Intraoperative Errors Research Articles

Extracapsular hip fractures: fixation with a twin hook or a lag screw?

The twin hook, which has 2 oppositely directed apical hooks, is an alternative to the lag screw for use with a 'dynamic plate' in the fixation of trochanteric hip fractures. In this prospective study lasting 1 year, 102 consecutive patients with trochanteric hip fractures were treated by 19 surgeons with either a twin hook or a lag screw combined with a conventional sliding hip screw plate or a Medoff sliding plate. Seven intraoperative errors were made with the twin hook but postoperative migration did not differ significantly between the 2 groups. Postoperative fixation failures were equally distributed between the 2 groups. The twin hook provides adequate fixation, which is comparable to that produced by a lag screw.

Image-guided spinal surgery: Technology, operative technique, and clinical practice

The complications associated with misplaced pedicle screws are mostly neurological or vascular. Previous studies of surgical procedures have shown a significant rate of incorrect placement of pedicle screws, ranging from 15% to 40%. To increase the safety of screw placement, a technique that combines preoperative computed tomography (CT) imaging with intraoperative passive navigation is proposed. A combination of registration algorithms is used to match the preoperative model of the vertebra with intraoperative points that are obtained by using a pointer and a 3-dimensional optical localizer. Images and optimal trajectories are then reported in the intraoperative space. The tip and axis of any surgical tool or guide is visualized in real-time in the volume of preoperative CT images to perform the computer-assisted drilling procedure. Ninety-six pedicle screws have been inserted in lumbar and thoracic vertebrae (from T10 to L5) for various spine disorders with the computer-assisted system. Surgery was followed by postoperative radiographs and CT scans, on which measurements of screw position relative to pedicle could be performed. Nine percent to 12% penetration is obtained with the computer-assisted technique; 44% is obtained with the manual insertion. Preoperative errors from the CT scan data (image gap) and intraoperative errors that occur during the collecting of point coordinates may explain the computer-assisted technique failures. The results clearly show that the computer-assisted surgery technique provides much better safety and accuracy than manual insertion. This technology is evolving rapidly and many new extensions will occur in the years to come.

Neural network pattern recognition analysis of graft flow characteristics improves intra-operative anastomotic error detection in minimally invasive CABG.

The intra-operative assessment of the quality of anastomosis in minimally invasive coronary artery bypass surgery (CABG) is critical. Recent investigations demonstrated that flow probes used intra-operatively to assess anastomotic errors may give the surgeon a false sense of confidence as only severely stenotic anastomoses (>90%) could be reliably detected. We developed a neural network system using graft flow data and assessed its potential to improve anastomotic error detection. Mammary to LAD grafts (n = 46) were constructed in mongrel dogs off-pump. Continuous beat-to-beat graft flow was recorded using transit-time flow probes. Various degrees of anastomotic stenoses (0-100%) were created by an additional suture. The degree of anastomotic stenosis was confirmed by postoperative angiography. A learning vector quantization neural network was created using heart rate, mean aortic pressure, mean systolic, maximum systolic, minimum systolic, mean diastolic, maximum diastolic, minimum diastolic, and mean graft flows. In addition, a spectral analysis of the flow waveforms was performed and the magnitude and phase of the first five harmonics were used to further develop the neural network. The neural network pattern recognition system was 94% accurate in detecting any stenosis >50%. To validate the model, a testing set was used with 20% of the data values, and the accuracy remained at 100% above chance alone. Pattern recognition of transit-time flow probe tracings using neural network systems can detect anastomotic errors significantly better than the surgeon's visual assessment, thereby improving the clinical outcome of minimally invasive CABG.

Pitfalls in the surgical management of cervical spine injuries.

Records of 69 cervical spine injury patients referred to the authors' institution over a 3-year period were reviewed. The senior author documented "definite" and "probable" pitfalls occurring in the pre-, intra-, and postoperative management. Diagnosis, traction, bracing, surgical timing, intraoperative technical errors, and incorrect surgical decisions were noted. Of the 69 patients, 39 (56%) suffered a pitfall of management. Twenty-seven patients (39%) accumulated 49 "definite" pitfalls between them and 12 patients (17%) suffered a total of 20 "probable" pitfalls. Of the 49 definite pitfalls, 7 (14%) were preoperative, 17 (34%) were those of surgical decision making, 21 (43%) were operative, and 4 (9%) postoperative. Diagnostic errors and incorrect bracing and traction led to neurological worsening. Intraoperatively, technical errors (30%), wrong timing of surgery (24%), and incorrect choice of operation (16%) were the common pitfalls. Postoperative pitfalls consisted of inappropriate bracing (17%). A Cervical Spine Research Society review (1989) rated complications of cervical spine surgery at 6.3% (63/992). In this study, a sizeable portion (56%) of cervical spine injury patients requiring surgery were at a risk of complications. Short of complications, there are areas of management where errors may have less well-documented undesirable effects or increase the potential for morbidity. An awareness of these pitfalls and increased use of non-operative treatment may eliminate up to 73% of the pitfalls and thereby decrease the morbidity associated with the management of cervical spine injuries.

Intraoperative duplex scanning as a means of quality control during carotid endarterectomy

To identify correctable technical errors following carotid endarterectomy using intraoperative colour duplex sonography (ATL, UM9, HDI). Results were compared with intraoperative flow measurements using an operative flow meter and with middle cerebral artery velocity measured by trans-cranial Doppler (TCD). Prospective study. 50 consecutive patients undergoing carotid endarterectomy were investigated. Follow-up was performed at 6 weeks using duplex scanning and clinical evaluation. Significant intraoperative technical errors were detected in three patients and were re-explored. Two scans demonstrated kinking or pinching at the distal endarterectomy site requiring patch-plasty and the third revealed a large mass of intramural thrombus. A further 18 endarterectomies yielded 21 additional minor abnormalities. Duplex sonography provides a sensitive intraoperative technique for detecting thrombus and technical errors. It yields both anatomic and hemodynamic details and is superior to intraoperative flow measurements and transcranial doppler.

Rush rod fixation of supracondylar fractures above total knee arthroplasties

The authors report on 22 displaced supracondylar femur fractures and total knee arthroplasties treated with Rush rod (Berivon, Meridian, MI) fixation. The average age at the time of total knee arthroplasty was 67 years. Fractures occurred at an average of 5 years after surgery. In only five cases was a notch in the anterior cortex noted. The follow-up period averaged 7 years. There were no nonunions. All knees healed between 3 and 4 months after surgery. Postoperative flexion averaged 108° (preoperative average, 102°). Only two knees demonstrated a flexion contracture before surgery (5°–10°), and both had flexion contractures after surgery as well (each 10°). All other knees achieved full extension. The average alignment prior to fracture was 7° of anatomic valgus. At the most recent follow-up evaluation this averaged 10° with two knees in 15° of valgus. The only complications noted were two intraoperative technical errors. No postoperative complications occurred. For supracondylar fractures above a total knee arthroplasty, the authors suggest closed reduction, Rush supracondylar rod fixation, early range of motion, and protected weight bearing until fracture healing. In all cases, an extensive surgical procedure was not required.

Extraarticular Subtalar Arthrodesis: The Dowel Method

The technique and results of extraarticular subtalar arthrodesis using the dowel method during the 10-year period between 1976 and 1986 were reviewed retrospectively. Fifty feet in 30 children underwent extraarticular subtalar arthrodesis for valgus deformity for diagnoses including meningomyelocele, idiopathic flatfoot, and cerebral palsy. The aims of the procedure were to correct the deformity, obtain a solid arthrodesis, and improve ambulation by reducing bracing requirements and eliminating pain. Results were excellent in 28 cases (56%), satisfactory in 15 (30%), and unsatisfactory in seven (14%). Intraoperative positioning error and simultaneous perineal tendon lengthening in children with cerebral palsy were the major sources of unsatisfactory results.

Femoral Endoprosthesis Fixation With a Soft, Flexible Low Modulus Stem Coating Four to Six Year Clinical Results

Fifty-nine patients received 62 femoral endoprostheses exhibiting a 2 mm thick, low modulus (soft), porous stem coating in a total hip arthroplasty. Follow up ranged from 36 to 69 months (average 60 months). There were 26 male and 33 female patients whose ages ranged from 29 to 75 and 39 to 72 years, respectively (average 57 years). All patients were operated on without trochanteric osteotomy. Initial stabilization was obtained by uniform press-fit and collar/neck osteotomy contact at implantation; secondary stabilization derived from soft tissue ingrowth into the stem coating. Four implants in four patients were deleted from the scored population because of unrelated deaths or loss to follow up. By the Harris scoring system, 48 of the 58 implants (82.7%) were rated excellent or good, 58.6% and 24.1% respectively. Seven were rated poor (12.1%), of which six (10.3%) have been revised. Other revisions included one hip for secondary sepsis (1.7%), one post-traumatic fracture (1.7%), and one intraoperative technical error (1.7%).

Complications encountered with the use of the Greenfield filter

The Greenfield filter can be used with a low complication rate provided one adheres to certain principles. First, preoperative venography to define the inferior vena caval anatomy will help avoid difficulties associated with anatomic variations. At the time the study is carried out, it would be extremely useful if the radiologist places a radiopaque marker at the level of the renal veins. This will ensure that filters will be placed in the infrarenal position when appropriate, thus preventing occasional inadvertent discharge, particularly into the right renal vein. Second, use of a guide wire greatly facilitates passage of the introducer and accurate intracaval positioning. Third, intraoperative technical errors must be recognized and promptly corrected. Finally, meticulous postoperative follow-up is essential, and recurrent embolism or any change in filter position requires repeat roentgenography of the vena cava to guide appropriate corrective treatment.

Determinants of failure in the treatment of ruptured abdominal aortic aneurysm.

One must identify those fatal errors in the treatment of patients with ruptured abdominal aortic aneurysms (AAAs) to improve future treatment and reduce mortality. Our vascular registry identified 29 patients with ruptured AAAs who died following admission to the UCLA Hospital, Los Angeles, and the Sepulveda (Calif) Veterans Administration Hospital between 1971 and 1981. Review of the records identified four categories of error that contributed to death. These included failure to proceed with elective aneurysmectomy in 12 patients with known AAAs, error in the diagnosis of aortic rupture that led to delay in getting nine patients to the operating room, intraoperative technical error that produced venous injury in eight patients, and undue delay in anesthetic induction in four patients. Following the outline of a careful treatment approach should further reduce the mortality in the treatment of patients with ruptured AAAs.

Acute Limb Ischemia Following Aortic Reconstruction

Acute limb ischemia following aortic reconstruction is primarily related to intraoperative technical errors and is associated with significantly increased mortality. Elective aortic reconstruction was performed on 262 patients between 1975 and 1981. Surgical indications were aneurysm in 84 patients (32%), occlusive disease in 125 (48%), and both of these in 53 (20%). Acute limb ischemia developed postoperatively in 27 patients (10.3%); it was noted at the conclusion of the operation in five (19%) of them and within the first 48 hours in 22 (81%). The mortality was greater in the combined aneurysm and occlusive disease group than in the aneurysm-only and occlusive disease-only groups, primarily because of an increased incidence of myocardial disease in the combined group. Postoperative limb ischemia was mainly a result of technical error and resulted in increased mortality in all groups.

Infrarenal Aortic Aneurysmectomy

The complications of major vascular surgery are closely allied with intraoperative technical errors. Thus, in this article, surgical management is carefully described, with special stress given to those details in which complications can be avoided. The complications of infrarenal aortic aneurysmectomy are discussed, emphasizing incidence, cause, diagnosis, management, and results.

Mitral defects with constrictive pericarditis. Possible preoperative and intraoperative diagnostic errors

Zunachst wird darauf hingewiesen, das gleichzeitiges Vorliegen von Pericarditis constrictiva und rheumatischen Erkrankungen der Mitralklappe in etwa 110/0 der Falle von Panzerherz zu erwarten ist. Eine praoperative Fehlbeurteilung ist dadurch leicht moglich, weil der eine Herzfehler die Symptome des anderen verdeckt oder auch die Hamodynamik entscheidend verandert. Besonders ders gilt dies fur Sonderformen der Pericarditis constrictiva, deren Symptome weitgehend reinen Klappenstenosen entsprechen konnen. Wegen der hohen Letalitat der Perikardresektion bei Bestehen von Mitralvitien kommt der intraoperativen Beurteilung und im gegebenen Fall sofortigen Korrektur des Mitralfehlers groste Bedeutung zu.