Immediate Versus Overnight-Delayed Digital Replantation: Comparative Retrospective Cohort Study of Survival Outcomes

      Purpose

      Ischemia time has been traditionally considered a critical factor in replantation survival rate. The objective of this study was to compare the survival rate between immediate and overnight-delayed digital replantation.

      Methods

      We performed a retrospective cohort study of all digital replantations performed at our clinic between 2005 and 2016. The survival rate was compared between the immediate digital replantation group (immediate replantation group) and those that were replanted the morning after they were admitted to the hospital (overnight-delayed replantation group). The decision to delay the replant was made in cases admitted in the evening with less than 12 hours of previous ischemia time and without farm-related contamination.

      Results

      Five hundred ninety-seven digital replantations (456 patients) were analyzed. One hundred eighty-five (31%) digital replantations were performed the following day (delayed replantation group) and 412 (69%) digital replantations were performed the same day that they were admitted to the hospital (immediate replantation group). The overall survival rate was 91.9% (549 of 597). In the immediate replantation group, the survival rate was 91.2% (376 of 412) and in the delayed replantation group, the survival rate was 93.4% (174 of 185). There were no statistically significant differences between the immediate and the delayed replantation groups with respect to age, zone of amputation, or presence of multiple amputations.

      Conclusions

      Our study suggests that overnight delay is a safe approach for digital replantation when performed by experienced microsurgeons.

      Type of study/level of evidence

      Prognostic IV.

      Key words

      Since the first reported surgical reattachment of an amputated thumb in 1967,
      • Masuhara K.
      • Tamai S.
      • Fukunishi H.
      • Obama K.
      • Komatsu S.
      Experience with reanastomosis of the amputated thumb.
      replantation has become routine in many centers around the world. Survival rates in digital replantation range between 53% and 96% according to a recent meta-analysis.
      • Ma Z.
      • Guo F.
      • Qi J.
      • Xiang W.
      • Zhang J.
      Effects of non-surgical factors on digital replantation survival rate: a meta-analysis.
      Although other factors play a role, it is accepted that proper surgical technique is a critical factor for a successful digital replantation.
      • Morrison W.A.
      • McCombe D.
      Digital replantation.
      Consistently high success rates in digital replantation can be achieved only in high-volume microsurgery centers.
      The Journal of Hand Surgery will contain at least 2 clinically relevant articles selected by the editor to be offered for CME in each issue. For CME credit, the participant must read the articles in print or online and correctly answer all related questions through an online examination. The questions on the test are designed to make the reader think and will occasionally require the reader to go back and scrutinize the article for details.
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      Disclosures for this Article

      Editors

      Jennifer Moriatis Wolf, MD, has no relevant conflicts of interest to disclose.

      Authors

      All authors of this journal-based CME activity have no relevant conflicts of interest to disclose. In the printed or PDF version of this article, author affiliations can be found at the bottom of the first page.

      Planners

      Jennifer Moriatis Wolf, MD, has no relevant conflicts of interest to disclose. The editorial and education staff involved with this journal-based CME activity has no relevant conflicts of interest to disclose.

      Learning Objectives

      Upon completion of this CME activity, the learner should achieve an understanding of:
      • The basis of the original teaching that microsurgical replantation was a surgical emergency
      • The evidence comparing immediate to delayed replantation with regard to viability
      • The impact of age, zone of amputation, or multiple digits on the viability of immediate and delayed replantation
      Deadline: Each examination purchased in 2018 must be completed by January 31, 2019, to be eligible for CME. A certificate will be issued upon completion of the activity. Estimated time to complete each JHS CME activity is up to one hour.
      Copyright © 2018 by the American Society for Surgery of the Hand. All rights reserved.
      Ischemia time has been traditionally considered a critical factor in the survival rate but 2 recent meta-analyses found ischemia time does not have a significant influence on the survival of digits replanted after amputation.
      • Ma Z.
      • Guo F.
      • Qi J.
      • Xiang W.
      • Zhang J.
      Effects of non-surgical factors on digital replantation survival rate: a meta-analysis.
      • Yu H.
      • Wei L.
      • Liang B.
      • Hou S.
      • Wang J.
      • Yang Y.
      Nonsurgical factors of digital replantation and survival rate: a metaanalysis.
      Another recent study found that only warm ischemia time less than 6 hours and 30 minutes and replantations done during daylight hours influenced digit survival.
      • Breahna A.
      • Siddiqui A.
      • Fitzgerald O'Connor E.
      • Iwuagwu F.C.
      Replantation of digits: a review of predictive factors for survival.
      That study suggested that replantations done in daylight hours, when feasible, with rested personnel and a fully staffed operating room, were more likely to be successful, although the overall success rate of the series was only 70%. Based on this same observation, the senior author (P.C.C.) has been using an overnight-delayed approach for digital replantation for the last 11 years. This approach consists of delaying the replantation of amputated fingers in patients admitted to the hospital after 6 pm, provided the previous cold ischemia time is less than 12 hours (6 hours if warm), until the next morning at 8 am. We hypothesized that the survival rate is not affected by the extra time of cold ischemia incurred. The objective of this study was to compare the survival rate between immediate digital replantation and delayed digital replantation.

      Methods

      A retrospective analysis of institutional medical records was undertaken to identify all digital replantations performed at the unit between January 2005 and December 2016. The inclusion criterion was a complete amputation of 1 or more digits distal to the palmar-digital crease. All amputated fingers whose replantation was delayed overnight were kept in the refrigerator at 4°C to 6°C.
      A post hoc power calculation was done to determine if the sample assembled was sufficiently large to address the research question. Rate of survival in the 2 groups was considered the primary outcome variable used to establish the power. The number of predictor variables was determined by the number of occurrences of interest, replant failures, which was a total of 48. According to this, up to 6 predictor variables could be modeled. According to the sample size calculation, the minimum sample size to achieve a minimally acceptable level of statistical power was 400.
      • Peduzzi P.
      • Concato J.
      • Kemper E.
      • Holford T.R.
      • Feinstein A.R.
      A simulation study of the number of events per variable in logistic regression analysis.
      For each finger, the following variables were identified: zone of amputation, the age of the patient, and single- or multiple-digital amputation, which was considered a surrogate for injury severity. Typically, more severe injuries might be associated with a greater number of digits amputated. At least 1 arterial and 1 venous anastomosis were done in each digit. All these variables were considered independent. The dependent variable was survival (failure or success).

      Statistical methods

      A multivariable analysis was performed using logistic regression comparing the survival rate between the immediate digital replantation group and the overnight-delayed replantation group. A forced entry method was used with a judicious choosing of the variables based on a thorough review of the literature. The survival rates were adjusted by 3 independent variables and these were presented as odds ratios with 95% confidence intervals. Only 3 independent variables were included in the model to avoid overfitting. A P value less than .05 was considered statistically significant.

      The overnight-delay replantation protocol

      Patients with amputated digits admitted to the hospital later than 6 pm are replanted the following morning at 8 am. In general, only ischemia-sensitive replants are performed immediately if admitted at night. These include transmetacarpal or more proximal upper limb amputations, lower limbs, digits with extended previous ischemia times (> 6 hours warm or 12 hours cold ischemia), digital amputations associated with more proximal crushing and heavily contaminated injuries, or farm-related digital amputations. The amputated digits are kept at 4°C to 6°C in a refrigerator. The goal is to not exceed 24 hours of total cold ischemia before restoration of arterial circulation, assuming about 2 hours of operative time per digit, which is the standard time for our team. In cases of in-continuity zone I amputations connected only by the flexor digitorum profundus tendon or a stretched and damaged digital nerve (traction injuries), the amputation was completed at the bedside (with local anesthesia instillation if necessary) and the part kept refrigerated overnight. Given the minimal active distal interphalangeal joint flexion and extension after replantation in zone I, the morbidity added by this maneuver was considered to be negligible. In zone II amputations with flexor tendon in continuity, the replant was performed immediately because there is no practical way of cooling the digit without sectioning the flexor tendon.
      In order to keep the operative times low (∼ 2 hours per digit), an artery-last sequence of repairs is followed, sequentially repairing the structures in the following order under tourniquet control: bone (K-wires), extensor tendon, dorsal veins, dorsal skin, artery, nerves, and volar skin. This sequence of repairs allows working in a bloodless field and, in the senior authoŕs (P.C.C.) experience, is safe and faster than the more classic sequence of repairing the artery first. Replantation of 1 digit is a relatively rapid and straightforward procedure that does not interfere much with the normal surgical schedule of the day. If a 2- or more-digit replantation is to be delayed overnight, the surgery is started at 7 am to minimize the impact on the surgical schedule. Four- or more-digit replants usually require the cancellation of some scheduled cases or require immediate overnight replantation, depending on the previous ischemia time.

      Results

      Five hundred ninety-seven digital replantations in 456 patients were analyzed. The majority (93%) of the cases were operated on by the senior author (P.C.C.). Descriptive statistic values are presented in Table 1. The mean age was 42 years. There were 494 men (82.7%) and 103 women (17.3%). The level of amputation was zone I in 396 digits (66.3%) and zone II in 201 digits (33.7%). Two hundred thirteen digits (35.8%) were replanted in the context of multiple digit replantation and 383 digits (64.2%) were replanted as single digit. Vein grafts were used in 127 digits (21.3%). Two arterial anastomoses were done in 76 digits (12.7%). In 300 digits (50.3%), 2 vein anastomoses were performed. The digit most commonly replanted was the index finger (25.9%), followed by the thumb (23.4%), the ring (22.3%), the middle (20.8%), and the little finger (7.6%).
      Table 1The Mean (SD) and the Median (First, Third Quartiles) Were Calculated for Quantitative Variables; Absolute and Relative Frequencies Were Calculated for Categorical Variables
      VariableOne-Night Delayed Approach (n = 185) (31%)

      Mean (SD)

      Median (First Third Quartiles)
      Immediate Approach (n = 412) (69%)

      Mean (SD)

      Median (First, Third Quartiles)
      Total (n = 597)

      Mean (SD)

      Median (First, Third Quartiles)
      Age (y)38.72 (15.6)42.78 (13.79)41.52 (14.47)
      39 (29, 50.5)45 (32, 54)41.5 (31, 53)
      Survival
       No (failure)12 (6.6%)36 (8.8%)48 (8.1%)
       Yes (success)174 (93.4%)375 (91.2%)549 (91.9%)
      Zone
       I(60.8%)(68.8%)396 (66.3%)
       II(39.2%)(31.2%)201 (33.7%)
      Finger
       1(32.8%)(19.1%)(23.4%)
       2(19.7%)(28.7%)(25.9%)
       3(23%)(19.9%)(20.8%)
       4(18%)(24.3%)(22.3%)
       5(6.6%)(8.1%)(7.6%)
      Unidigital/multidigital
       Multidigital(24.6%)(40.8%)213 (35.8%)
       Unidigital(75.4%)(59.2%)383 (64.2%)
      Artery
       1(82%)(89.7%)521 (87.3%)
       2(18%)(10.3%)76 (12.7%)
      Vein
       1(39.3%)(47.1%)267 (44.7%)
       2(55.7%)(47.8%)300 (50.3%)
       3(4.9%)(5.1%)30 (5.1%)
      Vein graft
       No(88.5%)(74.3%)470 (78.7%)
       Yes(11.5%)(25.7%)127 (21.3%)
      Gender
       Male(83.6%)(82.4%)494 (82.7%)
       Female(16.4%)(17.6%)103 (17.3%)
      One hundred eighty-five (31%) digital replantations were performed the morning after admission (overnight-delayed replantation group) and 412 (69%) digital replantations were performed the same day of admission (immediate replantation group). The survival rate of digital replantation in the overnight-delayed replantation group was 93.4% (114 of 122) and in the immediate replantation group was 91.2% (222 of 248). This difference was not statistically significant (odds ratio, 1.15; 95% confidence interval, 0.50–2.99; P = .73).
      Neither the age, level of amputation, nor multiple-digit amputation negatively affected the survival rate between the 2 groups (Table 2). There were no statistically significant differences (P > .05) for any of these variables comparing the 2 groups. Figure 1 shows the probability of survival for the different categories of every independent variable analyzed in the study.
      Table 2Logistic Regression Was Performed to Test the Effect of Many Variables on Probability of Failure
      VariableOR95% CIP Value
      Immediate vs delayed approach1.1700.499–2.980.73
      Unidigital/multidigital (Uni)0.4650.203–1.044.06
      Vein graft (yes)1.9570.759–4.837.15
      Zone II1.1330.494–2.662.77
      Age (y)0.9850.957–1.012.26
      Gender female0.9030.306–2.306.84
      Finger 20.8730.269–2.927.82
      Finger 30.7810.222–2.736.69
      Finger 41.1240.345–3.832.85
      Finger 51.6450.370–6.650.49
      95% CI, 95% confidence interval; OR, odds ratio.
      Figure thumbnail gr1
      Figure 1Probability of survival and 95% confidence intervals are represented for the different categories of all the independent variables included in the study.

      Discussion

      Digital replantation is a sophisticated surgical procedure that involves judgment and refined skills. In order to maintain consistently high success rates, the teams need continuous high-volume exposure, with 24/7 availability. The logistic burden it adds to an already busy microsurgical practice is significant, with patients frequently arriving at the hospital at late hours. The overnight availability of the most experienced senior surgeons may be problematic. In small teams, like the authors’, this is an extra burden for surgeons who already have a busy surgical schedule. The fact that the most experienced senior surgeons are not usually involved in finger replantations may, at least in part, explain the low success rates reported in some series.
      The classic teaching, that longer ischemia times are detrimental to the success of digital replantation, is not supported by recent literature, which shows no difference in survival rates below or above 12 h of ischemia.
      • Ma Z.
      • Guo F.
      • Qi J.
      • Xiang W.
      • Zhang J.
      Effects of non-surgical factors on digital replantation survival rate: a meta-analysis.
      • Yu H.
      • Wei L.
      • Liang B.
      • Hou S.
      • Wang J.
      • Yang Y.
      Nonsurgical factors of digital replantation and survival rate: a metaanalysis.
      • Heistein J.B.
      • Cook P.A.
      Factors affecting composite graft survival in digital tip amputations.
      • Ren Z.P.
      • Liu Y.H.
      • Liu D.
      • Liang Y.H.
      The related factors affecting the survival rate of fingertip replantation.
      • Lin C.H.
      • Aydyn N.
      • Lin Y.T.
      • Hsu C.T.
      • Lin C.H.
      • Yeh J.T.
      Hand and finger replantation after protracted ischemia (more than 24 hours).
      The experience of the senior author (P.C.C.) had been the same, and the policy of overnight-delayed replantation was adopted in 2003. Only 1 recent study including 291 digital replants shows that ischemia time over 12 hours is a risk factor for replant failure.
      • Zhu X.
      • Zhu H.
      • Zhang C.
      • Zheng X.
      Pre-operative predictive factors for the survival of replanted digits.
      Nonetheless, the main point of the present paper is not to demonstrate that extended ischemia is well tolerated in finger replantation (which has already been demonstrated in the literature), but to suggest that delaying the replantation overnight can be a safe and efficient maneuver to handle these cases. The findings of the present study are in keeping with the study reported by Woo et al
      • Woo S.H.
      • Cheon H.J.
      • Kim Y.W.
      • Kang D.H.
      • Nam H.J.
      Delayed and suspended replantation for complete amputation of digits and hands.
      including 28 digits and 4 hands. They reported similar survival rates in delayed finger replantations compared with immediate replantation cases and discouraged delayed replantation only in cases of multiple-digit and hand amputations.
      In our study, there were no statistically significant differences between the immediate replantation group and the overnight-delayed replantation group, independent of the, age, zone of amputation, use of vein grafts, or single or multiple amputation. In the multiple-digit amputation group, the risk for failure was higher than in the single-digit replantation group, but the difference did not reach statistical significance (P = .07).
      The interference of emergency cases with scheduled surgeries in small teams is also an issue. The overnight-delayed replantation protocol may contribute to minimizing this interference, provided enough experience allows rapid replantation technique. The present study was performed in a busy microsurgical, private practice team, with highly committed members, extensive experience in replantation surgery, and a very low threshold for replantation of amputation injuries. These results should probably not be extrapolated to teams working in different conditions.
      The overnight-delayed replantation approach offers several advantages. It relieves the working pressure of overnight surgeries on the members of the team and reduces the overall cost per case. It allows the surgeries to be performed under optimal conditions, with a rested surgical team and a fully staffed operating room. This may, in part, explain the good results obtained in the delayed replantation group, in keeping with others reporting better survival of replants performed during daylight time.
      • Breahna A.
      • Siddiqui A.
      • Fitzgerald O'Connor E.
      • Iwuagwu F.C.
      Replantation of digits: a review of predictive factors for survival.
      The present study has limitations. It is a retrospective study, and the data on ischemia time may not have been accurate. The large size of the sample and the fact that the vast majority of the surgeries were performed by a single surgeon are advantages.
      In conclusion, the present study suggests that, in selected cases, the results of delaying replantation of digits overnight gives results comparable with those of immediate replantation. This approach should be considered only in highly committed and experienced microsurgical teams working in optimal environments.

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