Computer-assisted surgery in orthopedic oncology: Technique,indications, and a descriptive study of 130 cases

Background and purpose —

In orthopedic oncology, computer-assisted surgery (CAS) can be considered an alternative to fluoroscopy and direct measurement for orientation, planning, and margin control. However, only small case series reporting specific applications have been published. We therefore describe possible applications of CAS and report preliminary results in 130 procedures.

Patients and methods —

We conducted a retrospective cohort study of all oncological CAS procedures in a single institution from November 2006 to March 2013. Mean follow-up time was 32 months. We categorized and analyzed 130 procedures for clinical parameters. The categories were image-based intralesional treatment, image-based resection, image-based resection and reconstruction, and imageless resection and reconstruction.

Results —

Application to intralesional treatment showed 1 inadequate curettage and 1 (other) recurrence in 63 cases. Image-based resections in 42 cases showed 40 R0 margins; 16 in 17 pelvic resections. Image-based reconstruction facilitated graft creation with a mean reconstruction accuracy of 0.9 mm in one case. Imageless CAS was helpful in resection planning and length- and joint line reconstruction for tumor prostheses.

Interpretation —

CAS is a promising new development. Preliminary results show a high number of R0 resections and low short-term recurrence rates for curettage.Oncological surgical treatment can be considered to be a trade-off between margins and function, with margins being the most important factor to consider. Accuracy is needed to achieve an efficient but oncologically safe result. To assist in this, most procedures in bone tumor surgery require intraoperative imaging with fluoroscopy and/or measurements with rulers for anatomical orientation and margin control. The best examples of this are pelvic resections. Cartiaux et al. (2008) demonstrated that 4 experienced surgeons could achieve a 10-mm resection margin, with 5-mm tolerance, on pelvic sawbones in only half of the resections. The supportive imaging and measuring modalities have, however, remained more or less unchanged for many years. In a 2-dimensional (2D) workflow such as fluoroscopy, there is still the requirement for an accurate frame of reference based on anatomical landmarks for adequate 3-dimensional (3D) margin control.In recent years, the use of computer-assisted surgery (CAS) in orthopedic surgery has become more common as an alternative for intraoperative imaging and measurements, providing the necessary precision in bone tumor surgery. The technique that is mostly used in orthopedic oncology is image-based navigation. The patient’s own anatomy (MRI and/or CT) is entered into the system and used during surgery. This provides real-time, continuous, 3D imaging feedback and may lead to more precise margin control, better tissue preservation, and new approaches to reconstruction while remaining oncologically safe. Several publications have supported CAS as being a safe navigation platform for planning and performing resections (Wong et al. 2007, So et al. 2010, Cho et al. 2012). A recent publication describes lessons in the technological approach and offers comments on CAS workflow (Wong 2010). However, to date the largest case series have involved only 20 and 31 cases (Cheong and Letson 2011, Jeys et al. 2013). The reported use has mostly been limited to complex tumor resections (e.g. pelvic), and due to the novelty of the technique, applications, approaches, and set-up times differ greatly (Saidi 2012). Here we describe possible applications of CAS in bone tumor surgery (also outside of complex resections), consider their usefulness, and report preliminary results from 130 CAS procedures performed at a single institution.     

The influence of HLA-mismatches on phenotypic and functional characteristics of graft infiltrating lymphocytes after heart transplantation

We studied the influence of HLA mismatches on T lymphocyte cultures that were derived from endomyocardial biopsies (EMB) from 118 heart transplant recipients. From patients with DR mismatches, the majority of the EMB-derived cultures were dominated by CD4, while in patients without DR mismatches, CD8 was the predominant T cell subset. The majority (75) of the cultures were cytotoxic against donor antigens. A significantly (P < 0.005) lower proportion of the cultures showed cytotoxicity (36 %) against HLA-A antigens when compared to HLA-B (53 %) or HLA-DR (49 %). A dose effect phenomenon was detected for all HLA antigens, including HLA-A: a higher number of A, B or DR mismatches resulted in a higher number of cytotoxic cultures directed against these antigens. B and DR matching had the greatest influence on 6 month freedom from rejection. Both our experimental and clinical data indicated that HLA matching played a role in the immune response against a transplanted heart.     

Cold Modalities With Different Thermodynamic Properties Produce Different Surface and Intramuscular Temperatures

OBJECTIVE: To compare surface cooling and deep cooling produced by 3 common forms of cryotherapy. DESIGN AND SETTING: We used a 3 x 4 x 4 factorial with repeated measures on measurement depth and treatment. Independent variables were measurement depth (surface, fat + 1 cm, and fat + 2 cm), treatment (ice bag, Wet-Ice, Flex-i-Cold, and control), and treatment order (first, second, third, and fourth). The lowest temperature recorded was the dependent variable. The treatment order was counterbalanced using a Latin square. Data were analyzed with a repeated-measures analysis of variance. SUBJECTS: Fifteen collegiate volunteers who were free of lower extremity abnormalities. MEASUREMENTS: Thigh skin and thigh intramuscular temperatures (1- and 2-cm subadipose) were measured at 30-second intervals both before and during the 30-minute treatments using fine-wire implantable and surface thermocouples. The coldest recorded temperatures were analyzed. RESULTS: Statistical differences were observed for the depth-by-treatment interaction as well as for the depth and treatment main effects. During cold treatments, superficial depths were colder than deeper depths, and all cold treatments were colder than controls at all depths. For the interaction effect at both the skin surface and at 1-cm subadipose, the ice-bag and Wet-Ice treatments were colder than the Flex-i-Cold treatment. For the interaction at 2-cm subadipose, the cold treatments did not differ from each other. Order of treatments did not produce a significant effect. CONCLUSIONS: During a 30-minute cryotherapy treatment, modalities that undergo a phase change caused lower skin and 1-cm intramuscular temperatures than cold modalities that do not possess these properties. These differences were not seen at 2-cm subadipose but may become apparent with longer treatments.     

Gait in patients with pregnancy-related pain in the pelvis: an emphasis on the coordination of transverse pelvic and thoracic rotations

Objective. To quantify gait impairments in women with pregnancy-related pain in the pelvis which persisted post-partum.

Design. Nine patients and nine healthy subjects were studied during treadmill walking at different velocities.

Background. Walking problems in patients with pregnancy-related pain in the pelvis have been known to exist for a long time. To date, no quantitative gait studies have been conducted in this population.

Methods. Maximum attainable walking velocity was determined, amplitudes of pelvic and thoracic rotations were calculated, and spectral analysis was used to assess the harmonicity of these rotations. Coordination between pelvic and thoracic rotations was characterized as mean relative Fourier phase and weighted coherence.

Results. Maximum attainable walking velocity was highly variable between patients, but on average significantly lower than in healthy controls. Moreover, patients had a significantly lower mean relative Fourier phase (again, highly variable) and higher weighted coherence. The other parameters did not differ significantly between groups.

Conclusions. Coordination between pelvic and thoracic rotations in the transverse plane was affected in patients with pregnancy-related pain in the pelvis. Individual patients may apply different strategies during walking to cope with the underlying problems.Relevance

Pregnancy-related pain in the pelvis is poorly understood. Patients with this condition are known to have problems with locomotion. The present study reveals that gait coordination is altered. Theoretically, this underlines the importance of analysing coordination in pathological movement. Clinically, better understanding the gait problems of women with pregnancy-related pain in the pelvis may contribute to more appropriate treatments.     

A pilot study for one-stop endoscopic total extraperitoneal inguinal hernia repair

Background  

One-stop surgery was developed for patients to undergo surgical evaluation, anesthesia, surgery, and discharge all within 1 day. This study aimed to assess the feasibility, patient satisfaction, and potential of one-stop endoscopic total extraperitoneal (TEP) inguinal hernia surgery.     

Positive blood culture with Plasmodium falciparum: case report

An adult traveler presented with fever and malaise after returning from Sierra Leone. Young trophozoites of Plasmodium falciparum were seen in a blood smear, with parasitemia being 10%. Moreover, blood cultures drawn on admission signaled as "positive" after 1 day of incubation, but no bacteria were seen in the Gram stain or were subcultured. A Giemsa-stained smear from the positive bottle contents yielded numerous pigmented, mature trophozoites of P. falciparum. This case indicates that, in patients with malaria, the growth of P. falciparum in blood cultures can result in "false"-positive blood cultures.     

Chemotherapeutic treatment for spinal tuberculosis.

AIM: To evaluate whether 6 months of chemotherapy for patients with spinal tuberculosis prevents relapse as effectively as more than 6 months of chemotherapy. METHOD: Literature review. Medline search including references, from January 1978 to November 2000. Inclusion criteria for publications: diagnosis of spinal tuberculosis confirmed bacteriologically and/or histologically, or probable on the basis of clinical and radiological parameters; treatment regimen (whether or not in combination with surgery) included isoniazid (H), rifampicin (R) and pyrazinamide (Z); follow-up period after completion of treatment of 12 months or more. Exclusion criteria: patients with relapse who had previously been treated adequately for tuberculosis. OUTCOME PARAMETERS: Relapse rate. RESULTS: Four publications were found with HRZ regimens of 6 months' duration and 10 publications with HRZ regimens of >6 months' duration. A number of patients had received HRE (E = ethambutol) for > or = 9 months. In the results, no distinction was made between treatment groups. HRZ for 6 months led to a relapse rate of 0% (0/56, 95%CI 0.0-6.4); follow-up after surgical intervention ranged from 6 to 108 months. HRZ for > or = 9 months (> or = 119 patients) or HRE for > or = 9 months (< or = 71 patients) led to a relapse rate of 2% (4/218, 95%CI 0.6-5.0); follow-up after surgical intervention was 6-168 months. Despite the small number of studies, 6 months of therapy is probably sufficient for patients with spinal tuberculosis.