Risk Factors of Screw Malposition in Robot-Assisted Cortical Bone Trajectory: Analysis of 1344 Consecutive Screws in 256 Patients

STUDY DESIGN

Retrospective single-center study using prospectively collected data.

OBJECTIVE

To describe the incidence of and identify risk factors for intraoperative screw malposition secondary to skive or shift during robot-assisted cortical bone trajectory (RA-CBT) insertion.

SUMMARY OF BACKGROUND DATA

RA-CBT screw malposition occurs through 2 distinct modes, skive or shift. Skive occurs when a downward force applied to the cannula, drill, tap, or screw, causes the instrument to deflect relative to its bony landmark. Shift is a change in the position of the RA system relative to the patient after registration.

PATIENTS AND METHODS

A consecutive series of patients older than 18 years who underwent RA-CBT screw placement between January 2019 and July 2022 were enrolled. Baseline demographic and surgical data, Hounsfield Units (HUs) at L1, and vertebral shape related to screw planning were collected. Skive or shift was recorded in the operating room on a data collection form.

RESULTS

Of 1344 CBT screws in 256 patients, malposition was recognized intraoperatively in 33 screws (2.4%) in 27 patients (10.5%); 19 through skive in 17 and 14 through shift in 10 patients. These patients had higher body mass index than patients without malposition (33.0 vs. 30.5 kg/m 2 , P = 0.037). Patients with skive had higher HU (178.2 vs . 145.2, P = 0.035), compared with patients with shift (139.2 vs . 145.2, P = 0.935) and patients without screw malposition. More than half of the screw malposition was observed at the upper instrumented vertebra. At the upper instrumented vertebra, if the screw's overlap to the bone surface at the insertion point was decreased, skive was more likely (57% vs . 87%, P < 0.001). No patients were returned to the operating room for screw revision.

CONCLUSIONS

Intraoperative screw malposition occurred in 2.4% of RA-CBT. High body mass index was associated with screw malposition, regardless of etiology. Skive was associated with high HU and decreased screw overlap to the bone surface at the insertion point.

Risk Factors for Medial Breach During Robotic-Assisted Cortical Bone Trajectory Screw Insertion

OBJECTIVE

We describe the incidence of, and identify the risk factors for, a medial breach of the pedicle wall during robotic-assisted cortical bone trajectory (RA-CBT) screw insertion.

METHODS

We analyzed a consecutive series of adult patients who underwent RA-CBT screw placement from January 2019 to July 2022. To assess the pedicle wall medial breach, postoperative computed tomography (CT) images were analyzed. Patient demographic data and screw data were compared between patients with and without a medial breach. The Hounsfield units (HUs) on the L1 midvertebral axial CT scan was used to evaluate bone quality.

RESULTS

Of 784 CBT screws in 145 patients, 30 (3.8%) had a medial breach in 23 patients (15.9%). One screw was grade 2, and the others were grade 1. Patients with a medial breach had a lower HU value compared with the patients without a medial breach (123.3 vs. 150.5; P = 0.027). A medial breach was more common in the right than left side (5.5% vs. 2.0%; P = 0.014). More than one half of the screws with a medial breach were found in the upper instrumented vertebra (UIV) compared with the middle construct or lowest instrumented vertebra (6.7% vs. 1.3% vs. 2.7%; P = 0.003). Binary logistic regression showed that low HU values, right-sided screw placement, and UIV were associated with a medial breach. No patients returned to the operating room for screw malposition. No differences were found in the clinical outcomes between patients with and without a medial breach.

CONCLUSIONS

The incidence of pedicle wall medial breach was 3.8% of RA-CBT screws in the postoperative CT images. A low HU value measured in the L1 axial image, right-sided screw placement, and UIV were associated with an increased risk of medial breach for RA-CBT screw placement.

Opioid-sparing Anesthesia Decreases In-hospital and 1-year Postoperative Opioid Consumption Compared With Traditional Anesthesia: A Propensity-matched Cohort Study

STUDY DESIGN

Propensity-matched cohort.

OBJECTIVE

The aim of this study was to determine if opioid-sparing anesthesia (OSA) reduces in-hospital and 1-year postoperative opioid consumption.

SUMMARY OF BACKGROUND DATA

The recent opioid crisis highlights the need to reduce opioid exposure. We developed an OSA protocol for lumbar spinal fusion surgery to mitigate opioid exposure.

MATERIALS AND METHODS

Patients undergoing lumbar fusion for degenerative conditions over one to four levels were identified. Patients taking opioids preoperatively were excluded. OSA patients were propensity-matched to non-OSA patients based on age, sex, smoking status, body mass index, American Society of Anesthesiologists grade, and revision versus primary procedure. Standard demographic and surgical data, daily in-hospital opioid consumption, and opioid prescriptions 1 year after surgery were compared.

RESULTS

Of 296 OSA patients meeting inclusion criteria, 172 were propensity-matched to non-OSA patients. Demographics were similar between cohorts (OSA: 77 males, mean age=57.69 yr; non-OSA: 67 males, mean age=58.94 yr). OSA patients had lower blood loss (326 mL vs. 399 mL, P =0.014), surgical time (201 vs. 233 min, P <0.001) emergence to extubation time (9.1 vs. 14.2 min, P< 0.001), and recovery room time (119 vs. 140 min, P =0.0.012) compared with non-OSA patients. Fewer OSA patients required nonhome discharge (18 vs. 41, P =0.001) compared with the non-OSA cohort, but no difference in length of stay (90.3 vs. 98.5 h, P =0.204). Daily opioid consumption was lower in the OSA versus the non-OSA cohort from postoperative day 2 (223 vs. 185 morphine milligram equivalents, P =0.017) and maintained each day with lower total consumption (293 vs. 225 morphine milligram equivalents, P =0.003) throughout postoperative day 4. The number of patients with active opioid prescriptions at 1, 3, 6, and 12 months postoperative was statistically fewer in the OSA compared with the non-OSA patients.

CONCLUSIONS

OSA for lumbar spinal fusion surgery decreases in-hospital and 1-year postoperative opioid consumption. The minimal use of opioids may also lead to shorter emergence to extubation times, shorter recovery room stays, and fewer discharges to nonhome facilities.

The treatment of deep shoulder infection and glenohumeral instability with debridement, reverse shoulder arthroplasty and postoperative antibiotics

We retrospectively reviewed 21 patients (22 shoulders) who presented with deep infection after surgery to the shoulder, 17 having previously undergone hemiarthroplasty and five open repair of the rotator cuff. Nine shoulders had undergone previous surgical attempts to eradicate their infection. The diagnosis of infection was based on a combination of clinical suspicion (16 shoulders), positive frozen sections (> 5 polymorphonuclear leukocytes per high-power field) at the time of revision (15 shoulders), positive intra-operative cultures (18 shoulders) or the pre-operative radiological appearances. The patients were treated by an extensive debridement, intravenous antibiotics, and conversion to a reverse shoulder prosthesis in either a single- (10 shoulders) or a two-stage (12 shoulders) procedure. At a mean follow-up of 43 months (25 to 66) there was no evidence of recurrent infection. All outcome measures showed statistically significant improvements. Mean abduction improved from 36.1 degrees (sd 27.8) pre-operatively to 75.7 degrees (sd 36.0) (p < 0.0001), the mean forward flexion from 43.1 degrees (sd 33.5) to 79.5 degrees (sd 43.2) (p = 0.0003), and mean external rotation from 10.2 degrees (sd 18.7) to 25.4 degrees (sd 23.5) (p = 0.0037). There was no statistically significant difference in any outcome between the single-stage and the two-stage group.

Genetic differentiation between mallee and tree forms in the Eucalyptus loxophleba complex

The Eucalyptus loxophleba complex comprises two tree taxa (E. loxophleba ssp. loxophleba and ssp. supralaevis), two mallee taxa (E. loxophleba ssp. lissophloia and ssp. gratiae), and three rare mallee species, of which one, E. blaxellii, is included in this study. The genetic diversity and phylogenetic relationships between the taxa, particularly in relation to habit, were assessed using anonymous nuclear RFLP loci. The level of diversity in the taxa was high and similar to that detected in other eucalypt species. The populations showed low differentiation at both the subspecies and the species levels. Phylogenetic relationships showed some genetic separation between the tree and mallee habit but no separation of the two taxa within the tree habit or within the mallee habit. The genetic analysis does not support the recognition of E. gratiae as a separate species. The geographically restricted E. blaxellii showed similar levels of diversity to populations of the other widespread taxa of E. loxophleba.

Arterial occlusion after surgery for ovarian malignancy. A case report

BACKGROUND

Inherent in the risks of pelvic surgery is the postoperative morbidity and mortality associated with the procedure. The gynecologic oncology patient presents further risks for several reasons, including a relative state of hypercoagulability. Anticipation of the problem and early recognition are the keys to decreasing the long-term sequelae of a complication. A well-recognized complication of gynecologic oncology surgery is venous thromboembolism. Advances allow the prophylaxis, recognition and treatment of this problem. Acute arterial occlusion is a much less common but potentially devastating complication.

CASE

A woman underwent surgery for ovarian malignancy and developed bilateral arterial occlusion of the lower extremities postoperatively.

CONCLUSION

Understanding the various genetic defects that predispose certain individuals to hypercoagulability will help identify patients with a particularly high risk of developing acute arterial occlusive disease.

High-throughput SNP genotyping with the Masscode system

QIAGEN Genomics, Inc, has developed the Masscode tagging system for DNA labeling and detection. In this application, the Masscode system is described as applied to high-throughput single-nucleotide polymorphism (SNP) genotyping. The labeling system is based on a small-molecular-weight tag that is covalently attached through a photocleavable linker to a DNA oligonucleotide. The tagged oligonucleotide is used as a primer in an allele-specific PCR SNP discrimination assay. The allele-specific amplicons are differentiated through their Masscode tag assignments. After a photolysis step to cleave the tags from the amplicon, the samples are introduced into a single quadrupole mass spectrometry detection system for analysis. Genotyping determinations are based on the relative proportions of the paired allele tags. The system has a lower limit of detection in the femtomolar range (10(-15) M). At present, 30 different Masscode tags may be used simultaneously in a multiplex fashion to routinely provide more than 40,000 SNP genotyping measurements daily. Further developments will allow for the simultaneous detection of several hundred tags.

Hormonal therapy for sows weaned during fall and winter

Sows from five commercial herds were weaned in the fall and winter and used to ascertain the potential application of hormonal therapy to stimulate subsequent litter size born. At weaning sows within parity (1, 2, and 3 through 6) and lactation length classification (early weaned, < or = 14 d; conventionally weaned, > 14 d) were randomly assigned to treatment. Treatments were injection with P.G. 600 (400 IU PMSG with 200 IU hCG) at weaning or no treatment. Sows were individually observed for estrus and mated following protocol for each herd. Breeding, culling, and farrowing data were collected. Treatment with P.G. 600 did not change subsequent rebreeding performance for sows at parity 1 or parities 3 through 6. However, conventionally weaned parity-2 sows treated with P.G. 600 were more likely (P < .05) to return to estrus than conventionally weaned controls (99.0 vs 93.6%, respectively). For parity-1 and parity-2 sows, treatment did not significantly change the likelihood for farrow percentage. However, the likelihood to farrow a litter was greater (P < .05) among P.G. 600-treated sows at parities 3 to 6 that were conventionally weaned (84.4 vs 71.3%, respectively). Subsequent litter birth weight for parity-1 sows treated with P.G. 600 was lower (P < .02) than for controls (15.6 vs 16.6 kg, respectively). Subsequent litter size at birth was not affected by treatment for parity-1 or parity-2 sows compared with controls. However, early-weaned sows at parities 3 through 6 treated with P.G. 600 had more (P < .06) total number born than controls (12.4 vs 10.6, respectively). Treatment with P.G. 600 improved reproductive function within specific parity and lactation length classification for sows weaned in the fall and winter.

An overview of proteinase inhibitors

Proteinase inhibitors are proteins in the body that regulate the catalytic activity of proteinases. They are important in a large variety of physiologic processes including coagulation, digestion, tumor metastasis and immunity. Proteinase inhibitors are categorized as either nonspecific proteinase inhibitors or class-specific proteinase inhibitors. Nonspecific proteinase inhibitors are comprised soley of the alpha macroglobulins, most notably alpha2-macroglobulin. Class-specific proteinase inhibitors are subcategorized as serine proteinase inhibitors, aspartic proteinase inhibitors, metalloproteinase inhibitors, and cysteine proteinase inhibitors. Each subcategory is made up of numerous inhibitors. As the roles of individual proteinase inhibitors are determined, the therapeutic use of natural and synthetic proteinase inhibitors is also being investigated. The purpose of this article is to review the history and classification of proteinase inhibitors and their relevance to veterinary medicine.

Health policy on the town meeting agenda

American Health Decisions, a movement that started in Oregon, has spread to several other states. Through the media and widespread public discussion, the projects aim to increase public awareness about the individual and societal dimensions of ethical choices in health care.

Oregon Health Decisions. An experiment with informed community consent

Oregon Health Decisions is a citizen-based project intended to develop statewide awareness of severe bioethical dilemmas. The project has set in motion civic means for addressing and resolving problems in Oregon's health provision system associated with personal autonomy, equity of access, prevention of illness, and humane cost containment. The process of civic involvement with consequent results is described together with the implications for future health policy in Oregon and elsewhere.