all of whom had undergone an epidural trial before pump placement. RESULTS: By analyzing intrathecal opioid dosage on discharge (in IV morphine equivalents) to age, type of pain, cancer type, preimplant opioid dose, and preimplant pain score using multiple regression, we created an algorithm that predicts, for cancer patients, an appropriate initial dose for an intrathecal pump based on the prepump systemic opioid dose, thus avoiding an epidural trial. The predicted value does have a broad 95% prediction interval (-122.7% to 147.6%) pointing to the value of a trial when feasible. CONCLUSIONS: When an epidural trial is not feasible and an intrathecal pump is required in a cancer patient, it is possible to predict an initial dose for the intrathecal pump based on the systemic opioid usage. This minimizes delays in achieving satisfactory analgesia and discharge to home.

Does the type of tibial component affect mechanical alignment in unicompartmental knee replacement?

PURPOSE: There are a number of factors responsible for the longevity of unicompartmental knee replacements (UKR). These include the magnitude of postoperative alignment and the type of material used. The effect of component design and material on postoperative alignment, however, has not been explored. MATERIALS AND METHODS: We retrospectively reviewed 89 patients who underwent UKR with robotic guidance. Patients were divided into two groups, according to whether they had received an all-polyethylene inlay component (Inlay group) or a metal-backed onlay component (Onlay group). We explored the magnitude of mechanical alignment correction obtained in both groups. RESULTS: Mean postoperative mechanical alignment was significantly closer to neutral in the Onlay group (mean=2.8°; 95% CI=2.4°, 3.2°) compared to the Inlay group (mean=3.9°; 95% CI=3.4°, 4.4°) (R2=0.65; P=0.003), adjusting for gender, BMI, age, side and preoperative mechanical alignment (Fig. 2). Further exploration revealed that the thickness of the tibial polyethyelene insert had a significant effect on postoperative alignment when added to the model (R2=0.68; P=0.01). CONCLUSION: Patients who received a metal-backed Onlay tibial component obtained better postoperative mechanical alignment compared to those who received all-polyethylene Inlay prostheses. The thicker overall construct of Onlay prostheses appears to be an important determinant of postoperative alignment. Considering their higher survivorship rates and improved postoperative mechanical alignment, Onlay prostheses should be the first option when performing medial UKR.