Evaluation of the surgical process during joint replacements

Evaluation of the Surgical Process during Joint Replacements.

Man-Machine Systems Group, Department of Médical Technology and Mechanics, Fac. of Design, Engineering and Production, Delft University of Technology, Mekelweg 2,2628 CD Delft,

The Netherlands. Emaihi .minekus(a>wbmt,tudelft.nl

Abstract

A task analysis method has been developed to evaluate joint replacements. Video recordings were made of the surgical process during humeral head, total shoulder and elbow joint replacements. The actions of the surgeon, the scrub technician and the assistant were analysed off-line using a thesaurus of actions. The efficiency was defined as the relative amount of goal-oriented actions of the surgeon. The efficiency of the procedures varied between phases and was on average 61 percent in all three procedures. The main task of the scrub technician was arranging instruments and of the assistant holding clamps. The main shortcomings observed during joint replacements were repeated actions caused by the inability to align the prosthesis at once, and waiting times caused by cement hardening and caused by searching for instruments by the scrub technician.

Keywords: task analysis, surgical team, joint replacement Introduction

In surgery, operative procedures are normally evaluated with respect to the post-operative results. Only few task-analysis studies have been achieved to evaluate the actual surgical process. Those studies were mainly performed in laparoscopic surgery and show that the operative time could be decreased and the efficiency improved (den Boer,K.T., Dankelman,J., Gouma,D.J., and Stassen.L.P., 2002; Joice,P., Hanna,G.B., and Cuschieri,A., 1998). By humeral head replacements a large variations between procedures and a large amount of shortcomings was observed (Minekus,J.P.J., Rozing,P.M., Valstar,E., and Dankelman.J., 2002). There is a demand for more efficient and shorter procedures with less people at the table because of the increased cost, the patient waiting list and the shortage of operating nurses. The goal of our study is to develop a method to evaluate joint replacements by analysing the actions of the surgeon, the assistant and the nurse. From these measurements, the shortcomings and difficulties of the procedure can be determined. We used humeral head, total shoulder and elbow joint replacement in this research.

Method

Surgical procedure:

The surgical procedure of a joint replacement consists of several successive phases:

- preparation phase:

- bone phase:

- test phase:

- closure phase:

Surgical team:

- anaesthesiologist:

- surgeon:

- scrub technician:

- assistant:

This study will focus on the team members working in the sterile area: the surgeon, the scrub-technician and the assistant.

-Table 1 : Thesaurus of functions for the surgeon

Function Definition

Preparing Dissection using e.g. a knife, a rasp, or a saw.

(

o \

Stop bleeding Checking for bleedings and stopping them using coagulating, or swamping.

Observing Watching the wound, palpating or moving the arm. Exposing Placement of hooks to expose the humeral head. "c3

c Waiting Actions that do not contribute to the procedure.

o

Miscellaneous Actions that could not be identified or classified within the

<

Time-action analysis: Video recordings of the procedure were made using two cameras, one giving an

overview of the total operation field and one giving a detailed view of the hands of the surgeon (den Boer,K.T., Dankelman.J., Gouma,D.J., and Stassen,L.P., 2002; Minekus,J.P.J., Rozing,P.M., Valstar,E., and Dankelman,J., 2002). The images with sound were recorded simultaneously using a mixed device and were analysed off-line. The recordings did not interfere with the surgical process; the medical ethical committee of the Leiden University Medical Center approved the research.

The recordings were analysed three times. First, the actions performed by the surgeon were analysed using a thesaurus of 68 actions (MinekusJ.P.J., Rozing,P.M., Valstar,E., and DankelmanJ., 2002). The tokens in the taxonomy have been discussed with the surgeon. In a previous study, performed in laparoscopic surgery, the videos were analyzed by three different observers using a strictly defined taxonomy, showing that there was no difference in results between observers. The actions were grouped to eight different functions (Table 1). The functions preparing, aligning and inserting the prosthesis, and suturing contribute directly to the advancement of the procedure and are, therefore, classified as goal-oriented functions (Minekus,J.P.J., Rozing,P.M., Valstar,E., and Dankelman,J., 2002). The percentage of goal-oriented functions of the surgeon is used as a measure of the efficiency of the operative procedure.

Secondly, the actions of the scrub technician and the assistant were analysed using a thesaurus of functions (Table 2). The thesaurus of the surgeon was expanded with two functions and some functions got a broader meaning. The actions of all three team members can be directed towards the patient (actions like preparing and aligning), towards the instruments (actions like searching for instruments) or towards each other (actions like communication and teaching). Actions are classified as directed towards instruments if the person is solely working with instruments, e.g. cleaning them, or searching for instruments.

Thirdly, the procedures were analysed on the occurrence of shortcomings (Minekus,J.P.J., Rozing,P.M., Valstar,E., and Dankelman,J., 2002). In most procedures, repetitions and corrections are needed due to the complexity of the surgical approach, the limitations of the instruments, or the experience of the surgeon. These repetitions and corrections are called shortcomings. The shortcomings observed during the procedures were grouped into three classes: repeated actions, waiting and miscellaneous.

The functions of the surgeon and the shortcoming are evaluated in 8 humeral head replacements, 4 total shoulder and 11 elbow joint replacements. The actions of the scrub technician and the assistant are evaluated in 10 elbow joint replacements.

-119-Table 2: Thesaurus of functions for the scrub technician and assistant. Function Definition

Preparing Dissecting using e.g. scissors, saws or drills.

Prosthesis Making cement, unpacking the prosthesis or helping to place or align the prosthesis

Suturing Placing sutures or the drain.

Stop bleedings Checking for bleedings and stopping them using e.g. coagulating, or swamping.

Observing Watching the surgeon or the operative process Exposing Placing and holding hooks to expose the joint. Instruments Getting, positioning or cleaning instruments.

Helping Helping the surgeons by actions for, which a third hand is needed.

Waiting Actions that do not contribute to the procedure.

Miscellaneous Actions that could not be identified or classified within the other functions.

Results

All three procedures showed a large variation in duration (Figure 1). The total shoulder replacement has the largest duration, because it is the most complex procedure. The humeral head replacement has the shortest duration, because only one joint part is replaced. The total elbow has the shortest openings phase, because the joint is more superficial and has, therefore, a shorter approach. The total shoulder replacement has the longest bone preparation phase, due to the difficult preparing of the glenoid. The total elbow replacement has the longest prosthesis insertion phase, because two prostheses are placed successively with cement, causing two waiting periods of 10 minutes for the cement to harden. The glenoid component in the total shoulder is also fixated with cement, causing only one waiting period of 10 minutes; the humeral head is placed without cement.

Figure 1 : Average duration of ail phases in 5 total shoulder replacements, 8 humerai head replacements and 11 total elbow replacements. 210 180 '—s G ' 5 150 e o 120 S 90 60 30 0 Total shoulder

EH

-120-Figure 2: Relative duration of functions of the surgeon during total shoulder, humeral head and total elbow replacements. The goal-oriented functions are indicated below the dotted lines. On the X-axis the

phases are indicated. (Also available online: http://www.dcs.gla.ac.uk/~johnson/eam2002 ) Total shoulder Elbow

prepare bone test prosthesis closure prepare bone test prosthesis closure

Humeral head • Miscellaneous • Waiting • Exposing E3 Observing Bl Stop bleeding tH Suturing 0 Prosthesis S Preparing prepare bone prosthesis closure

The surgeon:

The

scrub technician:

The assistant: sometimes uses his hands for two different functions, therefore, these are analysed separately. The main function of the assistant is to hold clamps for exposure (Figure 3, middle bars). Besides holding clamps, the assistant helps the surgeon with preparing, stopping bleedings and suturing. Eighty percent of the actions are directed to the patient, 10 towards the surgeon and 10 percent is spent on waiting. The assistant was a junior surgeon, who had to leam the procedure. Most teaching occurred by observing the surgeon, sometimes the surgeon explained his actions while continuing work

-Figure 3: Average duration of fonctions of the scrub technician and the assistant during ten elbow replacements. On the X-axis the phases are indicated.

(Also available online: http://www.dcs.gla.ac.uk/~johnson/eam2002 )

l expose I stop bleeding • help i l goal oriented m instrument E3 miscleneous S observe^ • wait

The main shortcomings: observed during the procédure were waiting and repeated actions (Table 3). A

shortcoming did not imply a complication: in none of thèse procédures a per-operative complication occurred. The main causes for waiting are the cementing process (10 minutes hardening); unpacking the prosthesis (because the size is determined during the procédure) and waiting for the scrub technician to find the right instruments. Both, waiting for cernent and unpacking the prosthesis, happened in ail procédures during the prosthesis phase. Waiting for the scrub technician occurred several times in ail procédures, especially during the bone and testing phases and is the main cause for the large number of waiting times. The main cause for repeated actions is the difficult alignment of the prosthesis. To align prosthesis, several subséquent steps depending on the prosthesis have to be performed. For most Steps, special alignment instruments exist, which should help the surgeon to align the prosthesis correctly at once. But still up to 6 refinements are needed in 1 step. Some of thèse refinements were even made without the help of an alignment instrument. In ail procédures, at least one repeated action was needed.

Table 3: The total duration of shortcomings in minutes and, between parenthèses, the number of shortcomings per operative procédure. Shortcoming Phase waiting repeated action miscellaneous Total Shoulder 29.4(112) 22.0 (8) 1.0(2) Humera] head 11.1 (53) 7.1 (6) 1.4(2) Total elbow 31.7(76) 17.1 (10) 1.0(2) 1 2 2

-Discussion

Surgical procedures are normally evaluated mainly with respect to post-operative results and complication rate (Alund,M., Hoe-Hansen,C, Tülander,B., Heden,B., and Norlin.R., 2000). These analyses, however, provide hardly any insight into the problems of the actual complex per-operative process. Video analysing of the surgical procedure does give insight into this process. Using task analysis, we showed large variation between procedures and a huge amount of shortcomings during the placement of total elbow, total shoulder and humeral head prostheses. Besides differences in the patient condition and the surgical team, the number of needed repeated actions is the major cause for the observed variations.

Our evaluation method does give insight in the actual surgical process, but it should be used with care (Minekus,J.P.J., Rozing.P.M., Valstar,E., and Dankelman,J., 2002; Sjoerdsma,W., Meijer,D.W., Jansen.A., den Boer,K.T., and Grimbergen.C.A., 2000). The main parameter of time-action analysis, time, is not directly related to the functional outcome. A shorter and more efficient surgical procedure may have less post-operative results and is, therefore, not favourable. The evaluation may also create problems of interpretation, it might look like the nurse is searching when he/she is actually thinking or performing some other cognitive function. In our method, we cannot distinguish cognitive processes from the observations. Finally, the reason of the surgeon for a certain approach or action cannot be determined. By discussing our data with the surgeon, we found that the surgeon was aware of certain limitations and inefficiencies. Some repeated actions were even made on purpose because it improved the accuracy. The surgeon was not aware of all limitations and inefficiencies and after recognising them; the team is trying to reduce them. Therefore, for a good interpretation of the results, interaction with the surgeon is very important.

This study has only evaluated one surgical team using a specific approach and a specific prosthesis. Several approaches are possible to both the shoulder and the elbow joint and different prostheses have different alignment instruments. Different approaches and prostheses have different advantages and disadvantages during the procedure. Also, different operative teams have different cultures. Therefore, we have also analysed some operative procedures by other surgeons. In these procedures, comparable shortcomings and problems could be found.

The two main shortcomings, repeated actions and waiting, have also been found during knee replacements (Dunbar,M.J. and Gross,M., 1995). Repeated actions occur due to the inability to align the prosthesis correctly at once. The number of repeated actions is smaller in knee replacements, because this procedure is more standardised and has different alignment instruments. The waiting time in humeral head, total shoulder, total elbow replacement, and in knee replacements is mainly caused by unwrapping instruments, changing instruments and the cementing process. The comparable shortcomings in different joint replacements show the need of improving the efficiency of joint replacements by for example better alignment instruments, computer guided surgery and faster cementing techniques.

During an elbow joint replacement, most actions were directed towards the patient or the instruments and most communication occurred, e.g. teaching, while the surgeon continued working. Both the surgeon and the scrub technician were experienced and, therefore, not much communication was needed; their tasks were mainly rule based (Rasmussen.J., 1983). A less experienced team may need more communication to discuss the needed instruments or the alignment of the prosthesis. The assistant was an inexperienced junior surgeon and he used these procedures to learn. He had a mainly skill based task, holding clamps given by the surgeon. Possibly a more experienced assistant can take over some actions of the surgeon, thereby reducing the operative time, but further study is needed to confirm this.

Dutch hospitals have a shortage of operating nurses, causing an increase in waiting lists for patients. In non-academic hospitals, the assistant may also be an operating nurse. One person less in the operation theatre may be a partial solution to this shortage. The task of the assistant is mainly holding clamps, which may be done by a technical device. His tasks are then reduced to helping the surgeon and sucking blood, which will take approximately 45 minutes in a procedure. The task of the scrub technician is to cover up the instruments, which is quite complicated because of the large amount of instruments, but the timing is not critical and most work can be done in advance. Also more efficient instrument-tables can be developed, whereby the surgeon can get his own instruments and the non-sterile nurse can do the cleaning after use. This will reduce the work for the scrub technician, so the technician can take over tasks of the assistant. But if the assistant is left out, the flexibility decreases; small problems, now easily solved by the scrub technician, can become large and time consuming. Also, it will become harder to leam the procedure for inexperienced scrub technicians and assistants. Therefore, reducing the number of team members is not advisable yet for elbow and shoulder replacements. For more standard procedure, like hip and knee

-123-replacements, it may be possible to reduce the number of team members, but more research is needed to confirm this.

In summary, we developed a method to evaluate the per-operative surgical procedure. This method can be used to analyse the shortcomings of procedures. The main shortcomings of both elbow and shoulder joint replacements are repeated actions and waiting. The large variation between procedures showed that elbow and shoulder joint replacements are not standardised procedures. In the future, this method can be used to investigate whether new instruments have improved the per-operative process.

Reference List

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Dunbar,M.J. and Gross,M. (1995). Critical steps in total knee arthroplasty; a method of analysing operative procedures. Int Orthop (19) 265-268.

Joice.P., Hanna,G.B., and Cuschieri,A. (1998). Errors enacted during endoscopic surgery—a human reliability analysis. Appl.Ergon. (29) 6: 409-414.

Minekus,J.P.J., Rozing,P.M., Valstar,E., and Dankelman,J. (2002). Evaluation of humeral head replacements using time-action analysis. J Shoulder Elbow Surg (accepted).

Rasmussen.J. (1983). Skills, rules, and knowledge; signals, signs and symbols, and other distinctions in human performance models. IEEE transactions on systems, man, and cybergenetics. (13) 3: 257-266. Sjoerdsma,W., Meijer,D.W., Jansen,A., den Boer,K.T., and Grimbergen,C.A. (2000). Comparison of efficiencies of three techniques for colon surgery. J Laparoendosc.Adv.Surg.Tech.A (10) 1: 47-53.