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Table of Contents  
Year : 2022  |  Volume : 16  |  Issue : 1  |  Page : 36-41  

A clinical comparison between single-space technique and double-space technique for combined spinal and epidural anesthesia

1 Department of Anaesthesia, Vydehi Institute of Medical Sciences and Research Centre, Bengaluru, Karnataka, India
2 Department of Anaesthesia, East Point College of Medical Sciences, Bengaluru, Karnataka, India
3 Department of Anaesthesia, Rajendra Institute of Medical Sciences, Ranchi, Jharkhand, India
4 Department of Anaesthesia, MVJ Medical College and Research Hospital, Bengaluru, Karnataka, India
5 Department of Critical Care Medicine, Rajendra Institute of Medical Sciences, Ranchi, Jharkhand, India

Date of Submission27-Jan-2022
Date of Decision12-Apr-2022
Date of Acceptance22-Apr-2022
Date of Web Publication31-May-2022

Correspondence Address:
Dr. Shailesh Kumar
Department of Anaesthesia, MVJ Medical College and Research Hospital, Bengaluru - 562 114, Karnataka
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/aer.aer_19_22

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Background: Combined spinal and epidural anesthesia (CSEA) is commonly performed by double space technique (DST) and single space segment technique (SST) or needle-through-needle technique (NNT). Aims and Objectives: We designed a double-blind randomized controlled study to compare the effect of the double-space technique with that of the single-space technique on time required by the procedure, the number of attempts, and a level of sensory, side effects and cost-effectiveness. Materials and Methods: Patients undergoing elective lower abdominal and lower limb surgeries under regional anesthesia were randomized to receive CSEA with either the double-space technique (double group, n = 30) or the single-space technique (single group, n = 30). In the single group, the procedure was performed at the L3-4 interspace using the needle-through-needle technique. In the double group, an epidural catheter was inserted at the L1–2 interspace, and dural puncture was performed at the L3–4 interspace. Results: The single space (needle-through-needle) technique for CSE takes less time, less number of spinal punctures. There was no difference between the two groups in terms of side effects. Sensory level at T10 on 5 min in group I was 90% and group II was 100% whereas at T8 it was 10% in group I; sensory level at T10, T8 and T6 on 10 min. in group I were 53.3%, 43.3% and 3.3% respectively whereas in group II were 80%, 16.7% and 3.3% respectively; sensory level at T10, T8, T6 and T4 on 15 min. in group I were 6.7%, 43.3%, 50% and 0% respectively whereas in group II were 23.3%, 50%, 23.3% and 3.3% respectively; and sensory level at T4, T6 and T8 on 20 min. in group I were 0%, 73.3% and 26.7% respectively whereas in group II were 16.7%, 33.3% and 50% respectively. Conclusions: Single-space (needle-through-needle) CSEA takes less time, less number of spinal punctures and results in improved patient satisfaction. There were no differences in intraoperative variables between the DST and SST for CSEA.

Keywords: Combined spinal and epidural anesthesia, double-space technique, single-space technique

How to cite this article:
Basheer P, Brijesh G C, Kumar R, Kumar S, Kumar P, Prakash J. A clinical comparison between single-space technique and double-space technique for combined spinal and epidural anesthesia. Anesth Essays Res 2022;16:36-41

How to cite this URL:
Basheer P, Brijesh G C, Kumar R, Kumar S, Kumar P, Prakash J. A clinical comparison between single-space technique and double-space technique for combined spinal and epidural anesthesia. Anesth Essays Res [serial online] 2022 [cited 2022 Sep 24];16:36-41. Available from:

   Introduction Top

The combined spinal-epidural technique (CSE) has become increasingly popular in recent years. The combined spinal-epidural was first described by Soresi[1] in 1937 and was first performed by Curelaru[2] in 1979. CSE allows a rapid onset of the neuraxial blockade, which can subsequently be prolonged or modified. Spinal anesthesia provides fast and reliable segmental anesthesia with minimal risk of toxicity whereas epidural anesthesia provides perioperative anesthesia alone or in combination with general anesthesia, followed by excellent analgesia in the postoperative period.[3],[4] CSE is widely used in orthopedic, urologic, and gynecologic surgery. Major CSE benefits are the need for low doses of medications, low incidence of motor blockade, adequate sensory block, the ability to extend the area of blockade if the surgical fields need to be extended, and excellent analgesia.[5] However, the use of CSE anesthesia or analgesia also introduces the potential for complications, such as technical failure, migration of epidural catheter[6] in subarachnoid space which leads to extensive block,[7],[8] drug entering into subarachnoid space through the migrated epidural catheter may cause delayed respiratory depression, meningitis,[9] inadvertent dural puncture with the wide bore Tuohy needle,[10],[11] knotting of catheters.[6]

Several CSE techniques are described,[3] and several technical improvements have been proposed as attempts to improve the techniques and reduce the incidence of complications. Combined spinal and epidural anesthesia (CSEA) is commonly performed by double-space technique (DST) and single-space segment technique (SST) or needle-through-needle technique (NNT). Both CSEA techniques have advantages and disadvantages. The advantage of the single-space technique is less discomfort, less trauma, and a decrease in the morbidity associated with the DST such as backache, epidural vein puncture, inadvertent dural puncture, hematoma, and infections. However, single-space technique can itself result in accidental dural puncture and postspinal headache.

The single-space “needle-through-needle” technique is the most widely used CSE technique in the literature.[12] Some reports state that the success rate of the procedure is higher for DST than NTN,[11],[12],[13] and the epidural kit and spinal needle used for DST are cheaper than those required for NTN. Moreover, NTN has several potential problems related to performing spinal block before epidural catheter insertion.[3],[14] On the other hand, DST requires more time to perform than NTN and the two separate skin infiltrations can cause more patient discomfort and back pain.[11],[15],[16]

We designed the present study to compare single-space and DSTs for CSEA in terms of time required by the procedure, the number of attempts, and a level of sensory and motor block, postoperative complications, and patient comfort and cost-effectiveness.

   Materials and Methods Top

After taking approval from Institutional Ethics Committee (VIEC/2015/APP/099), this cross-sectional, prospective, randomized, double-blind study was conducted during the period of January 2016 to January 2017. The study conformed to the Helsinki Declaration (World Medical Association, 1995), and the applicable guidelines for Good Clinical Practices were looked into consideration. All study components were examined in accordance with the “CONSORT guidelines” for improving the reporting of randomized clinical trials.” Informed and written consent was taken from all the patients before enrollment in the study and the use of patient data for research and educational purposes. The study involved elective lower abdominal and lower limb surgeries under regional anesthesia in sixty patients of the American Society of Anesthesiologists (ASA) physical status Class I or II patients of either gender in the age group 18–60 years. Patients refusal for regional anesthesia, ASA PS classes ≥II, pregnant and lactating women, any contraindication to spinal or epidural anesthesia, uncooperative patients, hypotension, previous spinal surgeries, spine abnormalities, local site infection and coagulation abnormalities, poorly controlled hypertension, angina, cardiopulmonary disease, hematological disease, neurologic, psychiatric disease were excluded from the study. Each patient fulfilling the eligibility criteria was randomly allocated to two different groups (Group S, n = 30 and Group D, n = 30) and given a computer-generated code in a random way so that each patient is assigned to a group by chance, not by choice. The codes were kept in sealed envelopes by a person not involved in the study. Preanesthetic evaluation was done a day before surgery. The procedure of epidural anesthesia was explained to the patients. The procedure of block and possible complications were explained to the patients as well. Preparation included an overnight fast of 8 h before the surgery. All patients have given oral alprazolam 02.5 mg and ranitidine 150 mg on the night before the surgery.

On arrival at the operating room, an intravenous (i.v.) line was secured using an 18G cannula and the patient was preloaded with 10–15−1 lactated Ringer's solution. Standard monitors were attached; baseline electrocardiogram, noninvasive blood pressure, heart rate (HR), respiratory rate, and pulse oximetry (SpO2) were noted. All patients were made aware of their pain measurement by Visual Analogue Scale (VAS). Patients were positioned in left lateral position; ultrasound (ACUSON Freestyle™, Siemens Healthcare, Camberley, UK) scanning was performed before the procedure in a nonsterile manner by using a 2–5 MHz curved probe. With all aseptic precautions, a skin wheal was raised in L3–L4 interspaces with 2 ml of 2% Lignocaine.

In Group S (SST, n = 30), an 18G Tuohy needle (ESPOCAN; B. BRAUN) was advanced into L3–L4 interspace using the loss of resistance (LOR) technique to air. Then, epidural space was identified. A 27 gauge (G) spinal needle was advanced through an epidural needle to perform subarachnoid block (SAB) after confirming free flow of cerebrospinal fluid (CSF), and 3 mL of 0.5% hyperbaric bupivacaine was injected in the subarachnoid space. The spinal needle was withdrawn, and the epidural catheter was introduced into the epidural space and was fixed at required depth. A test dose of 3 mL lignocaine combined with epinephrine was injected after negative aspiration for all patients, and sensory and motor blocks were assessed before the surgical procedure starts.

In Group D (DST, n = 30), using an 18G Tuohy needle (Perifix; B. Braun), epidural space at the L1–L2 interspace was identified with LOR to air. Then, an epidural catheter was introduced and fixed, and 3 mL of 2% lignocaine combined with epinephrine was administered through the epidural catheter as a test dose. Then, using a 27 G spinal needle, lumbar puncture at L3–L4 space was done. After confirming free flow CSF, 3 mL of 0.5% hyperbaric bupivacaine was injected. Sensory and motor block were assessed before the surgical procedure starts.

All the patients were monitored for cardiorespiratory problems, and side effects if any, and were given supplemental oxygen. General anesthesia was planned in case of failed or inadequate block. Fluid management was done according to requirements including the fluid deficit, maintenance, and blood loss. Intraoperatively and postoperatively vital signs were recorded. The intensity and duration of pain were measured using a Visual Analog Scale (VAS) every 30 min for the 1st h and hourly thereafter, and the duration of sensory analgesia was noted and recorded from the time; the epidural drug was administered to the time the patient complained of pain during postoperative follow-up. Patients were asked to point out the intensity of their pain on VAS.[17] Patients who complained of pain more than 5 cm on the VAS were noted. That point was taken as the endpoint of fair analgesia and was managed by top-up doses of 8 mL of 0.125% bupivacaine. Time of first rescue analgesic required and VAS score at that time was noted.

HR, systolic blood pressure, diastolic blood pressure and mean blood pressure were measured every 1 min for the first 5 min and every 5 min thereafter till the end of surgery. The onset of SAB was recorded using a loss of a pinprick sensation at the site of surgery to start with at least T10 level for orthopedic surgeries, T8 for lower abdominal surgeries and T6 level for upper abdominal surgeries. The maximum level achieved is checked by pinprick every 5 min, and the time taken for the same is noted from the time of SAB. First epidural top-ups are given after 1 h of onset of SAB, and subsequent top-ups are given to maintain the maximum level of blockade which was achieved by the low dose spinal to facilitate the surgery. Level of sensory analgesia was defined as loss of sensation to pinprick done with the help of hypodermic needle at every 10 min interval till the level regress two segments below the maximum level and time taken is noted. Side effects such as hypotension, bradycardia, dizziness, nausea, vomiting, pruritus, shivering, respiratory depression, and urine retention were noted, and corrective therapeutic measures were taken. The sensory level of analgesia was assessed by observing the reaction to a pinprick and the level tabulated. The motor level blockade was observed using a modified Bromage scale, and results were tabulated (score 1: complete block [unable to move feet or knees], score 2: almost complete block [able to move feet only], score 3: partial block [just able to move knees], score 4: detectable weakness of hip flexion while supine [full flexion of knees], score 5: no detectable weakness of hip flexion while supine, and score 6: able to perform partial knee bend). Rescue analgesia is given according to the patient's demand along with timely institutional epidural top-ups such as to maintain the Visual Analog Scale (VAS) Scoring and Faces Pain Scale.[18]

A prospective sample size calculation indicated that 30 patients were required in two groups to have an 80% power to detect a 25% difference at Type I (α) error of 0.05 for the duration of analgesia and assuming a drop out of 10%.

Statistical analysis

The collected data were analyzed with SPSS 23 (IBM, Armonk, New York, USA). For categorical variables, percentage analysis was used, and for continuous variables, the mean and standard deviation were used to explain the data descriptive statistics frequency analysis. To find the significant difference between the bivariate samples in the independent groups, the unpaired sample t-test and the Mann–Whitney U test were used. To find the significance in categorical data, Chi-square test and Fisher's exact test were used. In all the above statistical tools, the probability value of 0.05 was considered a significant level.

   Results Top

A total of sixty patients met the inclusion criteria and were analyzed for this study [Figure 1]. Patients' characteristics such as age, gender, height, weight, ASA PS classification, duration of surgery, and the number of spinal and epidural punctures on the first and second attempts in both groups were comparable [Table 1].
Figure 1: CONSORT flow diagram

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Table 1: Demographic characteristics of patients of both groups

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[Figure 2] shows that the sensory level at T10 at 5 min in Group I was 90% and Group II was 100% whereas at T8, it was 10% in Group I; the sensory level at T10, T8, and T6 on 10 min in Group I were 53.3%, 43.3%, and 3.3%, respectively, whereas in Group II were 80%, 16.7%, and 3.3%, respectively; the sensory level at T10, T8, T6, and T4 on 15 min in Group I were 6.7%, 43.3%, 50%, and 0%, respectively, whereas in Group II were 23.3%, 50%, 23.3%, and 3.3%, respectively; and sensory level at T4, T6, and T8 on 20 min in Group I were 0%, 73.3%, and 26.7%, respectively, whereas in Group II were 16.7%, 33.3%, and 50%, respectively. There were no differences in systolic blood pressure, diastolic blood pressure, and HR (HR except at the 10th, 19th, and 30th min) between the two groups (P > 0.05) [Figure 3], [Figure 4], [Figure 5]. [Table 2] shows the incidence of side effects.
Figure 2: Sensory level in both the groups

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Figure 3: Systolic blood pressure trend in both the groups

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Figure 4: Diastolic blood pressure trend in both the groups

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Figure 5: Heart rate trend in both the groups

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Table 2: Incidence of side effects

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   Discussion Top

The present study was a randomized controlled trial that compared two CSEA methods: single-and double-space techniques following the NNT were performed with a commercially available kit. This randomized, blinded study showed that the single-space (needle-through-needle) technique for CSE takes less time, less number of spinal punctures, and results in improved patient satisfaction. In addition, it is not more difficult to perform and has a similar success rate as the DST.

CSE is a well-known technique and widely used procedure, and both the double- and single-space techniques have merits. However, few quantitative studies have been performed directly comparing these two techniques. Lyons et al. compared needle-through-needle and separate-needle CSE and observed that separate-needle CSE had a lower spinal failure rate (4% vs. 16%) and less hypotension and took no longer than needle-through-needle CSE and the separate-needle group had higher blocks.[13] When compared to previous epidural analgesia, a larger group of people in the separate-needle group did not favor the approach, but this was not statistically significant. This dissatisfaction was ascribed to the fact that separate-needle CSE required two injections while needle-through-needle CSE required only one. The spinal needle is inserted through the epidural needle and beyond its tip until it punctures the dura after the epidural space has been identified. The CSE kit utilized in this study comprises an epidural needle with a small hole in the larger curve of the tip, known as the “back eye,” that allows the spinal needle to go in a straight path.

The duration of the procedure in SST was shorter in comparison to DST which was statistically significant. The necessity for only one puncture site and the higher frequency of patients with normal body anatomy in this group can explain the observed difference. Similarly, an earlier study comparing three different techniques found no difference in the time needed to perform the block.[12] However, one study found greater success with the DST.[16] There were no differences in procedural time between the two groups, and this aspect seems to have little impact on the clinical choice of CSEA technique for anesthesiologists.[19] Casati et al. reported that the NNT requires less time, has no greater failure rate, and results in greater parturient satisfaction than the double-space technique.[11]

The higher number of epidural and spinal punctures observed with the DST can be explained by a technically more challenging thoracic approach. The body habitus, spinal landmarks, and anatomy influenced the number of epidural punctures. It was suggested that excessive paramedian deviation of the epidural needle may affect dural puncture during the needle-through-needle CSE technique. Moreover, the wrong passage of the spinal needle through the Tuohy curve instead of the back hole may contribute to the failure of dural puncture.[20] The reduced number of skin punctures and 3-min shorter duration anesthetic procedure in SST may theoretically decrease the incidence of pain, infection at puncture sites, and formation of hematomas.[21] Better patient acceptance was observed after a single puncture than after DST. An additional skin punctures although often judged as trivial in itself by the anesthesiologist on patient acceptance.

There was no difference between the groups in the incidences of hypotension. There was no significant difference between the groups in the incidences of side effects such as backache, headache, nausea, and dizziness which are known to affect patient satisfaction. However, these side effects are not considered to have caused the difference in satisfaction scores between the groups. We did not observe any complications and were independent of body habitus, spinal landmarks, or anatomy. This result is consistent with the literature, which claims that “severe complications of central neuraxial blocks are rare.”[12],[22]

Because the Tuohy needle works as an introducer, CSE conducted as SST facilitates the use of small spinal needles or pencil-point needles. The frequency of postdural puncture headache is reduced even when Quincke-point needles are used. Compression of the dural sac by the epidural injection is thought to be responsible.[23] Proposed reasons for the low incidence of postdural puncture headache include the use of epidural injections or infusions to minimize CSF leak, the use of spinal opioids, use of appropriately fine pencil-point needles, oblique spinal needle dural puncture due to deflection by the Tuohy needle, and good technique reducing accidental dural punctures. During needle-through-needle CSE, the epidural needle acts as the optimum introducer and may reduce multiple dural punctures.[24],[25] In our study, we found one patient in both groups suffered from postdural puncture headache, statistically not significant. In our study, the total cost incurred for providing anesthesia and analgesia was less in the DST group than SST group. Attributing to the low fixed cost in the DST group and better patient acceptance in the SST group, no studies were found in our search comparing cost-effectiveness between SST and DST combined spinal-epidural anesthesia.

We did not observe enhanced recovery after surgery and epidural tip-positive bacteriological findings. This limits the understanding of the anesthetic technique's effect on recovery. Therefore, additional research is needed to understand the benefits.

   Conclusion Top

Single-space (needle-through-needle) CSEA takes less time, less number of spinal punctures, and results in improved patient satisfaction. There were no differences in intraoperative variables between the DST and SST for CSEA.

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Conflicts of interest

There are no conflicts of interest.

   References Top

Soresi AL. Epidural anesthesia. Anaesth Analg 1937;16:30610.  Back to cited text no. 1
Curelaru I. Long duration subarachnoid anaesthesia with continuous epidural block. Prakt Anaesth 1979;14:71-8.  Back to cited text no. 2
Cook TM. Combined spinal-epidural techniques. Anaesthesia 2000;55:42-64.  Back to cited text no. 3
Rawal N, Holmström B, Crowhurst JA, Van Zundert A. The combined spinal-epidural technique. Anesthesiol Clin North Am 2000;18:267-95.  Back to cited text no. 4
Rawal N, Van Zundert A, Holmström B, Crowhurst JA. Combined spinal-epidural technique. Reg Anesth 1997;22:406-23.  Back to cited text no. 5
Norris MC, Grieco WM, Borkowski M, Leighton BL, Arkoosh VA, Huffnagle HJ, et al. Complications of labor analgesia: Epidural versus combined spinal epidural techniques. Anesth Analg 1994;79:529-37.  Back to cited text no. 6
Holmström B, Rawal N, Axelsson K, Nydahl PA. Risk of catheter migration during combined spinal epidural block: Percutaneous epiduroscopy study. Anesth Analg 1995;80:747-53.  Back to cited text no. 7
Bernards CM, Kopacz DJ, Michel MZ. Effect of needle puncture on morphine and lidocaine flux through the spinal meninges of the monkey in vitro. Implications for combined spinal-epidural anesthesia. Anesthesiology 1994;80:853-8.  Back to cited text no. 8
Cascio M, Heath G. Meningitis following a combined spinal-epidural technique in a labouring term parturient. Can J Anaesth 1996;43:399-402.  Back to cited text no. 9
Morgan BM, Kadim MY. Mobile regional analgesia in labour. Br J Obstet Gynaecol 1994;101:839-41.  Back to cited text no. 10
Casati A, D'Ambrosio A, De Negri P, Fanelli G, Tagariello V, Tarantino F. A clinical comparison between needle-through-needle and double-segment techniques for combined spinal and epidural anesthesia. Reg Anesth Pain Med 1998;23:390-4.  Back to cited text no. 11
Puolakka R, Pitkänen MT, Rosenberg PH. Comparison of technical and block characteristics of different combined spinal and epidural anesthesia techniques. Reg Anesth Pain Med 2001;26:17-23.  Back to cited text no. 12
Lyons G, Macdonald R, Mikl B. Combined epidural/spinal anaesthesia for caesarean section. Through the needle or in separate spaces? Anaesthesia 1992;47:199-201.  Back to cited text no. 13
Cook TM. 201 combined spinal-epidurals for anaesthesia using a separate needle technique. Eur J Anaesthesiol 2004;21:679-83.  Back to cited text no. 14
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  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]

  [Table 1], [Table 2]


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