Transient quadriceps paresis following local inguinal block for postoperative pain control

Transient Quadriceps Paresis Following Local Inguinal Block for Postoperative Pain Control By Aviel Roy-Shapira, Raymond A. Amoury, Keith W. Ashcraft, Thomas M. Holder, and Ronald J. Sharp Kansas City, Missouri 9 Two patients were observed who had transient quadriceps paresis following local inguinal block for postoperative pain control following inguinal herniorrhaphy. 9 1985 b y Grune & S t r a t t o n . Inc.

INDEX WORDS: Inguinal herniorrhaphy; local anesthesia.

H E USE OF A L O C A L nerve block for postoperative analgesia has become increasingly popular in recent years. 1-3 This is especially advantageous in the pediatric age group where many operations are performed on an ambulatory surgery basis. We have calculated the maximum allowable dose of 0.5% bupivacaine hydrochloride (5 m g / m L Marcaine; Winthrop, Breon Laboratories, NY) to be 0.5 m L / k g and have achieved consistently satisfactory analgesia with smaller doses. Although this is a relatively safe procedure, we have recently encountered an unusual complication associated with infiltration for pain control after inguinal herniorrhaphy in two children.

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CASE REPORTS

Case 1 A 9 year old, 35 kg male, underwent a left inguinal hernia repair. Prior to the closure of the aponeurosis of the external oblique, 11 m L of bupivacaine were infiltrated in the tissues around the internal inguinal ring, between the oblique muscles, and into the inguinal canal. This was followed by routine closure. Two hours later, when the patient wa s fully recovered from general anesthesia, he could not stand on his left leg. Examination revealed an isolated weakness of the left quadriceps femoris muscle. The patient was unable to extend his knee against resistance and had a diminished knee jerk. He complained of no pain, and had anesthesia of the inguinal region. The patient remained under observation for four more hours during which time his weakness gradually disappeared. When the patient was seen a week later, there was no evidence of any residual motor weakness or sensory loss.

From the Department of Surgery, the Children's Mercy Hospital and the University of Missouri, Kansas City School of Medicine, Kansas City. Address reprint requests to Raymond A. Amoury, MD, Surgeonin-Chief, the Children's Mercy Hospital 24th and Gillham Rd, Kansas City~ MO 64108. 9 1985 by Grune & Stratton, Inc. 0022-3468/85/2005~022$03.00/0

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Case 2 A 4 year old, 17 kg male, underwent a right inguinal hernia repair and a negative exploration of the left groin. Again, prior to the closure of the external oblique aponeurosis, 3 m L of bupivacaine was used on each side to infiltrate the internal ring and the inguinal canal. Postoperatively, this patient developed transient weakness of the quadriceps on both sides. As in the first case, this weakness disappeared spontaneously within a few hours and he was dismissed. The patient was seen a week later with complete return of function. In neither case was the site of injection directly over the femoral canals.

DISCUSSION

In order to achieve effective control of pain following an inguinal herniorrhaphy, it is necessary to block three nerves: the iliohypogastric, the ilioinguinal, and the genitofemoral. 4 With the inguinal canal open, infiltration between the external and the internal oblique muscle will block the iliohypogastric; injection of the internal ring will block the genitofemoral nerve; and infiltrating the inguinal canal will anesthetize the ilioinguinal nerve. With the exception of the genital branch of the genitofemoral nerve (that innervates the cremaster muscle) these nerves carry only sensory and autonomic fibers, and so blocking them should cause no motor deficit. The femoral nerve, which supplies the quadriceps, appears to be outside the blocked field. It runs between the psoas and the iliac muscles and passes into the thigh in the muscular lacuna which is separated from the vascular lacuna by the iliopectinate arch. Therefore, in view of this, one would not expect to block this nerve by injecting a local anesthetic in the inguinal canal, even if the technical error of piercing the transversalis layer has been committed. Nevertheless, the two patients presented developed an effective femoral nerve block following the injection of bupivacaine in the operative site. One-half of the maximum allowable dosage was given in each patient and we can only assume that in children the drug can diffuse readily into the perioperative field. Regardless of the cause, the postoperative development of quadriceps femoris paresis can be very alarming. It is important to realize that this could very well be due to the infiltration of the local anesthetic, and that only observation is necessary.

Journal of Pediatric Surgery, Vol 20, No 5 (October), 1985: pp 5 5 4 - 5 5 5

OUADRICEPS PARESIS FOLLOWING INGUINAL BLOCK

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REFERENCES

1. Edmonds-Seal J, Paterson GMC, Loach AB: Local nerve blocks for postoperative analgesia. JR Soc Med 35:1080-1083, 1980 2. Wood G J, Lloyd JW, Bullingham, RES, et al: Postoperative analgesia for day-case herniorrhaphy patients. Anesthesia 36:603610, 1981

3. GouldingFJ:Penileblockforpostoperativepainreliefinpenile surgery. JUrol 126:337, 1981 4. Von Bahr V: Local anesthesia for inguinal herniorrhaphy, in Erikson E (ed): Illustrated Handbook in Local Anesthesia. Philadelphia, Saunders, 1980, pp 52-54