Lumbar Plexus Block as an Effective Alternative to Subarachnoid Block for Intertrochanteric Hip Fracture Surgeries in the Elderly.

BACKGROUND AND AIMS: Elderly patients with hip fractures pose a medical challenge for the anesthesiologist and are often associated with a high incidence of perioperative morbidity and mortality. We aimed to compare the efficacy of lumbar plexus block (LPB) with subarachnoid block (SAB) in elderly patients undergoing closed reduction and internal fixation for hip fractures.
METHODS: In this observational study, 50 patients with femoral intertrochanteric fracture were divided into LPB group and SAB group of 25 each by convenient sampling. Patients in the LPB group were given 20-25 ml of 0.5% bupivacaine to block the ipsilateral lumbar plexus with nerve stimulator assistance, whereas the patients in the SAB group received 0.5% bupivacaine intrathecally. Student's t-test was used for comparing the time for performing block, the time to achieving block, the time to the first request for analgesia, and the hemodynamic variables.
RESULTS: Lumbar plexus blockade took a longer time for performing and achieving block (P < 0.001). The time for the first request for analgesia was significantly longer in the LPB group (P < 0.001). A statistically significant reduction in blood pressures was noted in the SAB group.
CONCLUSIONS: Lumbar plexus blockade offered more stable intraoperative hemodynamics and longer duration of postoperative analgesia in elderly patients undergoing hip fracture surgery.

INTRODUCTION

Elderly patients with hip fractures pose a medical challenge for the anesthesiologist and are often associated with a high incidence of perioperative morbidity and mortality. Due to increasing age of the general population as a result of better health-care facilities, it seems reasonable that we encounter more cases of hip fractures now than in the previous decades.[1] The majority of these fractures occur in the elderly population who have various comorbidities attributable to the normal process of aging.[23] Surgical repair is the method of choice to treat such fractures. As a result, surgery for hip fracture represents one of the most common emergency orthopedic procedures performed.[456]

Regional anesthesia is usually the mode of anesthesia for hip fracture surgeries, and various regional anesthetic techniques have been described to achieve surgical anesthesia of the hip, which requires blockade of the femoral, obturator, and the lateral cutaneous nerve of the thigh.[7] Subarachnoid block (SAB) and peripheral nerve blockade are the two techniques commonly employed. The postoperative outcome in these elderly patients undergoing surgical repair for proximal femoral fractures and the type of anesthesia administered have still not been determined with certainty.

SAB has some inevitable consequences such as innate hemodynamic changes and unpredictable level of block.[8] Peripheral nerve blockade in the form of lumbar plexus block (LPB) has also been employed for surgical anesthesia for the hip; however, it has not been used routinely, mainly due to a lack of expertise and unidentified complications.[910] LPB could be safe because of the targeted somatic nerve block in the psoas region, which prevents dispensable sympathetic block even in cardiovascular-compromised patients.[1112] The prevention of intraoperative cardiovascular complications might be a critical factor in reducing postoperative morbidity.

The study was designed to compare the efficacy of LPB with SAB in elderly patients undergoing closed reduction and internal fixation for hip fractures. The parameters measured for assessing the efficacy of the mode of regional anesthesia employed were the time for performing block, the time to achieving block, operation time, and the time to the first request for analgesia.

METHODS

The study was started after obtaining approval from the Institutional Ethics Committee (IEC/MES/17/2017 dt 18/03/2017). Written informed consent was obtained from the patients to participate in the study. The study design was observational.

A previous study by Amiri et al. compared LPB and combined femoral nerve block and spinal anesthesia in patients with femoral intertrochanteric fracture.[13] Assuming 30% difference and at two-sided Type 1 error of 0.05 and power of 90%, a sample size of 25 per group was obtained. Fifty patients taken up for closed reduction and internal fixation for intertrochanteric fractures participated in the study, of which 25 patients underwent the procedure under LPB and other 25 under SAB by convenient sampling. All of them belonged to Physical Status Classes I, II, or III as outlined by the American Society of Anesthesiologists. Patients <18 years of age and patients with injection site infection, coagulopathies, multiple fractures, and psychological disorders affecting patient cooperation were excluded from the study. Patients who participated in the study underwent elective surgery at the department of anesthesiology in a tertiary referral hospital during the period from January 2016 to March 2017.

Preoperative assessment was performed by a senior resident in anesthesiology, which included a detailed history, general physical examination, and systemic examination. Basic investigations were done, which included complete blood count, blood grouping with Rh typing, random blood sugar, serum urea and creatinine, serum electrolytes, electrocardiography (ECG), chest X-ray, and an echocardiogram if indicated. Nil per oral orders were as per the standard protocol. Anesthetic procedure (LPB or SAB) was performed in patients as per the decision taken by attending consultant anesthesiologist.

Routine monitoring included ECG, pulse oximetry (SpO2), and noninvasive blood pressure. An intravenous line was secured using an 18-G cannula on the right or left forearm of all the patients to supplement intravenous fluids and drugs. All patients were given intravenous midazolam 0.025 mg/kg as premedication. Supplemental oxygen was provided using simple face mask at the rate of 6 L/mt. Five minutes after premedication and before positioning for regional block, the baseline values of heart rate and blood pressures were recorded.

In the SAB group, the patient was positioned in the lateral position (nonaffected side up) with maximal possible flexion at the hip and the knees or sitting position whichever was comfortable for the patient. After skin preparation with antiseptic solution and sterile draping, SAB was performed by either a midline or paramedian approach at the second and third or third and fourth lumbar interspinous space with 25-G Quincke needle. On confirming free backflow of clear cerebrospinal fluid, 1.5–2 ml of hyperbaric bupivacaine 0.5% was given, the needle was removed, and the patient was turned supine.

Patients assigned in the LPB group were administered a single-shot LPB. The patients were placed in the lateral (Sims) position with the side to be blocked uppermost. The foot on the side to be blocked was positioned over the dependent leg, so that twitches of the quadriceps muscle and patella could be seen easily. The hip on the side to be blocked was flexed to 30° and the ipsilateral knee was flexed to 90°. The skin was prepared with antiseptic solution. The site of needle insertion was determined as follows. The intercristal line was drawn connecting the iliac crests. The spinous processes (SPs) were marked, and posterior superior iliac spine (PSIS) was identified. A line through the PSIS was drawn parallel to the line joining the SP. The site of needle insertion was the junction of the lateral third and medial two-thirds of a line between the SP and the PSIS and 1 cm cephalad to the intercristal line usually at the level of L4 vertebra. A 21-G, 100-mm long Stimuplex® A insulated sterile needle was connected to the Stimuplex® HNS 12. Nerve stimulator to deliver a current of 1.5 mA (1.5 mA, 2 Hz, 0.1–0.3 ms) was inserted perpendicular to all planes. Palpation of the anterior thigh was a useful way to make sure that the motor response was indeed that of the quadriceps muscles. With needle advancement to a depth of a few centimeters, local twitches of the paravertebral muscles were obtained first. The needle was then advanced further, until twitches of the quadriceps muscle could be elicited or bony contact with the transverse process of the L4 vertebra was made. If the bone was encountered, the needle was withdrawn and directed caudad under the transverse process and advanced no further than 15–20 mm, until twitches of the quadriceps muscles were elicited. After these twitches were observed, the current was lowered to produce stimulation between 0.5 and 1.0 mA. The absence of motor response was confirmed at current <0.5 mA, which could indicate needle placement in the dural sleeve. At this point, after negative aspiration, 20–25 mL of 0.5% bupivacaine was injected slowly and with frequent aspirations to rule out inadvertent intravascular needle placement. The patient was then turned back to a supine position after performing the block.

Efficacy of the mode of regional anesthesia employed was assessed by the following parameters: (a) the time for performing block (from beginning of drape and withdrawal of the needle), (b) the time to achieving block (from withdrawal of the needle to reduction of patient's pain), (c) operation time, and (d) the time to the first request for analgesia. Hemodynamic monitoring was done at 0, 5, 10, and 15 min after performing the procedure. Up to 20% of variation from the baseline of these parameters was considered as the normal range.

Side effects such as nausea, vomiting, pruritus, drowsiness, and respiratory depression were noted after the drug administration and in the recovery period.

Data were analyzed using Microsoft Excel and Epi info (Epi Info 7 Version 7.2.0.1, Centers for Disease Control and Prevention (CDC), Department of Health and Human Services, Atlanta, Georgia, US). Parametric variables were described as mean ± standard deviation, and qualitative variables were described as number (percentage) and as median and range. Continuous variables were analyzed by the Student's t-test. Categorical variables were analyzed by the Chi-square test or Fisher's exact test, and the data were compared between the two groups. The significance level was set at P < 0.05.

RESULTS

The age and gender of all the patients were noted. There was no significant difference between the two groups with respect to age and sex [Table 1]. Intertrochanteric fracture femur was observed to be common in elderly females in both the groups. Table 2 shows the comparison of anesthesia parameters assessing the efficacy of the mode of regional anesthesia employed. The time for performing the block was significantly longer in the LPB (P < 0.001) group. The time to achieving the block was also significantly longer in the LPB (P < 0.001) group. Furthermore, the operation time was longer in the LPB (P < 0.015) group, but the time to the first request for analgesia was earlier in the SAB (P < 0.001) group. The hemodynamic parameters were compared. There was a significant reduction in systolic [Table 3] and diastolic blood pressures [Table 4] in the SAB group. Main anesthesia-related complications such as nausea, vomiting, pruritus, drowsiness, and respiratory depression were documented in the postoperative period [Table 5]. The occurrence of nausea was significantly higher in the SAB group, whereas there were no complications observed in the LPB group.

Table 1

Demographic data

Parameters	SAB group (n=25)	LPB group (n=25)	P
Age (years), mean±SD	73.08±9.802	68.60±8.480	0.090
Sex (male/female)	11/14	11/14

Student’s t-test. SD=Standard deviation, SAB=Subarachnoid block, LPB=Lumbar plexus block

Table 2

Comparison of anesthesia parameters assessing the efficacy

Anesthesia parameters assessing efficacy	SAB group (n=25)	LPB group (n=25)	P
Time for performing block (min), mean±SD	7.68±1.701	20.72±3.985	0.000
Time for achieving block (min), mean±SD	3.44±0.917	9.44±2.219	0.000
Operation time (min), mean±SD	58.52±10.493	66.84±12.792	0.015
Time to the first request for analgesia (h), mean±SD	3.796±0.728	8.702±1.260	0.000

Student’s t-test. SD=Standard deviation, SAB=Subarachnoid block, LPB=Lumbar plexus block

Table 3

Comparison of changes in systolic blood pressure (mmHg)

Systolic blood pressure (mmHg)	SAB group (n=25)	LPB group (n=25)	P
Before block, mean±SD	154.28±10.526	147.28±21.596	0.154
0 min after block, mean±SD	151.76±9.593	150.04±13.498	0.606
5 min after block, mean±SD	135.36±8.717	149.72±12.801	0.000
10 min after block, mean±SD	128.08±9.363	148.24±12.726	0.000
15 min after block, mean±SD	121.76±11.148	147.08±12.446	0.000

Student’s t-test. SD=Standard deviation, SAB=Subarachnoid block, LPB=Lumbar plexus block

Table 4

Comparison of changes in diastolic blood pressure (mmHg)

Diastolic blood pressure (mmHg)	SAB group (n=25)	LPB group (n=25)	P
Before block, mean±SD	88.96±6.079	90.08±13.503	0.708
0 min after block, mean±SD	85.24±6.654	85.76±7.688	0.799
5 min after block, mean±SD	78.08±6.800	85.88±7.452	0.000
10 min after block, mean±SD	74.80±5.895	85.08±6.204	0.000
15 min after block, mean±SD	73.12±5.890	84.64±6.123	0.000

Student’s t-test. SD=Standard deviation, SAB=Subarachnoid block, LPB=Lumbar plexus block

Table 5

Complications

Parameters	SAB group (n=25)	LPB group (n=25)	P
Nausea	3	0	0.235
Vomiting	0	0
Pruritus	0	0
Drowsiness	0	0
Respiratory depression	0	0

Fisher exact test. SAB=Subarachnoid block, LPB=Lumbar plexus block

DISCUSSION

During surgery, sufficient muscle paralysis is of great importance in the reduction of fractures.[14] A loss of muscular tonicity is sufficient in the less muscular elderly patients for good operative condition. The surgeon satisfaction rating for intertrochanteric surgery was 8.9 ± 1 for LPB in comparison with 8.7 ± 1.2 for combined SAB and femoral block in a study which included 32 patients with intertrochanteric fractures.[13] In another study of 50 patients where LPB was used in the management of hip surgeries, the surgeon satisfaction score was 9.8 ± 1.[14] Muscle relaxation was comparable between the two groups in these studies. In the present study, surgeon satisfaction was assessed by the intraoperative time taken for the procedure. It was significantly longer in the LPB group, which suggests that muscle relaxation was not as adequate when compared to the SAB group.

A single-shot LPB provided satisfactory intraoperative conditions and considerable postoperative pain control when compared with combined femoral block plus spinal anesthesia for perioperative management of hip fractures in a study by Amiri et al.[13] The duration of analgesia with peripheral nerve blocks was longer than spinal anesthesia. In the present study also, the time to the first request for analgesia was significantly longer in the LPB group than in the SAB group, showing a longer postoperative pain-free period in the patients given LPB. If spinal anesthesia is scheduled, providing a femoral nerve block before SAB produced better postoperative analgesia.

Local anesthetic nerve blockade is an invaluable adjunct to systemic analgesia in geriatric patients with hip fractures, leading to decreased opioid side effects and improved long-term outcome. Marino et al. reported that femoral blocks and continuous LPB significantly reduced the need for opioids.[15]

As seen in the study by Amiri et al., LPB, which was considered as a primary option for hip fracture surgeries, was less time-consuming and required only one skin puncture site.[14] However, the proficiency and expertise required in LPB may matter. This conclusion was reflected in our study. The time taken for performing LPB in our study was significantly longer. The actual time required for performing LPB could be much lesser if the provider is experienced and familiar with such nerve blocks. This could be the probable reason for the longer time duration required for performing block in the LPB group in our study.

Regardless of anesthetic technique, intraoperative blood pressure stability is a major concern in elderly people. The fall in blood pressure can prove to be detrimental in them and contributes to higher morbidity and mortality. In a study by Davis et al., it was found that larger decrements of systolic blood pressure occur with spinal and epidural anesthesia.[16] The study also reported that hypotension, defined as a decrease of systolic blood pressure more than 20% of preinduction values for >10 min, occurred in 38% of patients with SAB and 24% of patients under general anesthesia. In the present study, it was found that there was no clinically significant fall in the blood pressure after LPB, whereas 44% of patients undergoing SAB developed a significant fall in blood pressure. This showed that an LPB is a good alternative to SAB or general anesthesia for hip fracture surgeries. This was in agreement with Amiri et al. who found that LPB provided excellent hemodynamic stability as evidenced by the absence of abrupt and intense variation in heart rate, systolic and diastolic blood pressures, and mean arterial pressure after LPB.[14] According to Ho et al. and Asao et al., LPB was suggested as the first choice in the elderly with a severe hemodynamic compromise such as severe aortic stenosis and also in critically ill patients with severe heart failure due to the excellent intraoperative hemodynamic stability provided.[17]

In a study by Rokhtabnak et al., a targeted peripheral nerve block helped maintain a smooth intraoperative course in a patient with lower-limb fracture complicated with severe aortic stenosis.[18] There are other various studies which emphasize the merits of targeted lower limb nerve blocks against central neuraxial blocks, i.e., spinal anesthesia for lower limb surgeries in severely cardiovascular-compromised patients.

A meta-analysis regarding anesthesia for major orthopedic surgical procedures of the hip reported that blocking of peripheral nerves in the lower extremity resulted in fewer side effects such as hypotension, urinary retention, nausea, and itch.[19] In the present study, no complication was noted in the patients who were given LPB, whereas three patients had nausea in the SAB group.

Although various studies have been performed comparing different modes of regional anesthesia for hip fracture surgeries in the elderly, most of these have been performed outside our country, and hence, there is a paucity of data. The strength of this study is that it represents one of the few published reports from India comparing the two modes of regional anesthesia in elderly patients.

As a limitation in our study, the sample size was not large and the expertise in LPB was less. Nevertheless, considering the advantage of very minimal or insignificant changes in the intraoperative hemodynamics in this highly vulnerable group of patients, LPB serves as a good alternative to SAB and can be safely recommended as an anesthetic technique offering adequate postoperative analgesia.

CONCLUSIONS

With expertise and familiarity, LPB is an effective alternative to SAB as an anesthetic technique for intertrochanteric hip fracture reduction surgeries. Lumbar plexus blockade offers a more stable intraoperative hemodynamics and provides longer duration of analgesia postoperatively in patients undergoing surgery for intertrochanteric fracture femur, thus providing a platform for a stable postoperative course.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.