To the Editor:—

We read with great interest the article of Standl et al.  1and would like to congratulate the authors for their well-conducted study. In part 1 of their investigation, they evaluated the effects of a single bolus of sufentanil, bupivacaine, or a combination of both administered through a spinal microcatheter on postoperative pain relief in patients after major orthopedic lower-limb surgery (n = 80). In part 2, they studied the effects of repetitive (maximum of four) subarachnoidal sufentanil injections in a similar but much smaller group of patients (n = 10). We agree that the authors demonstrated that intrathecal sufentanil injections resulted in effective postoperative pain relief. However, we believe that risks and disadvantages associated with this technique outweigh the potential benefits.

Patients undergoing major orthopedic procedures of their lower limb, such as total knee or total hip replacement, deserve appropriate pain management not only during the immediate postoperative period but also for several days. With their technique, Standl et al.  1provided analgesia only for the first 6–7 h after surgery in part 1 of their study and approximately 16 h in part 2. Unfortunately, pain after major lower-extremity joint replacement can be well-controlled while the patient is resting but is exacerbated when mobilization, using for example continuous passive motion, starts on the first postoperative day. Capdevilla et al.  2demonstrated efficacy and safety of continuous infusion of local anesthetics via  femoral catheters for pain management in patients after total knee replacement not only for the immediate postoperative period but also for the subsequent days of mobilization. Singelyn and Gouverneur 3showed that the same technique offers appropriate analgesia after total hip replacements and is associated with minimal side effects.

The authors state that repetitive subarachnoidal sufentanil injections (part 2 of the study) seem not to increase the risk of early respiratory depression. It is doubtful whether a study of only 10 patients justifies such a statement. However, 3 of 10 patients did show signs of respiratory depression after they received the first dose of intrathecal sufentanil. The concerns of the authors are best expressed by the fact that all 10 patients in part 2 of their investigation were admitted to the intensive care unit. Because no other explanation was offered, we conclude that this was done to monitor possible side effects related to the subarachnoidal sufentanil injections. We believe that the need for increased surveillance in these patients represents a major disadvantage. An important attribute of effective postoperative pain management should be safety for the patient and not an increased risk with the need for continuous monitoring.

In conclusion, we believe that the value of subarachnoidal sufentanil administered as repetitive injections via  spinal microcatheters for postoperative pain management in patients after major orthopedic surgery to their lower extremity remains questionable. Epidural anesthesia has been the treatment of choice in these settings. However, since the introduction of low-molecular-weight heparin, epidural hematoma as a complication of this technique has been reported frequently. 4Other methods of perioperative pain management, such as continuous infusion of local anesthetics via  psoas, 5sciatic, 6or femoral catheters, have been shown to be safe, to provide excellent pain relief, and to improve outcome of patients undergoing major surgery of the lower extremities. 2,3,7These methods have become the gold standard and should be used as a measurement when new techniques are evaluated.

Standl TG, Horn EP, Luckmann M, Burmeister MA, Wilhelm S, Schulte am Esch J: Subarachnoid sufentanil for early postoperative pain management in orthopedic patients: A placebo-controlled, double-blind study using spinal microcatheters. A nesthesiology 2001; 94: 230–8
Capdevilla X, Barthelet Y, Biboulet P, Ryckwaert Y, Rubenovitch J, d’Athis F: Effects of perioperative analgesic technique on the surgical outcome and duration of rehabilitation after major knee surgery. A nesthesiology 1999; 91: 8–15
Singelyn FJ, Gouverneur JM: Postoperative analgesia after total hip arthroplasty: i.v. PCA with morphine, patient-controlled epidural analgesia, or continuous “3-in-1” block? A prospective evaluation by our acute pain service in more 1,300 patients. J Clin Anesth 1999; 11: 550–4
Lumpkin MM: FDA public health advisory. A nesthesiology 1998; 88: 27A–8A
Bruce BD, Lee E, Croitoru M: Psoas block for surgical repair of hip fractures: A case report and description of a catheter technique. Anesth Analg 1990; 71: 298–301
Smith BE, Fischer ABJ, Scott PU: Continuous sciatic nerve block. Anesthesia 1984; 39: 155–7
Chelly JE, Greger J, Gebhard R, Khan A: Effects of continuous femoral infusion on outcome in patients undergoing total knee replacement (abstract).