Minimally Effective Dose of Bone Morphogenetic Protein in Minimally Invasive Lumbar Interbody Fusions: Six Hundred Ninety Patients in a Dose-Finding Longitudinal Cohort Study.

STUDY DESIGN: Retrospective longitudinal cohort. OBJECTIVE: We sought to demonstrate the minimally effective bone morphogenetic protein (BMP) dose to achieve fusion in minimally invasive transforaminal lumbar interbody fusions. SUMMARY OF BACKGROUND DATA: Multiple studies have been conducted, which used a wide range of BMP doses for lumbar fusions highlighting associated risks and benefits. There is, however, a paucity in the literature in determining the minimally effective dose. METHODS: Consecutive patients who underwent transforaminal lumbar interbody fusion from 2009 to 2014 were reviewed. Fusion was determined by a combination of computed tomography and dynamic x-ray by independent radiologists. We used backward stepwise multiple logistic regression with fusion as the dependent variable to determine whether BMP dose/level was a significant predictor for fusion. To determine the minimally effective dose of BMP/level, separate logistic regressions for different BMP dose ranges and sensitivity analyses were used. A P value ≤0.025 was considered significant. RESULTS: There were 1102 interspaces among 690 patients. Average BMP dose was 1.28 mg/level. Overall fusion was 95.2% with a mean follow-up of 19 months. BMP dose/level was a significant predictor for fusion. Odds of fusion increased by 2.02 when BMP dose range was increased from (0.16-1 mg/level) to (1.0-2 mg/level), but fusion odds did not increase when BMP dose increased to more than 2 mg/level. CONCLUSION: BMP dose/level was a significant predictor for fusion. There was a significant increase in odds of fusion when BMP dose increased from 0.16 to 1 mg/level to 1.0 to 2 mg/level. No benefit from increasing the dose more than 2 mg/level was found, suggesting 1.0 mg/level to be the minimally effective BMP dose. LEVEL OF EVIDENCE: 3.

Project to Improve the Transcription of Clinical Order Information into a Radiology Information System.

CONTEXT: Inaccurate and incomplete imaging order information presented to interpreting radiologists is a persistent problem in many radiology settings. Computerized Physician Order Entry processes in clinic-based settings are often inconsistent, and radiology transcription clerks continue to play a critical role in transmitting accurate content and information from referring physician orders to the radiology information system. (RIS) The purpose of this quality improvement project was to a) identify common transcription areas of deficient RIS imaging order information and b) test outcomes from an intervention to improve the content and concordance of transcribed patient information entered into the RIS. METHODS: A random convenience sample of 500 outpatient radiographic orders were categorized according to degree and quality of concordance between the transcribed patient information documented in the RIS and the corresponding original imaging order information. During Phase I, the authors used a root-cause analysis to determine the possible etiologies for discordance between the information in original imaging orders and the information transcribed into the RIS. The intervention that was delivered included a short education session with radiology transcription clerks with placement reminder posters at transcription workstations. During Phase 2, a second random sample was obtained following the intervention, with data collection and analyses replicating the process from Phase I. A set of inferential comparisons were conducted using chi-square tests to examine for statistical significance. RESULTS: There was an overall 44% decrease in transcription discordance (p < 0.001), and the number of cases with perfectly concordant RIS order indication documentations increased by 21% (p < 0.001). A total of 34% of transcriptions from Phase I were partially discordant due to an inadequate imaging study indication, compared to 15% during Phase II (p < 0.001). There was also a 22% increase in the number of completely concordant transcriptions free of grammatical errors (p < 0.001). CONCLUSIONS: A short education session with radiology transcription clerks along with placement of reminder posters may significantly improve both the concordance and quality of transcribed imaging order information presented to interpreting radiologists using the RIS.

Cochlear Patency After Transmastoid Labyrinthectomy for Ménière's Syndrome.

OBJECTIVE: Labyrinthectomy is considered the "gold standard" in the treatment of intractable vertigo attacks because of Ménière's Disease (MD) but sacrifices all residual hearing. Interest in auditory rehabilitation has lead to cochlear implantation in some patients. Concern remains that the cochlear lumen may fill with tissue or bone after surgery. This study sought to determine the incidence of obliteration of the cochlea after transmastoid labyrinthectomy. STUDY DESIGN: Retrospective observational study. SETTING: Tertiary referral center. PATIENTS: Eighteen patients with intractable vertigo from MD who underwent surgery. INTERVENTIONS: Transmastoid labyrinthectomy between 2008 and 2013. Cochleas were imaged with unenhanced, heavily T2-weighted magnetic resonance imaging (MRI). MAIN OUTCOME MEASURE: Presence of symmetrical cochlear fluid signals on MRI. RESULTS: There was no loss of fluid signal in the cochleas of operated ear compared with the contralateral, unoperated ear in any subject an average of 3 years (standard deviation [SD]: 1.2) after surgery. Five of 18 patients had the vestibule blocked with bone wax at the time of surgery. Blocking the vestibule with bone wax did not change the cochlear fluid signal. CONCLUSION: The risk of cochlear obstruction after labyrinthectomy for MD is very low. The significance of this finding is that patients with MD who undergo labyrinthectomy will likely remain candidates for cochlear implantation in the labyrinthectomized ear long after surgery if this becomes needed. Immediate cochlear implantation or placement of a cochlear lumen keeper during labyrinthectomy for MD is probably not necessary.

Preventing proximal junctional failure in long segmental instrumented cases of adult degenerative scoliosis using a multilevel stabilization screw technique.

BACKGROUND: The authors sought to demonstrate the safety and effectiveness of the multilevel stabilization screw (MLSS) technique in decreasing the incidence of proximal junctional failure in long segmental instrumented fusions for adult degenerative scoliosis. METHODS: Institutional review board approval was obtained and all patients with adult spinal deformity who underwent the MLSS technique were analyzed. A neuro-radiologist and spine-focused neurosurgeon not involved with the surgical treatment performed radiographic analysis. Proximal junctional angle was defined as the caudal endplate of the upper instrumented vertebra (UIV) to the cephalad endplate of two supradjacent vertebrae above the UIV. The UIV is defined as the most cephalad vertebra completed captured by the instrumentation. Abnormal proximal junctional kyphosis (PJK) was defined as proximal junctional sagittal Cobb angle >10 degrees and proximal junction sagittal Cobb angle at least 10 degrees greater than the preoperative measurement. The presence of both is criteria necessary to be considered abnormal. RESULTS: Twenty patients with degenerative scoliosis underwent the MLSS technique with the upper-instrumented vertebrae in the proximal thoracic spine. Fifteen patients met inclusion criteria with greater than 12 months radiographic and clinical follow up. Three patients were excluded due to lack of follow up imaging and two patients were excluded due to the inability to measure the UIV. Age range was 44-84 years with a mean of 66. Eleven of the 15 patients were over the age of 60 at the time of surgery. The male-to-female ratio was 4:11. Body mass index (BMI) range was 24-44 with a mean of 31.5 units. The follow up period ranged from 14 to 58 months with an average follow up of 30 months. The mean change in Cobb angle at the proximal junction was 4.00 degrees with a range from -0.92 to 9.13 degrees. There were no fractures or instrumentation failures at or near the proximal junction. There was no revision surgeries performed for proximal junctional failure. Retrospective clinical questionnaires revealed that surgical expectations were met in 15 of 19 patients surveyed, 79%. One patient was not reachable for a postoperative phone interview. In patients who were not satisfied with their overall experience, the change in Cobb angle ranged from -0.92 to 9.13 degrees with an average change of 3.90 degrees. Whereas patients reporting an overall positive experience had a change in Cobb angle range from -0.12 to 8.07 degrees with an average change of 4.05 degrees. CONCLUSION: PJK and failure are well-recognized suboptimal outcomes of long-segmental fusions of the thoracolumbar spine that can lead to significant neurological morbidity and costly revision surgeries. With no known proximal junction failures to date, the MLSS technique has shown promising results in preventing adverse proximal junctional conditions and can be safely performed under fluoroscopy guidance. Future direction includes a comparative study establishing the relative risk of developing PJK with this novel technique versus a traditional long-segmental thoracolumbar fusion.

A novel approach to treatment of unexpected vertebroplasty complication.

We report a novel approach to treatment of an unexpected complication of vertebroplasty. During initial positioning of transpedicular vertebroplasty needles in a 73-year-old woman, we encountered unexpected ease of needle advancement resulting in progression of the needle through the anterior cortex of the thoracic vertebral body. The transpedicular needle advanced into the mediastinum and, presumably, the adventitia of the descending thoracic aorta. Administration of polymethylmethacrylate cement was performed to tamponade bleeding at the time of the procedure and to reduce the risk of potential delayed bleeding complications within the mediastinum. The treatment was successful and the patient had no immediate or delayed complications as a result of the unintended needle advancement.

Vessel-sparing prostate radiotherapy: dose limitation to critical erectile vascular structures (internal pudendal artery and corpus cavernosum) defined by MRI.

PURPOSE: Most evidence suggests that impotence after prostate radiation therapy has a vascular etiology. The corpus cavernosum (CC) and the internal pudendal artery (IPA) are the critical vascular structures related to erectile function. This study suggests that it is feasible to markedly decrease radiation dose to the CC and the IPA and directly determine the impact of dose limitation on potency. METHODS AND MATERIALS: Twenty-five patients (10 external beam, 15 brachytherapy) underwent MRI/CT-based treatment planning for prostate cancer. In addition, 10 patients entered on the vessel-sparing protocol underwent a time-of-flight MRI angiography sequence to define the IPA. The distance from the MRI-defined prostate apex to the penile bulb (PB), CC, and IPA was measured and compared to the distance from the CT-defined apex. Doses (D5 and D50) to the PB, CC, and IPA were determined for an 80 Gy external beam course. In 5 patients, CT plans were generated and compared to MRI-based plans. RESULTS: The combination of coronal, sagittal, and axial MRI data sets allowed superior definition of the prostate apex and its relationship to critical vascular structures. The apex to PB distance averaged 1.45 cm (0.36 standard deviation) with a range of 0.7 cm to 2.1 cm. Peak dose (D5) to the proximal CC in the MRI-planned 80 Gy course was 26 (9) Gy (0.36 of CT-planned dose), and peak dose to the IPA was 39 (13) Gy (0.61 of CT-planned dose). CONCLUSION: The distance between the prostate apex and critical vascular structures is highly variable. Current empiric rules for CT contouring (apex 1.5 cm above PB) overestimate or underestimate the distance between the prostate apex and critical vascular structures. When defined by MRI T2 and MRI angiogram with CT registration, limitation of dose to critical erectile structures is possible, with a more significant gain than has been previously reported using dose limitation by commonly applied intensity modulated radiation therapy studies based on CT imaging. These techniques make "vessel-sparing" prostate radiotherapy feasible.