Cone Beam CT With Flat Panel Detector and Biplane Fluoroscopy-Guided Percutaneous Trigeminal Nerve Rhizotomy Using Three-Dimensional Needle Trajectory Planning.

Trigeminal-mediated pain disorders can be devastating for patients refractory to medical therapy. Gasserian ganglion blocks and percutaneous trigeminal rhizotomy have been used with success to treat these patients, however, serious complication risks include facial hematoma, cranial nerve palsy, and stroke. Cone beam CT, combined with fluoroscopy and needle navigation has been shown to decrease needle pass rates, procedure time, radiation exposure, and complications in multiple interventional radiology procedures, but hitherto has not been utilized for Gasserian ganglion interventions. Here, we present two cases of trigeminal-mediated pain successfully treated via cone beam CT combined fluoroscopy and needle navigation.

Evaluating the role of 1.5T quantitative susceptibility mapping for subthalamic nucleus targeting in deep brain stimulation surgery.

BACKGROUND AND PURPOSE: Quantitative susceptibility mapping (QSM) has been shown to be valuable in direct targeting for subthalamic nucleus (STN) DBS, given its higher quality of contrast between the STN border and adjacent anatomical structures. The objective is to demonstrate the feasibility of using 1.5T QSM for direct targeting in STN DBS planning. MATERIAL AND METHODS: Eleven patients underwent MRI acquisitions using a 1.5T scanner, including multi-echo gradient echo sequences for generating QSM images. 22 STN targets were planned with direct targeting method using QSM images by one stereotactic neurosurgeon and indirect targeting method using standard protocol by a second stereotactic neurosurgeon. The two physicians were blinded to each other's results. RESULTS: The mean coordinates for the STN using direct targeting relative to the mid-commissural point (MCP) was 11.41±2.43mm lateral, 2.48±0.53mm posterior and 4.45±0.95mm inferior. The mean coordinates for the STN using indirect targeting was 11.79±2.51mm lateral, 2.55±0.54mm posterior, and 4.84±1.03mm inferior. The mean (±SEM) radial error between the direct and indirect target was 0.67±0.14mm. In cases where DBS electrodes were implanted, the radial difference between the indirect and actual target (1.19±0.30mm) was statistically equivalent to the radial difference between the direct and actual target (1.0±0.27mm). CONCLUSIONS: Direct targeting of the STN for DBS implantation using 1.5T QSM was found to be statistically equivalent to standard protocol surgery planning. This may offer a simpler, more intuitive alternative for DBS surgery planning at centers with 1.5T MRIs.

Use of Functional Magnetic Resonance Imaging to Assess How Motor Phenotypes of Parkinson's Disease Respond to Deep Brain Stimulation.

BACKGROUND: Deep brain stimulation (DBS) is a well-accepted treatment of Parkinson's disease (PD). Motor phenotypes include tremor-dominant (TD), akinesia-rigidity (AR), and postural instability gait disorder (PIGD). The mechanism of action in how DBS modulates motor symptom relief remains unknown. OBJECTIVE: Blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI) was used to determine whether the functional activity varies in response to DBS depending on PD phenotypes. MATERIALS AND METHODS: Subjects underwent an fMRI scan with DBS cycling ON and OFF. The effects of DBS cycling on BOLD activation in each phenotype were documented through voxel-wise analysis. For each region of interest, ANOVAs were performed using T-values and covariate analyses were conducted. Further, a correlation analysis was performed comparing stimulation settings to T-values. Lastly, T-values of subjects with motor improvement were compared to those who worsened. RESULTS: As a group, BOLD activation with DBS-ON resulted in activation in the motor thalamus (p < 0.01) and globus pallidus externa (p < 0.01). AR patients had more activation in the supplementary motor area (SMA) compared to PIGD (p < 0.01) and TD cohorts (p < 0.01). Further, the AR cohort had more activation in primary motor cortex (MI) compared to the TD cohort (p = 0.02). Implanted nuclei (p = 0.01) and phenotype (p = <0.01) affected activity in MI and phenotype alone affected SMA activity (p = <0.01). A positive correlation was seen between thalamic activation and pulse-width (p = 0.03) and between caudate and total electrical energy delivered (p = 0.04). CONCLUSIONS: These data suggest that DBS modulates network activity differently based on patient motor phenotype. Improved understanding of these differences may further our knowledge about the mechanisms of DBS action on PD motor symptoms and to optimize treatment.

Robotic Assisted MRI-Guided Interventional Interstitial MR-Guided Focused Ultrasound Ablation in a Swine Model.

BACKGROUND: Ablative lesions are current treatments for epilepsy and brain tumors. Interstitial magnetic resonance (MR) guided focused ultrasound (iMRgFUS) may be an alternate ablation technique which limits thermal tissue charring as compared to laser therapy (LITT) and can produce larger ablation patterns nearer the surface than transcranial MR guided focused ultrasound (tcMRgFUS). OBJECTIVE: To describe our experience with interstitial focused ultrasound (iFUS) ablations in swine, using MR-guided robotically assisted (MRgRA) delivery. METHODS: In an initial 3 animals, we optimized the workflow of the robot in the MR suite and made modifications to the robotic arm to allow range of motion. Then, 6 farm pigs (4 acute, 2 survival) underwent 7 iMRgFUS ablations using MRgRA. We altered dosing to explore differences between thermal dosing in brain as compared to other tissues. Imaging was compared to gross examination. RESULTS: Our work culminated in adjustments to the MRgRA, iMRgFUS probes, and dosing, culminating in 2 survival surgeries; swine had ablations with no neurological sequelae at 2 wk postprocedure. Immediately following iMRgFUS therapy, diffusion-weighted imaging, and T1 weighted MR were accurate reflections of the ablation volume. T2 and fluid-attenuated inversion-recovery (FLAIR) images were accurate reflections of ablation volume 1-wk postprocedure. CONCLUSION: We successfully performed MRgRA iFUS ablation in swine and found intraoperative and postoperative imaging to correlate with histological examination. These data are useful to validate our system and to guide imaging follow-up for thermal ablation lesions in brain tissue from our therapy, tcMRgFUS, and LITT.

Intraoperative Neuromonitoring in Percutaneous Spinal Cord Stimulator Placement.

INTRODUCTION: Placement of spinal cord stimulation (SCS) paddles under general anesthesia using intraoperative neuromonitoring (IONM) has been shown to be associated with equivocal or superior clinical outcomes in comparative studies. The value of IONM in percutaneous permanent SCS placement has not been demonstrated. METHODS: Outcomes for patients under percutaneous SCS placement performed with IONM were prospectively collected. Descriptive outcomes included numerical rating scale (NRS), the Oswestry disability index (ODI), McGill pain questionnaire, pain catastrophizing scale score (PCS), and Beck Depression Inventory. We also assessed satisfaction, willingness to repeat surgery, complication rates, and opioid use at baseline and follow-up using chart data and the New York Internet System for Tracking Over-Prescribing data base. RESULTS: The mean follow-up for our 46 patients was 22.04 ± 15.03 months (range 6-52 months). There were 10 patients (21.3%) who underwent revisions or removals with a mean time to revision/explant of 11.4 ± 11.7 months. About 85% of patients were satisfied with surgery. A total of 24 of 46 patients were on opioids at baseline. Following surgery, 17 of 24 (70.83%) patients demonstrated decreased opioid use in Morphine Milligram Equivalents. Of the 17 patients that reduced opioid use, 14 (82.35%) ceased opioid use entirely. Improvement from baseline was noted in NRS, ODI, and PCS (p < .05). CONCLUSIONS: Permanent percutaneous implantation of a SCS system using IONM with general anesthesia demonstrates results within range to those in the literature. Patients demonstrated statistically significant improvement in outcomes and opioid use was reduced in 71% of patients who were using opioids at baseline. We recommend its use in patients with morbid obesity, sleep apnea, and considerable anxiety. Further research is warranted to define the possible future role for percutaneous SCS implantation under IONM.

A Novel Approach to Avoid Baclofen Withdrawal When Faced With Infected Baclofen Pumps.

BACKGROUND: Intrathecal (IT) Baclofen is beneficial for spasticity, but if pumps become infected necessitating removal, baclofen withdrawal is difficult to manage and life-threatening. Furthermore there is no consistency between dosing and severity of withdrawal. Case reports detail full baclofen withdrawal at dosages of 260 µg/day. OBJECTIVE: To demonstrate that in patients on stable IT baclofen for prolonged periods, externalizing a patient's original IT pump is a safe, effective way to wean IT doses. METHODS: Here, we describe a technique of continuing IT baclofen when urgent pump removal is needed. Specifically, we remove the infected pump. Then using a new or existing lumbar drain based on extent of infection, we reconnect the pump after cleaning with betadine and administer therapy externally during IT weaning. RESULTS: Hundred forty seven baclofen pumps were implanted or replaced within four years. Infections occurred in seven patients. We utilized this technique in five of seven patients. Mean IT dose at time of explant was 400.5 ± 285.3 µg/day. We titrated the dose by 20-50% per day based on clinical response over a mean of 6.2 ± 1.3 days. The catheter was removed at bedside once weaning was complete. No patients had any signs of withdrawal, excluding minimal spasticity increases while optimizing oral treatment. CONCLUSION: Here, we show preliminary evidence that an externalized IT pump is an effective means of weaning IT baclofen when infection of the pump occurs. This treatment strategy warrants further investigation, but appears to be a safe and effective. CONFLICT OF INTEREST: Dr. Pilitsis is a consultant for Medtronic, Boston Scientific, Nevro, Jazz Pharmaceuticals, Neurobridge Therapeutics, and Abbott and receives grant support from Medtronic, Boston Scientific, Abbott, Nevro, Jazz Pharmaceuticals, GE Global Research and NIH 1R01CA166379. She is medical advisor for Centauri and Karuna and has stock equity. Dr. Sukul receives consultant fees from Medtronic. Julia Prusik receives grant support from Jazz Pharmaceuticals.

Efficacy of Alternating Conventional Stimulation and High Frequency Stimulation in Improving Spinal Cord Stimulation Outcomes: A Pilot Study.

INTRODUCTION: Spinal cord stimulation (SCS) is an established, effective method of treating chronic pain. High frequency stimulation (HFS) is an alternative SCS waveform that has been shown to alleviate pain but also necessitates more frequent recharging. The purpose of this pilot study is to evaluate efficacy of alternating conventional stimulation and HFS (termed "shuffle" stimulation) in improving SCS outcomes. METHODS: Shuffle stimulation was designed to deliver conventional stimulation in upright positions with relative HFS in lying positions, automated through accelerometer technology. In this 13-week cross-over study, patients were randomized to receiving conventional and shuffle stimulation in four-week blocks. Pain outcomes and sensory testing were compared from preoperative baseline and at the conclusion of each study period. RESULTS: Twelve patients completed this study. Two patients showed no change from baseline visual analogue scale (VAS) with either type of stimulation and were excluded from statistical analysis of pain outcomes. Mean numerical rating scale (NRS) scores assessing current pain were significantly lower in shuffle stimulation (4.0 ± 1.6) compared to conventional stimulation (5.8 ± 2.3) (p = 0.024). In the total cohort, 7 of 11 patients preferred shuffle over conventional stimulation. CONCLUSIONS: This study generated preliminary evidence showing improved NRS current pain scores in shuffle stimulation compared to conventional stimulation. More patients preferred shuffle stimulation compared to conventional stimulation. Optimizing stimulation when patients are recumbent may increase patient satisfaction and pain control. The potential advantages of shuffle stimulation may warrant further investigation.

Magnetic resonance-guided interstitial high-intensity focused ultrasound for brain tumor ablation.

Currently, treatment of brain tumors is limited to resection, chemotherapy, and radiotherapy. Thermal ablation has been recently explored. High-intensity focused ultrasound (HIFU) is being explored as an alternative. Specifically, the authors propose delivering HIFU internally to the tumor with an MRI-guided robotic assistant (MRgRA). The advantage of the authors' interstitial device over external MRI-guided HIFU (MRgHIFU) is that it allows for conformal, precise ablation and concurrent tissue sampling. The authors describe their workflow for MRgRA HIFU delivery.

Relationship of the sinus anatomy to surface landmarks is a function of the sinus size difference between the right and left side: Anatomical study based on CT angiography.

BACKGROUND: Several cadaveric studies demonstrate reliable localization of the transverse sinus and the transverse sigmoid junction (TSJ). These studies use the line drawn from the inion to the posterior root of the zygoma (IZ) and the asterion, respectively. We investigated how the size difference between the right and left transverse sinuses (TS) and sigmoid sinuses (SS) affected the accuracy of their respective superficial landmarks, particularly with regards to where this relationship may result in unsafe and/or complicated surgical access. METHODS: We utilized Vitrea software to render three-dimensional images based on computed tomographic angiography (CTA). We measured the relationship between the TS and SS to their respective superficial landmarks. RESULTS: We analyzed 50 patients in this study. The distal TS was found caudal to the inion-to-zygoma (IZ) line on average by 5.0 ± 4.3 mm on the right and 6.4 ± 9.3 mm on the left. The mid TS was found cranial on average 3.5 ± 5.7 mm on the right and 3.2 ± 6.0 mm cranial on the left to the superior nuchal line (SNL). The distance from the asterion to the SS was 11.5 ± 2.4 mm medial on the right and 12.1 ± 4.4 mm medial on the left. The average distance was greater on the left than the right when using the IZ landmark. This was directly proportional to the size difference of the sinuses (r2 = 0.15, P = 0.03). CONCLUSIONS: Statistically significant differences between the right and left TS and SS were seen in terms of size. This appeared to correlate nicely to the differences observed between the locations of the TSs' and their respective superficial landmarks.

Lung cancer metastasis presenting as a solitary skull mass.

Lung cancer has been well documented to spread to bone and the axial skeleton after metastasis to adjacent organs. Bony metastasis is not, however, the typical presenting manifestation. The differential diagnosis for a tissue mass on the skull should warrant a workup for metastatic disease. Bony metastasis plays an important role in treatment and disease management. We report an exceptionally rare case of stage IV lung adenocarcinoma that presented with a solitary skull metastasis and a significant soft-tissue component. The lesion was treated by excision via craniotomy and subsequent medical management of the adenocarcinoma. This case illustrates a very rare presentation of lung adenocarcinoma and also represents what the authors believe to be the first report of a solitary skull mass originating from a lung primary. We also present a review of the literature surrounding bony metastasis to the skull and implications for patient care.

Treatment of holocord spinal epidural abscess via alternating side unilateral approach for bilateral laminectomy.

To date, this is the first reported case of the surgical management of a holocord epidural abscess done through level-skipping laminectomies. It is also the first reported case of these laminectomies being performed via an alternating side unilateral approach for this condition. A 51-year-old patient presenting with progressive lower extremity weakness secondary to a spinal epidural abscess extending from C4 to S1. A minimally disruptive method of relieving the spinal cord compression via evacuation of the abscess was employed successfully. This report demonstrates the efficacy of level skipping laminectomies via a unilateral approach for holocord epidural abscesses (extending 20 vertebral levels). Performing the laminectomies via a unilateral approach as well as alternating the side of the approach minimized iatrogenic instability risk. Both strategies were designed to minimize incision size, tissue disruption, and the amount of muscular weakness/imbalance postoperatively.

Complications and Outcomes for Surgical Approaches to Cervical Kyphosis.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: The primary objective of this study is to report the safety and efficacy of the different surgical approaches to cervical deformity correction surgery. SUMMARY OF BACKGROUND DATA: Cervical subaxial deformity surgery has been shown to be an effective means to alleviate pain and improve neurological function in symptomatic patients. The reported outcomes and complications for the different surgical approaches (ventral, dorsal, and combined) are limited to small retrospective studies. The appropriate surgical approach is at times unclear, which is likely attributed to the overlap in indications for the ventral and combined approach. MATERIALS AND METHODS: A retrospective review of 76 patients who underwent cervical deformity surgery for cervical kyphosis at 1 institution was performed. The authors reviewed the complications, radiographic outcomes, and long-term functional outcomes for all patients. RESULTS: The majority of patients in all groups reported excellent (15%) or good (50%) outcomes, with a mean improvement in modified Japanese orthopedic association score of 1.3. There were 26 perioperative complications (34%) for 19 patients (25%). We found the ventral-alone and combined approaches to achieve similar degrees of correction (23.1 and 23.2 degrees, respectively). The combined approach had the highest complication rate of the 3 approaches (combined: 40%, ventral: 30%, dorsal: 27%). The dorsal, ventral, and combined approaches had a mean neurological improvement in modified Japanese orthopedic association scores of 1.95, 3.00, and 1.26, respectively, and mean pain improvement of 0.8, 2.0, and 1.4. CONCLUSIONS: Given the moderate improvements in long-term outcomes, and the risks for perioperative complications, we recommend a careful selection process for patients eligible for cervical deformity surgery. We found that the ventral approach has reduced complications, similar degree of correction capability, and potentially higher improved neurological outcomes compared to the combined approach.

Relationship between degree of focal kyphosis correction and neurological outcomes for patients undergoing cervical deformity correction surgery.

OBJECT: Reversal of the normal cervical spine curvature, as seen in cervical kyphosis, can lead to mechanical pain, neurological dysfunction, and functional disabilities. Surgical intervention is warranted in patients with sufficiently symptomatic deformities in an attempt to correct the deformed cervical spine. In theory, improved outcomes should accompany a greater degree of correction toward lordosis, although there are few data available to test this relationship. The purpose of this study is to determine if the degree of deformity correction correlates with improvement in neurological symptoms following surgery for cervical kyphotic deformity. METHODS: A retrospective review of 36 patients with myelopathic symptoms who underwent cervical deformity correction surgery between 2001 and 2009 was performed. Preoperative and postoperative radiographic findings related to the degree of kyphosis were collected and compared with functional outcome measures. The minimum follow-up time was 2 years. RESULTS: A significant relationship was observed between a greater degree of focal kyphosis correction and improved neurological outcomes according to the modified Japanese Orthopaedic Association (mJOA) score (r = -0.46, p = 0.032). For patients with severe neurological symptoms (mJOA score < 12) a trend toward improved outcomes with greater global kyphosis correction was observed (r = -0.56, p = 0.057). Patients with an mJOA score less than 16 who attained lordosis postoperatively had a significantly greater improvement in total mJOA score than patients who maintained a kyphotic position (achieved lordosis: 2.7 ± 2.0 vs maintained kyphosis: 1.1 ± 2.1, p = 0.044). CONCLUSIONS: The authors' results suggest that the degree of correction of focal kyphosis deformity correlates with improved neurological outcomes. The authors also saw a positive relationship between attainment of global lordosis and improved mJOA scores. With consideration for the risks involved in correction surgery, this information can be used to help guide surgical strategy decision making.

Circumferential cervical surgery: to stage or not to stage?

STUDY DESIGN: Retrospective review. OBJECTIVE: The objective of the study was to determine the morbidity and mortality rate associated with same day versus staged cervical circumferential approach. SUMMARY OF BACKGROUND DATA: A combined approach to the cervical spine is often indicated for complex cervical pathologies. Previous studies suggested superior results associated with same day combined surgery for thoracolumbar patients. This study examines the usefulness of p-Physiological and Operative Severity Score for enumeration of Morbidity and Mortality (POSSUM), an estimated mortality risk assessment for cervical spine patients and will compare same day surgery to staged procedures. METHODS: This is a retrospective chart review including patients who underwent ventral and dorsal approach within 2 weeks. Estimated mortality was calculated using p-POSSUM. The cohort was divided into same day surgery group and staged group. Risk factors were compared between groups. Mean p-POSSUM was calculated and compared with the actual mortality rate. Univariate analysis was used to compare the risk factors between groups and the groups' outcomes. Multivariable analysis was used to adjust for risk factor differences when comparing group outcomes. RESULTS: One hundred thirty-five patients were included, 106 patients were in the same day surgery group whereas 29 patients were in the staged group. Mean p-POSSUM was 2.8% predicted mortality with a 95% confidence interval of 1.6% to 4.1%. The actual mortality rate was 3.7%. The groups did not vary in most risk factors assessed. Univariate analysis demonstrated a statistically significantly higher rate of major complications (0.62 vs. 0.34, P=0.0369), infection (41.4% vs. 9.4%, P<0.0001), and length of hospital stay (9.3 vs. 6.8 d, P=0.0120) in the staged group. Multivariable analysis demonstrated significantly higher infection rate in the staged group. CONCLUSIONS: P-POSSUM mortality estimate may serve as a useful and valid tool for spine surgery studies. Staged combined cervical surgery harbors a higher complication rate and may be associated with lengthier hospitalization.

Surgery for primary hyperparathyroidism: are the consensus guidelines being followed?

OBJECTIVE: To determine parathyroidectomy (PTx) rates in patients who satisfy the consensus guidelines for surgical treatment of primary hyperparathyroidism (PHPT). BACKGROUND: Surgery for PHPT is recommended for all symptomatic patients and select asymptomatic patients meeting established consensus criteria. Adherence to the consensus guidelines has not been examined systematically, because of inadequate information regarding patients managed nonoperatively. METHODS: All nonuremic patients with PHPT during the period 1995-2008 were identified using the Kaiser Permanente-Southern California laboratory database, encompassing 3.5 million individuals annually. Multivariate logistic regression was used to examine predictors of PTx. RESULTS: We found 3388 patients with PHPT, of whom 265 (8%) were symptomatic (nephrolithiasis). Nephrolithiasis was predictive of PTx (OR 2.94 vs asymptomatic), with 51% of symptomatic patients undergoing surgery. Among asymptomatic patients, the proportion meeting consensus criteria was 39% during the early period (1995-2002) and 51% during the late period (2003-2008). The PTx rate for these patients exceeded that for asymptomatic patients not meeting consensus criteria but remained low (early 44% vs 19%, P < 0.0001; late 39% vs 16%, P < 0.0001). The following individual criteria were predictive of PTx: calcium >11.5 mg/dL (OR 2.27), hypercalciuria (OR 3.28, P < 0.0001), and age < 50 years (OR 1.54, P < 0.0001). However, the absolute PTx rates associated with satisfaction of these criteria were in the 50% range. Bone density scores did not influence likelihood of PTx and renal impairment predicted against PTx (OR 0.35, P < 0.0001). CONCLUSIONS: The consensus guidelines regarding PHPT have not been followed in our study population. PTx appears to be underutilized in both asymptomatic and symptomatic patients.

Comparing vertebral body reconstruction implants for the treatment of thoracic and lumbar metastatic spinal tumors: a consecutive case series of 37 patients.

STUDY DESIGN: Retrospective case series. OBJECTIVE: To compare different interbody reconstruction implants after corpectomy in metastatic spine tumors. SUMMARY OF BACKGROUND DATA: Vertebral body reconstruction after corpectomy is common for patients with metastatic spine tumors. Although various implants are reported individually in the literature, no study to-date has compared them with one another directly. METHODS: Thirty-seven consecutive patients with metastatic tumors of the thoracic or lumbar spine underwent single or multilevel corpectomy with subsequent interbody reconstruction. Longevity of interbody graft was primarily evaluated in this study as defined by the need for any revision surgeries or complications after surgery. Data was collected retrospectively. RESULTS: Twenty-seven, 5, and 5 patients underwent reconstruction with metal implants, bone implants, and polymethylmethacrylate (PMMA), respectively. Twenty-three patients had metastatic tumor involvement of the thoracic spine and 14 patients had tumor involvement of the lumbar spine. Three patients (8.1%) required additional surgery: 1 wound infection, 1 hardware revision, and 1 for resection of an intradural, intramedullary tumor not identified at the first operation. Overall complication rate was 43.2% (16 patients) and 2 patients died within 30 days of their index spine surgery. Postoperative complication rates were more than double in the metal implant group (52%) compared with an equal number of complications in bone (20%) and PMMA (20%) implant group. The rate of revision surgery was highest in the bone group (40%) compared with none in the PMMA and only 3.7% in the metal interbody groups. CONCLUSIONS: Vertebral body reconstruction after corpectomy for patients with metastatic tumors to the thoracic and lumbar spine can be performed effectively with metal, bone, or cement implants. Although metal implants are used in the majority of reconstruction cases, they seem to have a higher rate of overall complications, with bone interbody constructs showing a higher rate of revision surgery.

Strategic impact of a new academic endocrine surgery program.

BACKGROUND: A minority of medical centers possess a dedicated endocrine surgery program. Here we assess the short-term impact of a new endocrine surgery program on institutional case volumes and financial endpoints. METHODS: We studied all endocrine procedures performed over a 5-year period spanning the inception of the endocrine surgery program at UCLA. Institutional and state-level data on patient geographic origin, discharges for endocrine diagnosis-related groups (DRGs), and hospital-side charges and costs were examined. RESULTS: Total endocrine case volume increased 112% (264 to 559 cases annually) over the study period. The relative increase was greater for parathyroid (56 to 196, 250%, P < 0.0001) and adrenal (11 to 31, 181%, P = 0.06) procedures compared to thyroid procedures (317 to 442, 39%). The endocrine case volume of nonspecialist surgeons remained stable over the study period. Growth in referrals arose from previously unrepresented zip codes and was associated with an increase in the mean distance traveled for care (2006, 44 miles vs. 2009, 92 miles, P < 0.01). In each DRG, UCLA attained the top market position within one year of the program's inception, corresponding to an overall 27% increase in regional market share. Total hospital charges for endocrine DRGs rose 161% to $14.7 million annually, while the cost of parathyroid surgery fell 34% (P < 0.001). CONCLUSIONS: The establishment of an academic endocrine surgery program can cause fundamental shifts in referral patterns within a competitive, densely populated metropolitan environment. Hospitals should consider the inclusion of an endocrine surgery program in strategic planning initiatives.

Underutilization of parathyroidectomy in elderly patients with primary hyperparathyroidism.

CONTEXT: Primary hyperparathyroidism (PHPT) disproportionately affects older patients, who may face higher thresholds for surgical intervention compared to young patients. OBJECTIVE: The aim was to examine for differences in the utilization of parathyroidectomy attributable to age. DESIGN: We conducted a retrospective cohort study. PARTICIPANTS: Patients with biochemically diagnosed PHPT during the years 1995-2008 were identified within an integrated health care delivery system in Southern California encompassing approximately 3 million individuals. MAIN OUTCOME MEASURES: The outcome measures were parathyroidectomy (PTx) and time interval to surgery. RESULTS: We found 3388 patients with PHPT, 964 (28%) of whom underwent PTx. Patients aged 60+ yr comprised 60% of the study cohort. The likelihood of PTx decreased linearly among patients aged 60+ when compared to patients aged 50-59, an effect that persisted in multivariate analysis: odds ratio 0.68 for ages 60-69 (P < 0.05); 0.41 for ages 70-79 (P < 0.0001), and 0.11 for age 80+ (P < 0.0001). The PTx rate for patients aged 70+ was 14%. Among patients meeting 2002 consensus criteria for surgical treatment, 45% of those aged 60-69 and 24% of those aged 70+ underwent PTx. A Cox proportional hazards model showed that patients aged 60+ experienced significantly longer delays from diagnosis to surgery compared to young patients (P < 0.0001). CONCLUSIONS: PHPT is undertreated in the elderly. We observed a progressive age-related decline in PTx rate that renders patients aged 70+ unlikely to have definitive treatment, irrespective of comorbidity and eligibility for surgery.

A selective, Bayesian approach to intraoperative PTH monitoring.

OBJECTIVE: To determine if the performance of intraoperative parathyroid hormone monitoring (IPM) can be optimized by limiting its application to patients with weak preoperative localization. BACKGROUND: The value of IPM during minimally invasive parathyroidectomy (MIP) has been questioned, particularly in cases with strong preoperative localization. We describe a novel, Bayesian strategy employing IPM in select patients with a high pretest probability of multiple gland disease (MGD). METHODS: We prospectively examined 361 consecutive patients undergoing surgery for primary hyperparathyroidism. All patients underwent sestamibi (MIBI) scanning and surgeon-performed ultrasound. Intraoperative PTH levels were only used for surgical decision-making in the MIBI-negative, ultrasound-positive patient subset. The following outcomes were analyzed: MGD rate, test performance, success rate, and operative time. RESULTS: Patients with any positive localization study (91%) were offered MIP. The success rate was 99%. The MGD rate was 3% in MIBI-positive patients and 36% in MIBI-negative patients (10% overall, P < 0.0001). MIBI and surgeon-performed ultrasound were equally sensitive (80% vs. 85%, NS). Among MIBI-negative patients, 71% of whom underwent MIP with IPM, an inadequate fall in the 10-minute postexcision PTH level was highly predictive of MGD, saving 10 failures while causing 1 inappropriate conversion to bilateral exploration (negative likelihood ratio, NLR 28.0). In contrast, among MIBI-positive patients, IPM could have saved 3 failures at the expense of 18 inappropriate conversions (NLR 9.9). IPM increased operative time from 34 to 60 minutes (P < 0.0001). CONCLUSION: IPM is more likely to guide the surgeon correctly when used only in MIBI-negative patients, who have a high pretest probability of MGD. This selective strategy maintains high success rates while limiting the frequently adverse impact that IPM carries when used indiscriminately.