What Is the Expected Learning Curve in Computer-assisted Navigation for Bone Tumor Resection?

Background

Computer navigation during surgery can help oncologic surgeons perform more accurate resections. However, some navigation studies suggest that this tool may result in unique intraoperative problems and increased surgical time. The degree to which these problems might diminish with experience–the learning curve–has not, to our knowledge, been evaluated for navigation-assisted tumor resections.

Questions/purposes

(1) What intraoperative technical problems were observed during the first 2 years using navigation? (2) What was the mean time for navigation procedures and the time improvement during the learning curve? (3) Have there been any differences in the accuracy of the registration technique that occurred over time? (4) Did navigation achieve the goal of achieving a wide bone margin?

Methods

All patients who underwent preoperative virtual planning for tumor bone resections and operated on with navigation assistance from 2010 to 2012 were prospectively collected. Two surgeons (GLF, LAA-T) performed the intraoperative navigation assistance. Both surgeons had more than 5 years of experience in orthopaedic oncology with more than 60 oncology cases per year per surgeon. This study includes from the very first patients performed with navigation. Although they did not take any formal training in orthopaedic oncology navigation, both surgeons were trained in navigation for knee prostheses. Between 2010 and 2012, we performed 124 bone tumor resections; of these, 78 (63%) cases were resected using intraoperative navigation assistance. During this period, our general indications for use of navigation included pelvic and sacral tumors and those tumors that were reconstructed with massive bone allografts to obtain precise matching of the host and allograft osteotomies. Seventy-eight patients treated with this technology were included in the study. Technical problems (crashes) and time for the navigation procedure were reported after surgery. Accuracy of the registration technique was defined and the surgical margins of the removed specimen were determined by an experienced bone pathologist after the surgical procedure as intralesional, marginal, or wide margins. To obtain these data, we performed a chart review and review of operative notes.

Results

In four patients (of 78 [5%]), the navigation was not completed as a result of technical problems; all occurred during the first 20 cases of the utilization of this technology. The mean time for navigation procedures during the operation was 31 minutes (range, 11–61 minutes), and the early navigations took more time (the regression analysis shielded R² = 0.35 with p < 0.001). The median registration error was 0.6 mm (range, 0.3–1.1 mm). Registration did not improve over time (the regression analysis slope estimate is ?0.014, with R² = 0.026 and p = 0.15). Histological examinations of all specimens showed a wide bone tumor margin in all patients. However, soft tissue margins were wide in 58 cases and marginal in 20.

Conclusions

We conclude that navigation may be useful in achieving negative bony margins, but we cannot state that it is more effective than other means for achieving this goal. Technical difficulty precluded the use of navigation in 5% of cases in this series. Navigation time decreased with more experience in the procedure but with the numbers available, we did not improve the registration error over time. Given these observations and the increased time and expense of using navigation, larger studies are needed to substantiate the value of this technology for routine use.

Level of Evidence

Level IV, therapeutic study.

     

What Is the Quality of Pre-Dialysis Healthcare in the Czech Republic?

Aim: The PREPARE study (PRE-dialysis healthcare in PAtients initiating Renal rEplacement therapy and its consequences) evaluates the quality of pre-dialysis healthcare in patients commencing dialysis treatment in the Czech Republic. Methods: 48% of Czech dialysis centers participating in this prospective multicenter observational study provided data on all consecutive patients starting renal replacement therapy during 24 weeks. Results: 68% out of 303 patients had nephrological pre-dialysis care lasting >6 months (57% diabetics). Peritoneal dialysis (PD) was chosen by 11.2%. 23.6% of patients were receiving erythropoiesis-stimulating agents while the mean hemoglobin level was 98.3 ±15.6 g/l. 36.1% of patients were taking phosphate binders while serum phosphates reached 1.90 ±0.61 mmol/l. 64.4% of patients had a functional arteriovenous fistula or PD catheter. 91.8% of the patients felt they were well informed about hemodialysis and 51.6% about PD. Physicians reported poor compliance of patients in 15.1% of cases, while the patients evaluated their own compliance as 9.4%. Conclusions: To conclude: (1) better pre-dialysis care and information are needed; (2) higher awareness on PD might increase its low popularity; (3) particular attention should be paid to diabetics due to their higher morbidity, a lower proportion considered for transplantation and a lower proportion referred to nephrologists by diabetologists, and (4) preemptive transplantation should be considered more often.     

Ulnar Nerve Innervation of the Triceps Muscle: Real or Apparent? An Anatomic Study

Background

Since the 18th century, the existence of ulnar nerve innervation of the medial head of the triceps brachii muscle has been controversial. The evidence for or against such innervation has been based on macroscopic dissection, an unsuitable method for studying intraneural topography or intramuscular branching. The study of smaller specimens (embryos or fetuses) by means of serial histologic sections may resolve the controversy.

Questions/Purposes

Using fetal specimens and histology we determined the contributions of the ulnar and radial nerves to innervation of the triceps brachii muscle.

Methods

We histologically examined 15 embryonic and fetal arms. Radial nerve branches obtained from six adult arms were analyzed immunohistochemically to determine motor fiber content.

Results

The medial head of the triceps brachii muscle was always innervated by the radial nerve (ulnar collateral branch). The branches seeming to leave the ulnar nerve at elbow level were the continuation of the radial nerve that had joined the ulnar nerve sheath via a connection in the axillary region. Immunohistochemistry revealed motor and nonmotor fibers in this radial nerve branch.

Conclusions

A connection between the radial and ulnar nerves sometimes may exist, resulting in an apparent ulnar nerve origin of muscular branches to the medial head of the triceps, even though in all our specimens the fibers could be traced back to the radial nerve.

Clinical Relevance

Before performing or suggesting new muscle and nerve transpositions using this apparent ulnar innervation, the real origin should be confirmed to avoid failure.     

What Is the Risk of Clinical Anastomotic Leak in the Diverted Colorectal Anastomosis?

Objective

The objective of this study was to identify clinical leak in diverted colorectal anastomoses.

Design

Cohort analysis.

Setting

The study was conducted in a subspecialty practice at a tertiary care facility.

Patients

Consecutive subjects undergoing colorectal anastomosis and proximal fecal diversion between July 16, 2007 and June, 31 2012.

Interventions

No intervention was applied.

Main Outcome Measures

Clinical anastomotic leak.

Results

Two hundred forty-five patients underwent a colorectal anastomosis with proximal fecal diversion. A total of 34 (14 %) clinical leaks were identified at a median of 43 days. Clinical leaks were identified in 13 (5 %) patients within 30 days of surgery (early leaks) and in 21 (9 %) patients after 30 days of surgery (late leaks). Age, sex, use of neoadjuvant chemoradiotherapy, and method of anastomotic construction were similar in patients with clinical leaks as compared to those with no evidence of leak. However, clinical leaks were more likely to develop in patients with a diagnosis of inflammatory bowel disease or other diagnoses, i.e., radiation enteritis, ischemia, and injury/enterotomy. Patients with clinical leak were not more likely to have air leaks on intraoperative air leak testing.

Conclusions

In diverted anastomoses, most leaks become clinically apparent beyond 30 days. The standard practice of censoring outcomes that occur beyond postoperative day 30 will fail to identify a substantial fraction of leaks in diverted colorectal anastomoses.     

Is the Standard of Care What We Think It Is?

For the most part, gynecologists are actually unaware of the issues involving surrogate versus quality of life outcomes, the "deceptive practice of medicine" and the true incidence of complications as they relate to the standard of care. An anonymous survey of 1958 practicing gynecologists attending seven national symposia revealed a significant number of unreported complications. Clearly, the standard of care (at least with regard to complication risk) is markedly different than has been suggested by the medical literature. Concomitantly, we suggest that physicians need to take a more active role in the policing of our own specialties.     

What Is the Impingement-free Range of Motion of the Asymptomatic Hip in Young Adult Males?

BackgroundFemoroacetabular impingement is a recognized cause of chondrolabral injury. Although surgical treatment for impingement seeks to improve range of motion, there are very little normative data on dynamic impingement-free hip range of motion (ROM) in asymptomatic people. Hip ultrasound demonstrates labral anatomy and femoral morphology and, when used dynamically, can assist in measuring range of motion.Questions/purposesThe purposes of this study were (1) to measure impingement-free hip ROM until labral deflection is observed; and (2) to measure the maximum degree of sagittal plane hip flexion when further flexion is limited by structural femoroacetabular abutment.MethodsForty asymptomatic adult male volunteers (80 hips) between the ages of 21 and 35 years underwent bilateral static and dynamic hip ultrasound examination. Femoral morphology was characterized and midsagittal flexion passive ROM was measured at two points: (1) at the initiation of labral deformation; and (2) at maximum flexion when the femur impinged on the acetabular rim. The mean age of the subjects was 28 ± 3 years and the mean body mass index was 25 ± 4 kg/m².ResultsMean impingement-free hip passive flexion measured from full extension to initial labral deflection was 68° ± 17° (95% confidence interval [CI], 65–72). Mean maximum midsagittal passive flexion, measured at the time of bony impingement, was 96° ± 6° (95% CI, 95–98).ConclusionsUsing dynamic ultrasound, we found that passive ROM in the asymptomatic hip was much less than the motion reported in previous studies. Measuring ROM using ultrasound is more accurate because it allows anatomic confirmation of terminal hip motion.

Clinical Significance

Surgical procedures used to treat femoroacetabular impingement are designed to restore or increase hip ROM and their results should be evaluated in light of precise normative data. This study suggests that normal passive impingement-free femoroacetabular flexion in the young adult male is approximately 95°.